Catalyzes the reversible stereospecific interconversion of fumarate to L-malate (PubMed:30761759). Experiments in other species have demonstrated that specific isoforms of this protein act in defined pathways and favor one direction over the other (Probable) Catalyzes the hydration of fumarate to L-malate in the tricarboxylic acid (TCA) cycle to facilitate a transition step in the production of energy in the form of NADH Catalyzes the dehydration of L-malate to fumarate (By similarity). Fumarate

MitochondrionCytoplasm, cytosolNucleusChromosome

Fumarase deficiency

A severe autosomal recessive metabolic disorder characterized by early-onset hypotonia, profound psychomotor retardation, and brain abnormalities, such as agenesis of the corpus callosum, gyral defects, and ventriculomegaly. Many patients show neonatal distress, metabolic acidosis, and/or encephalopathy.

Subunit 8, of the mitochondrial membrane ATP synthase complex (F(1)F(0) ATP synthase or Complex V) that produces ATP from ADP in the presence of a proton gradient across the membrane which is generated by electron transport complexes of the respiratory chain (PubMed:37244256). ATP synthase complex consist of a soluble F(1) head domain - the catalytic core - and a membrane F(1) domain - the membrane proton channel (PubMed:37244256). These two domains are linked by a central stalk rotating inside

Mitochondrion membrane

Mitochondrial complex V deficiency, mitochondrial 2

A mitochondrial disorder with heterogeneous clinical manifestations including neuropathy, ataxia, hypertrophic cardiomyopathy. Hypertrophic cardiomyopathy can present with negligible to extreme hypertrophy, minimal to extensive fibrosis and myocyte disarray, absent to severe left ventricular outflow tract obstruction, and distinct septal contours/morphologies with extremely varying clinical course.

Accepts electrons from ETF and reduces ubiquinone

Mitochondrion inner membrane

Glutaric aciduria 2C

An autosomal recessively inherited disorder of fatty acid, amino acid, and choline metabolism. It is characterized by multiple acyl-CoA dehydrogenase deficiencies resulting in large excretion not only of glutaric acid, but also of lactic, ethylmalonic, butyric, isobutyric, 2-methyl-butyric, and isovaleric acids.

Heterodimeric electron transfer flavoprotein that accepts electrons from several mitochondrial dehydrogenases, including acyl-CoA dehydrogenases, glutaryl-CoA and sarcosine dehydrogenase (PubMed:10356313, PubMed:15159392, PubMed:15975918, PubMed:27499296, PubMed:9334218). It transfers the electrons to the main mitochondrial respiratory chain via ETF-ubiquinone oxidoreductase (ETF dehydrogenase) (PubMed:9334218). Required for normal mitochondrial fatty acid oxidation and normal amino acid metabol

Mitochondrion matrix

Glutaric aciduria 2A

An autosomal recessively inherited disorder of fatty acid, amino acid, and choline metabolism. It is characterized by multiple acyl-CoA dehydrogenase deficiencies resulting in large excretion not only of glutaric acid, but also of lactic, ethylmalonic, butyric, isobutyric, 2-methyl-butyric, and isovaleric acids.

May play a role in RNA metabolism in both nuclei and mitochondria. In the nucleus binds to HNRPA1-associated poly(A) mRNAs and is part of nmRNP complexes at late stages of mRNA maturation which are possibly associated with nuclear mRNA export. Positively modulates nuclear export of mRNAs containing the EIF4E sensitivity element (4ESE) by binding simultaneously to both EIF4E and the 4ESE and acting as a platform for assembly for the RNA export complex (PubMed:19262567, PubMed:28325843). Also bind

MitochondrionNucleusNucleus, nucleoplasmNucleus inner membraneNucleus outer membrane

Mitochondrial complex IV deficiency, nuclear type 5

An autosomal recessive, severe mitochondrial disease with multisystemic manifestations and early onset. Clinical features include delayed psychomotor development, impaired intellectual development with speech delay, mild dysmorphic facial features, hypotonia, ataxia, and seizures. Brain imaging shows bilaterally symmetrical necrotic lesions in subcortical brain regions. Mortality is high, due to episodes of severe metabolic acidosis and coma.

Accessory subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I), that is believed not to be involved in catalysis. Complex I functions in the transfer of electrons from NADH to the respiratory chain. The immediate electron acceptor for the enzyme is believed to be ubiquinone

Mitochondrion inner membrane

Mitochondrial complex I deficiency, nuclear type 25

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN25 transmission pattern is consistent with autosomal recessive inheritance.

Core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) which catalyzes electron transfer from NADH through the respiratory chain, using ubiquinone as an electron acceptor (Probable). Parts of the peripheral arm of the enzyme, where the electrons from NADH are accepted by flavin mononucleotide (FMN) and then passed along a chain of iron-sulfur clusters by electron tunnelling to the final acceptor ubiquinone (Probable). Contains one iron-sulfur cluster (Probabl

Mitochondrion inner membrane

Mitochondrial complex I deficiency, nuclear type 7

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN7 transmission pattern is consistent with autosomal recessive inheritance.

Catalyzes the NADPH-dependent reduction of trans-2-enoyl thioesters in mitochondrial fatty acid synthesis (fatty acid synthesis type II). Fatty acid chain elongation in mitochondria uses acyl carrier protein (ACP) as an acyl group carrier, but the enzyme accepts both ACP and CoA thioesters as substrates in vitro. Displays a preference for medium-chain over short- and long-chain substrates (PubMed:12654921, PubMed:18479707, PubMed:27817865). May provide the octanoyl chain used for lipoic acid bio

MitochondrionCytoplasmNucleus

Dystonia, childhood-onset, with optic atrophy and basal ganglia abnormalities

An autosomal recessive neurologic disorder characterized by childhood-onset dystonia, basal ganglia degeneration and optic atrophy with decreased visual acuity. Dystonia is defined by the presence of sustained involuntary muscle contraction, often leading to abnormal postures. DYTOABG severity is variable, and some patients lose independent ambulation.

Bifunctional enzyme acting on the peroxisomal fatty acid beta-oxidation pathway. Catalyzes two of the four reactions in fatty acid degradation: hydration of 2-enoyl-CoA (trans-2-enoyl-CoA) to produce (3R)-3-hydroxyacyl-CoA, and dehydrogenation of (3R)-3-hydroxyacyl-CoA to produce 3-ketoacyl-CoA (3-oxoacyl-CoA), which is further metabolized by SCPx. Can use straight-chain and branched-chain fatty acids, as well as bile acid intermediates as substrates

Peroxisome

D-bifunctional protein deficiency

Disorder of peroxisomal fatty acid beta-oxidation.

Functions both as NADH oxidoreductase and as regulator of apoptosis (PubMed:17094969, PubMed:20362274, PubMed:23217327, PubMed:33168626). In response to apoptotic stimuli, it is released from the mitochondrion intermembrane space into the cytosol and to the nucleus, where it functions as a proapoptotic factor in a caspase-independent pathway (PubMed:20362274). Release into the cytoplasm is mediated upon binding to poly-ADP-ribose chains (By similarity). The soluble form (AIFsol) found in the nuc

Mitochondrion intermembrane spaceMitochondrion inner membraneCytoplasmNucleusCytoplasm, perinuclear regionMitochondrionCytoplasm, cytosol

Combined oxidative phosphorylation deficiency 6

A mitochondrial disease resulting in a neurodegenerative disorder characterized by psychomotor delay, hypotonia, areflexia, muscle weakness and wasting. Some patients manifest prenatal ventriculomegaly and severe postnatal encephalomyopathy.

Catalyzes the formation of fatty acid-cholesterol esters, which are less soluble in membranes than cholesterol (PubMed:16154994, PubMed:16647063, PubMed:32433613, PubMed:32433614, PubMed:32944968, PubMed:9020103). Plays a role in lipoprotein assembly and dietary cholesterol absorption (PubMed:16154994, PubMed:9020103). Preferentially utilizes oleoyl-CoA ((9Z)-octadecenoyl-CoA) as a substrate: shows a higher activity towards an acyl-CoA substrate with a double bond at the delta-9 position (9Z) th

Endoplasmic reticulum membrane

Core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) which catalyzes electron transfer from NADH through the respiratory chain, using ubiquinone as an electron acceptor (PubMed:16996290). Essential for the catalytic activity and assembly of complex I (PubMed:16996290)

Mitochondrion inner membrane

Leber hereditary optic neuropathy

A maternally inherited form of Leber hereditary optic neuropathy, a mitochondrial disease resulting in bilateral painless loss of central vision due to selective degeneration of the retinal ganglion cells and their axons. The disorder shows incomplete penetrance and male predominance. Cardiac conduction defects and neurological defects have also been described in some LHON patients. LHON results from primary mitochondrial DNA mutations affecting the respiratory chain complexes.

Lipoyl amidotransferase that catalyzes the transfer of lipoyl moieties from lipoyl-protein H of the glycine cleavage system (lipoyl-GCSH) to E2 subunits of the pyruvate dehydrogenase complex (PDCE2) (PubMed:29987032). Unable to catalyze the transfer of octanoyl from octanoyl-GCSH to PDCE2 (PubMed:29987032). In vitro, it is also able to catalyze the transfer of the lipoyl group from lipoyl-AMP to the specific lysine residue of lipoyl domains of lipoate-dependent enzymes but this reaction may not

Mitochondrion

Lipoyltransferase 1 deficiency

An autosomal recessive disorder due to a defect in lipoic acid metabolism, resulting in severe lactic acidosis and metabolic decompensation. Variable clinical manifestations include delayed psychomotor development, severe hypotonia, dystonia, loss of head control, coma, bradycardia, and pulmonary hypertension.

E3 ubiquitin-protein ligase component of the LUBAC complex which conjugates linear ('Met-1'-linked) polyubiquitin chains to substrates and plays a key role in NF-kappa-B activation and regulation of inflammation (PubMed:17006537, PubMed:19136968, PubMed:20005846, PubMed:21455173, PubMed:21455180, PubMed:21455181, PubMed:22863777, PubMed:28189684, PubMed:28481331). LUBAC conjugates linear polyubiquitin to IKBKG and RIPK1 and is involved in activation of the canonical NF-kappa-B and the JNK signal

Cytoplasm

Immunodeficiency 115 with autoinflammation

An autosomal recessive immunologic disorder manifesting in early infancy and characterized by combined immunodeficiency, recurrent bacterial, viral, and fungal infections, as well as autoinflammatory features, including arthritis and dermatitis.

May have a role in maintaining the integrity of the blood vessels. Has growth promoting activity on endothelial cells, angiogenic activity in vivo and chemotactic activity on endothelial cells in vitro Catalyzes the reversible phosphorolysis of thymidine. The produced molecules are then utilized as carbon and energy sources or in the rescue of pyrimidine bases for nucleotide synthesis

Mitochondrial DNA depletion syndrome 1, MNGIE type

A multisystem disease associated with mitochondrial dysfunction. It is clinically characterized by onset between the second and fifth decades of life, ptosis, progressive external ophthalmoplegia, gastrointestinal dysmotility (often pseudoobstruction), diffuse leukoencephalopathy, cachexia, peripheral neuropathy, and myopathy.

Required for the assembly of the ubiquinol-cytochrome c reductase complex (mitochondrial respiratory chain complex III or cytochrome b-c1 complex). Plays a role in the modulation of respiratory chain activities such as oxygen consumption and ATP production and via its modulation of the respiratory chain activity can regulate skeletal muscle differentiation and insulin secretion by pancreatic beta-cells. Involved in cytochrome b translation and/or stability

Mitochondrion matrix, mitochondrion nucleoidMitochondrionMitochondrion intermembrane spaceMitochondrion matrixMitochondrion inner membrane

Mitochondrial complex III deficiency, nuclear type 7

A form of mitochondrial complex III deficiency, a disorder of the mitochondrial respiratory chain resulting in a highly variable phenotype depending on which tissues are affected. MC3DN7 is characterized by severe intrauterine growth retardation, neonatal lactic acidosis and renal tubular dysfunction. Additional clinical features include a dysmorphic facial appearance, delayed psychomotor development, autistic features, aggressive behavior, and mild sensorineural hearing loss.

Component of the ubiquinol-cytochrome c oxidoreductase, a multisubunit transmembrane complex that is part of the mitochondrial electron transport chain which drives oxidative phosphorylation. The respiratory chain contains 3 multisubunit complexes succinate dehydrogenase (complex II, CII), ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III, CIII) and cytochrome c oxidase (complex IV, CIV), that cooperate to transfer electrons derived from NADH and succinate to molecular

Mitochondrion inner membrane

Mitochondrial complex III deficiency, nuclear type 5

A disorder of the mitochondrial respiratory chain resulting in a highly variable phenotype depending on which tissues are affected. Clinical features include mitochondrial encephalopathy, psychomotor retardation, ataxia, severe failure to thrive, liver dysfunction, renal tubulopathy, muscle weakness and exercise intolerance.

AMP deaminase plays a critical role in energy metabolism

Adenosine monophosphate deaminase deficiency erythrocyte type

A metabolic disorder due to lack of activity of the erythrocyte isoform of AMP deaminase. It is a clinically asymptomatic condition characterized by a 50% increase in steady-state levels of ATP in affected cells. Individuals with complete deficiency of erythrocyte AMP deaminase are healthy and have no hematologic disorders.

Very long-chain specific acyl-CoA dehydrogenase is one of the acyl-CoA dehydrogenases that catalyze the first step of mitochondrial fatty acid beta-oxidation (FAO), breaking down fatty acids into acetyl-CoA and allowing the production of energy from fats (PubMed:17564966, PubMed:18227065, PubMed:7668252, PubMed:9461620, PubMed:9599005, PubMed:9839948). The first step of FAO consists in the proR-proR stereospecific alpha, beta-dehydrogenation of fatty acyl-CoA thioesters using the electron transf

Mitochondrion inner membrane

Acyl-CoA dehydrogenase very long-chain deficiency

An inborn error of mitochondrial fatty acid beta-oxidation which leads to impaired long-chain fatty acid beta-oxidation. It is clinically heterogeneous, with three major phenotypes: a severe childhood form characterized by early onset, high mortality and high incidence of cardiomyopathy; a milder childhood form with later onset, characterized by hypoketotic hypoglycemia, low mortality and rare cardiomyopathy; an adult form, with isolated skeletal muscle involvement, rhabdomyolysis and myoglobinuria, usually triggered by exercise or fasting.

Together with PDHA1 forms the heterotetrameric E1 subunit of the pyruvate dehydrogenase (PDH) complex (PubMed:17474719, PubMed:19081061). The PDH complex catalyzes the overall conversion of pyruvate to acetyl-CoA and CO(2), and thereby links cytoplasmic glycolysis and the mitochondrial tricarboxylic acid (TCA) cycle (Probable). It contains multiple copies of three enzymatic components: pyruvate dehydrogenase (E1), dihydrolipoamide acetyltransferase (E2) and dihydrolipoamide dehydrogenase (E3) (P

Mitochondrion matrix

Pyruvate dehydrogenase E1-beta deficiency

An enzymatic defect causing primary lactic acidosis in children. It is associated with a broad clinical spectrum ranging from fatal lactic acidosis in the newborn to chronic neurologic dysfunction with structural abnormalities in the central nervous system without systemic acidosis.

Magnesium-independent polyisoprenoid diphosphatase that catalyzes the sequential dephosphorylation of presqualene, farnesyl, geranyl and geranylgeranyl diphosphates (PubMed:16464866, PubMed:19220020, PubMed:20110354). Functions in the innate immune response through the dephosphorylation of presqualene diphosphate which acts as a potent inhibitor of the signaling pathways contributing to polymorphonuclear neutrophils activation (PubMed:16464866, PubMed:23568778). May regulate the biosynthesis of

Endoplasmic reticulum membraneNucleus envelopeNucleus inner membrane

The pyruvate dehydrogenase (PDH) complex, catalyzes the overall conversion of pyruvate to acetyl-CoA and CO(2), and thereby links cytoplasmic glycolysis and the mitochondrial tricarboxylic acid (TCA) cycle (Probable). It contains multiple copies of three enzymatic components: pyruvate dehydrogenase (E1), dihydrolipoamide acetyltransferase (E2) and dihydrolipoamide dehydrogenase (E3); (Probable). Within this complex, the catalytic function of this enzyme is to accept, and to transfer to coenzyme

Mitochondrion matrix

Bidirectional proton-coupled monocarboxylate transporter (PubMed:12946269, PubMed:32946811, PubMed:33333023). Catalyzes the rapid transport across the plasma membrane of many monocarboxylates such as lactate, pyruvate, acetate and the ketone bodies acetoacetate and beta-hydroxybutyrate, and thus contributes to the maintenance of intracellular pH (PubMed:12946269, PubMed:33333023). The transport direction is determined by the proton motive force and the concentration gradient of the substrate mon

Cell membraneBasolateral cell membraneApical cell membrane

Symptomatic deficiency in lactate transport

Deficiency of lactate transporter may result in an acidic intracellular environment created by muscle activity with consequent degeneration of muscle and release of myoglobin and creatine kinase. This defect might compromise extreme performance in otherwise healthy individuals.

Hydrolyzes glucose-6-phosphate to glucose in the endoplasmic reticulum. Forms with the glucose-6-phosphate transporter (SLC37A4/G6PT) the complex responsible for glucose production in the terminal step of glycogenolysis and gluconeogenesis. Hence, it is the key enzyme in homeostatic regulation of blood glucose levels

Endoplasmic reticulum membrane

Glycogen storage disease 1A

A metabolic disorder characterized by impairment of terminal steps of glycogenolysis and gluconeogenesis. Patients manifest a wide range of clinical symptoms and biochemical abnormalities, including hypoglycemia, severe hepatomegaly due to excessive accumulation of glycogen, kidney enlargement, growth retardation, lactic acidemia, hyperlipidemia, and hyperuricemia.

Phosphorylates deoxyguanosine and deoxyadenosine in the mitochondrial matrix, with the highest efficiency for deoxyguanosine (PubMed:11687801, PubMed:17073823, PubMed:23043144, PubMed:8692979, PubMed:8706825). In non-replicating cells, where cytosolic dNTP synthesis is down-regulated, mtDNA synthesis depends solely on DGUOK and TK2. Phosphorylates certain nucleoside analogs (By similarity). Widely used as target of antiviral and chemotherapeutic agents

Mitochondrion

Mitochondrial DNA depletion syndrome 3

A disorder due to mitochondrial dysfunction characterized by onset in infancy of progressive liver failure, hypoglycemia, increased lactate in body fluids, and neurologic abnormalities including hypotonia, encephalopathy, peripheral neuropathy. Affected tissues show both decreased activity of the mtDNA-encoded respiratory chain complexes and mtDNA depletion.

E3 ubiquitin-protein ligase, which accepts ubiquitin from specific E2 ubiquitin-conjugating enzymes, such as UBE2L3/UBCM4, and then transfers it to substrates (PubMed:12629548, PubMed:17449468, PubMed:18711448). Functions as an E3 ligase for oxidized IREB2 and both heme and oxygen are necessary for IREB2 ubiquitination (PubMed:12629548). Promotes ubiquitination of TAB2 and IRF3 and their degradation by the proteasome (PubMed:17449468, PubMed:18711448). Component of the LUBAC complex which conjug

Polyglucosan body myopathy 1 with or without immunodeficiency

A disease characterized by polyglucosan storage myopathy associated with early-onset progressive muscle weakness and progressive dilated cardiomyopathy, which may necessitate cardiac transplant in severe cases. Some patients present with severe immunodeficiency, invasive bacterial infections and chronic autoinflammation.

Subunit a, of the mitochondrial membrane ATP synthase complex (F(1)F(0) ATP synthase or Complex V) that produces ATP from ADP in the presence of a proton gradient across the membrane which is generated by electron transport complexes of the respiratory chain (Probable). ATP synthase complex consist of a soluble F(1) head domain - the catalytic core - and a membrane F(1) domain - the membrane proton channel (PubMed:37244256). These two domains are linked by a central stalk rotating inside the F(1

Mitochondrion inner membrane

Neuropathy, ataxia, and retinitis pigmentosa

A syndrome characterized by variable combination of developmental delay, psychomotor retardation, hearing loss, optic atrophy and retinitis pigmentosa, dementia, seizures, ataxia, proximal neurogenic muscle weakness, and sensory neuropathy.

Core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) which catalyzes electron transfer from NADH through the respiratory chain, using ubiquinone as an electron acceptor (PubMed:15250827, PubMed:8344246, PubMed:8644732). Essential for the catalytic activity and assembly of complex I (PubMed:15250827, PubMed:8344246, PubMed:8644732)

Mitochondrion inner membrane

Leber hereditary optic neuropathy

A maternally inherited form of Leber hereditary optic neuropathy, a mitochondrial disease resulting in bilateral painless loss of central vision due to selective degeneration of the retinal ganglion cells and their axons. The disorder shows incomplete penetrance and male predominance. Cardiac conduction defects and neurological defects have also been described in some LHON patients. LHON results from primary mitochondrial DNA mutations affecting the respiratory chain complexes.

Regulator subunit of pancreatic ATP-sensitive potassium channel (KATP), playing a major role in the regulation of insulin release. In pancreatic cells, it forms KATP channels with KCNJ11; KCNJ11 forms the channel pore while ABCC8 is required for activation and regulation

Cell membrane

Leucine-induced hypoglycemia

Rare cause of hypoglycemia and is described as a condition in which symptomatic hypoglycemia is provoked by high protein feedings. Hypoglycemia is also elicited by administration of oral or intravenous infusions of a single amino acid, leucine.

Allows the formation of correctly charged Gln-tRNA(Gln) through the transamidation of misacylated Glu-tRNA(Gln) in the mitochondria. The reaction takes place in the presence of glutamine and ATP through an activated gamma-phospho-Glu-tRNA(Gln)

Mitochondrion

Combined oxidative phosphorylation deficiency 40

An autosomal recessive mitochondrial disorder characterized by prenatal or infantile onset, fetal hydrops, severe hypertrophic cardiomyopathy, poor growth, sensorineural hearing loss, hepatic dysfunction, lactic acidosis, and decreased activities of mitochondrial respiratory complexes I, III, IV, and V. The disorder is lethal, with death occurring in infancy.

Mitochondrion

Combined oxidative phosphorylation deficiency 9

A mitochondrial disease characterized by failure to thrive, poor feeding, hypertrophic cardiomyopathy, hepatomegaly, and psychomotor retardation. Death in infancy has been observed in some cases.

Catalyzes the attachment of alanine to tRNA(Ala) in a two-step reaction: alanine is first activated by ATP to form Ala-AMP and then transferred to the acceptor end of tRNA(Ala). Also edits incorrectly charged tRNA(Ala) via its editing domain (PubMed:21549344). In presence of high levels of lactate, also acts as a protein lactyltransferase that mediates lactylation of lysine residues in target proteins, such as CGAS (PubMed:39322678). Acts as an inhibitor of cGAS/STING signaling by catalyzing lac

Mitochondrion

Combined oxidative phosphorylation deficiency 8

A mitochondrial disease characterized by a lethal infantile hypertrophic cardiomyopathy, generalized muscle dysfunction and some neurologic involvement. The liver is not affected.

Core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) which catalyzes electron transfer from NADH through the respiratory chain, using ubiquinone as an electron acceptor (PubMed:1959619). Essential for the catalytic activity and assembly of complex I (PubMed:1959619, PubMed:26929434)

Mitochondrion inner membrane

Leber hereditary optic neuropathy

A maternally inherited form of Leber hereditary optic neuropathy, a mitochondrial disease resulting in bilateral painless loss of central vision due to selective degeneration of the retinal ganglion cells and their axons. The disorder shows incomplete penetrance and male predominance. Cardiac conduction defects and neurological defects have also been described in some LHON patients. LHON results from primary mitochondrial DNA mutations affecting the respiratory chain complexes.

Accessory subunit of DNA polymerase gamma solely responsible for replication of mitochondrial DNA (mtDNA). Acts as an allosteric regulator of the holoenzyme activities. Enhances the polymerase activity and the processivity of POLG by increasing its interactions with the DNA template. Suppresses POLG exonucleolytic proofreading especially toward homopolymeric templates bearing mismatched termini. Binds to single-stranded DNA

MitochondrionMitochondrion matrix, mitochondrion nucleoid

Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant, 4

A disorder characterized by progressive weakness of ocular muscles and levator muscle of the upper eyelid. In a minority of cases, it is associated with skeletal myopathy, which predominantly involves axial or proximal muscles and which causes abnormal fatigability and even permanent muscle weakness. Ragged-red fibers and atrophy are found on muscle biopsy. A large proportion of chronic ophthalmoplegias are associated with other symptoms, leading to a multisystemic pattern of this disease. Additional symptoms are variable, and may include cataracts, hearing loss, sensory axonal neuropathy, ataxia, depression, hypogonadism, and parkinsonism.

Essential for the assembly of the mitochondrial respiratory chain complex IV (CIV), also known as cytochrome c oxidase (PubMed:23125284). Acts as a chaperone in the early steps of cytochrome c oxidase subunit II (MT-CO2/COX2) maturation, stabilizing the newly synthesized protein and presenting it to metallochaperones SCO1/2 which in turn facilitates the incorporation of the mature MT-CO2/COX2 into the assembling CIV holoenzyme (PubMed:24403053)

Mitochondrion inner membrane

Mitochondrial complex IV deficiency, nuclear type 11

An autosomal recessive mitochondrial disorder with onset in childhood or adolescence. MC4DN11 is characterized by walking difficulties, cerebellar ataxia, dystonia, choreoathetotic movements and dysarthria. Additional features may include sensory axonal neuropathy, cerebellar atrophy, and mild speech delay. Cognitive function is normal. Serum lactate levels are increased. Patient tissues show decreased levels and activity of mitochondrial respiratory complex IV.

Core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) which catalyzes electron transfer from NADH through the respiratory chain, using ubiquinone as an electron acceptor (PubMed:14729820, PubMed:30140060). Essential for the catalytic activity and assembly of complex I (PubMed:14729820, PubMed:24028823, PubMed:30140060)

Mitochondrion inner membrane

Mitochondrial complex I deficiency, nuclear type 8

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN8 transmission pattern is consistent with autosomal recessive inheritance.

As part of the MCIA complex, involved in the assembly of the mitochondrial complex I (PubMed:27374773, PubMed:27374774, PubMed:32320651). Participates in constructing the membrane arm of complex I (PubMed:24191001)

Mitochondrion membrane

Mitochondrial complex I deficiency, nuclear type 29

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN29 transmission pattern is consistent with autosomal recessive inheritance.

Methionyl-tRNA formyltransferase that formylates methionyl-tRNA in mitochondria and is crucial for translation initiation

Mitochondrion

Combined oxidative phosphorylation deficiency 15

An autosomal recessive, mitochondrial, neurologic disorder characterized by features of Leigh syndrome and combined oxidative phosphorylation deficiency. Clinical features include mild global developmental delay, white matter abnormalities, ataxia, incoordination, speech and reading difficulties, T2-weighted hyperintensities in the basal ganglia, corpus callosum, and brainstem.

Accessory subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I), that is believed not to be involved in catalysis. Complex I functions in the transfer of electrons from NADH to the respiratory chain. The immediate electron acceptor for the enzyme is believed to be ubiquinone

Mitochondrion inner membrane

Mitochondrial complex I deficiency, nuclear type 12

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease.

Non-receptor tyrosine kinase involved in B-lymphocyte development, differentiation and signaling (By similarity). B-cell receptor (BCR) signaling requires a tight regulation of several protein tyrosine kinases and phosphatases, and associated coreceptors (By similarity). Binding of antigen to the B-cell antigen receptor (BCR) triggers signaling that ultimately leads to B-cell activation (By similarity). Signaling through BLK plays an important role in transmitting signals through surface immunog

Cell membrane

Maturity-onset diabetes of the young 11

A form of diabetes that is characterized by an autosomal dominant mode of inheritance, onset in childhood or early adulthood (usually before 25 years of age), a primary defect in insulin secretion and frequent insulin-independence at the beginning of the disease.

Insulin decreases blood glucose concentration. It increases cell permeability to monosaccharides, amino acids and fatty acids. It accelerates glycolysis, the pentose phosphate cycle, and glycogen synthesis in liver

Secreted

Hyperproinsulinemia

An autosomal dominant condition characterized by elevated levels of serum proinsulin-like material.

Catalyzes the 2-thiolation of uridine at the wobble position (U34) of mitochondrial tRNA(Lys), tRNA(Glu) and tRNA(Gln). Required for the formation of 5-taurinomethyl-2-thiouridine (tm5s2U) of mitochondrial tRNA(Lys), tRNA(Glu), and tRNA(Gln) at the wobble position. ATP is required to activate the C2 atom of the wobble base

Mitochondrion

Deafness, aminoglycoside-induced

A form of sensorineural deafness characterized by moderate-to-profound hearing loss and mitochondrial inheritance. It is induced by exposure to aminoglycosides.

Catalyzes the isomerization of citrate to isocitrate via cis-aconitate

Mitochondrion

Infantile cerebellar-retinal degeneration

A severe autosomal recessive neurodegenerative disorder characterized by onset between ages 2 and 6 months of truncal hypotonia, athetosis, seizures, and ophthalmologic abnormalities, particularly optic atrophy and retinal degeneration. Affected individuals show profound psychomotor retardation, with only some achieving rolling, sitting, or recognition of family. Brain MRI shows progressive cerebral and cerebellar degeneration.

Interconverts simultaneously and stereospecifically pyruvate and lactate with concomitant interconversion of NADH and NAD(+)

CytoplasmMitochondrion inner membrane

Lactate dehydrogenase B deficiency

A condition with no deleterious effects on health. LDHBD is of interest to laboratory medicine mainly because it can cause misdiagnosis in those disorders in which elevation of serum LDH is expected.

Pyruvate kinase that catalyzes the conversion of phosphoenolpyruvate to pyruvate with the synthesis of ATP, and which plays a key role in glycolysis

Pyruvate kinase hyperactivity

Autosomal dominant phenotype characterized by increase of red blood cell ATP.

Essential for the degradation of glycogen in lysosomes (PubMed:14695532, PubMed:18429042, PubMed:1856189, PubMed:7717400). Has highest activity on alpha-1,4-linked glycosidic linkages, but can also hydrolyze alpha-1,6-linked glucans (PubMed:29061980)

LysosomeLysosome membrane

Pompe disease, infantile-onset

An early-onset form of Pompe disease, an autosomal recessive lysosomal storage disease characterized by lysosomal alpha-glucosidase deficiency, a broad clinical spectrum and age at onset ranging from infancy to adulthood. The classic early-onset form of IOPD presents at birth with massive accumulation of glycogen in muscle, heart and liver. Cardiomyopathy and muscular hypotonia are the cardinal features of this form whose life expectancy is less than two years. A milder infantile form manifests as progressive muscular disorder of childhood and patients have better prognosis.

Catalyzes the attachment of leucine to its cognate tRNA

Mitochondrion matrix

Perrault syndrome 4

An autosomal recessive, sex-influenced disorder characterized by sensorineural deafness in both males and females, and ovarian dysgenesis in females. Affected females have primary amenorrhea, streak gonads, and infertility, whereas affected males show normal pubertal development and are fertile.

Possible ATPase (PubMed:15653697) involved in DNA replication, may facilitate loading of CDC45 onto pre-replication complexes (PubMed:20065034) An aminoacyl-tRNA editing enzyme that deacylates mischarged D-aminoacyl-tRNAs. Also deacylates mischarged glycyl-tRNA(Ala), protecting cells against glycine mischarging by AlaRS. Acts via tRNA-based rather than protein-based catalysis; rejects L-amino acids rather than detecting D-amino acids in the active site. By recycling D-aminoacyl-tRNA to D-amino a

NucleusCytoplasm

E3 ubiquitin-protein ligase. Together with the phosphatase EPM2A/laforin, appears to be involved in the clearance of toxic polyglucosan and protein aggregates via multiple pathways. In complex with EPM2A/laforin and HSP70, suppresses the cellular toxicity of misfolded proteins by promoting their degradation through the ubiquitin-proteasome system (UPS). Ubiquitinates the glycogen-targeting protein phosphatase subunits PPP1R3C/PTG and PPP1R3D in a laforin-dependent manner and targets them for pro

Endoplasmic reticulumNucleus

Myoclonic epilepsy of Lafora 2

A form of progressive myoclonic epilepsy, a clinically and genetically heterogeneous group of disorders defined by the combination of action and reflex myoclonus, other types of epileptic seizures, and progressive neurodegeneration and neurocognitive impairment. MELF2 is an autosomal recessive, severe form characterized by onset of progressive neurodegeneration between 8 and 18 years of age. Initial features can include headache, myoclonic jerks, generalized seizures, and often visual hallucination. Typically, as seizures increase in frequency, cognitive function declines towards dementia, and affected individuals die usually within 10 years after onset. At the cellular level, MELF2 is characterized by accumulation of starch-like polyglucosans called Lafora bodies (LBs) that are most abundant in organs with the highest glucose metabolism: brain, heart, liver and skeletal muscle.

Serves as the first electron transfer protein in all the mitochondrial P450 systems including cholesterol side chain cleavage in all steroidogenic tissues, steroid 11-beta hydroxylation in the adrenal cortex, 25-OH-vitamin D3-24 hydroxylation in the kidney, and sterol C-27 hydroxylation in the liver (By similarity). Also acts as a ferredoxin--NADP(+) reductase essential for coenzyme Q biosynthesis: together with FDX2, transfers the electrons required for the hydroxylation reaction performed by C

MitochondrionMitochondrion inner membrane

Auditory neuropathy and optic atrophy

An autosomal recessive disease characterized by hearing loss, visual impairment and optic atrophy, with onset in the first or second decades of life. Optic atrophy is caused by degeneration of nerve fibers which arise in the retina and converge to form the optic disk, optic nerve, optic chiasm and optic tracts.

Catalytic subunit of DNA polymerase gamma solely responsible for replication of mitochondrial DNA (mtDNA). Replicates both heavy and light strands of the circular mtDNA genome using a single-stranded DNA template, RNA primers and the four deoxyribonucleoside triphosphates as substrates (PubMed:11477093, PubMed:11897778, PubMed:15917273, PubMed:19837034, PubMed:9558343). Has 5' -> 3' polymerase activity. Functionally interacts with TWNK and SSBP1 at the replication fork to form a highly processiv

MitochondrionMitochondrion matrix, mitochondrion nucleoid

Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant, 1

A disorder characterized by progressive weakness of ocular muscles and levator muscle of the upper eyelid. In a minority of cases, it is associated with skeletal myopathy, which predominantly involves axial or proximal muscles and which causes abnormal fatigability and even permanent muscle weakness. Ragged-red fibers and atrophy are found on muscle biopsy. A large proportion of chronic ophthalmoplegias are associated with other symptoms, leading to a multisystemic pattern of this disease. Additional symptoms are variable, and may include cataracts, hearing loss, sensory axonal neuropathy, ataxia, depression, hypogonadism, and parkinsonism.

Subunit delta, of the mitochondrial membrane ATP synthase complex (F(1)F(0) ATP synthase or Complex V) that produces ATP from ADP in the presence of a proton gradient across the membrane which is generated by electron transport complexes of the respiratory chain (Probable) (PubMed:37244256). ATP synthase complex consist of a soluble F(1) head domain - the catalytic core - and a membrane F(1) domain - the membrane proton channel (PubMed:37244256). These two domains are linked by a central stalk r

MitochondrionMitochondrion inner membrane

Mitochondrial complex V deficiency, nuclear type 5

A mitochondrial disorder characterized by childhood onset of episodic metabolic decompensation featuring lactic acidosis and hyperammonemia accompanied by ketoacidosis or hypoglycemia. Chronic manifestations include developmental delay, easy fatiguability, and 3-methylglutaconic aciduria. The transmission pattern of MC5DN5 is consistent with autosomal recessive inheritance.

Copper metallochaperone essential for the synthesis and maturation of cytochrome c oxidase subunit II (MT-CO2/COX2); together with SCO1, facilitates the incorporation of copper into the Cu(A) site of MT-CO2/COX2 (PubMed:15229189, PubMed:17189203, PubMed:19336478, PubMed:35750769). Could also act as a thiol-disulfide oxidoreductase to regulate the redox state of the cysteines in SCO1 during maturation of MT-CO2/COX2 (PubMed:19336478)

Mitochondrion inner membrane

Mitochondrial complex IV deficiency, nuclear type 2

An autosomal recessive, severe mitochondrial disorder characterized by hypotonia, global developmental delay, hypertrophic cardiomyopathy, lactic acidosis, gliosis, and neuronal loss in basal ganglia, brainstem and spinal cord. Serum lactate is increased, and laboratory studies show decreased mitochondrial complex IV protein and activity levels in various tissues, including heart and skeletal muscle. Most patients die in infancy of cardiorespiratory failure.

Involved in the maturation of the mitochondrial respiratory chain complex IV subunit MT-CO2/COX2. Thereby, may regulate early steps of complex IV assembly. Mitochondrial respiratory chain complex IV or cytochrome c oxidase is the component of the respiratory chain that catalyzes the transfer of electrons from intermembrane space cytochrome c to molecular oxygen in the matrix and as a consequence contributes to the proton gradient involved in mitochondrial ATP synthesis. May also be required for

Mitochondrion intermembrane space

Mitochondrial complex IV deficiency, nuclear type 13

An autosomal recessive, infantile disorder with a fatal course in the first weeks of life, characterized by hypertrophic cardiomyopathy, left ventricular non-compaction, lactic acidosis, metabolic hypotonia, and mitochondrial complex IV deficiency.

Component of the ubiquinol-cytochrome c oxidoreductase, a multisubunit transmembrane complex that is part of the mitochondrial electron transport chain which drives oxidative phosphorylation. The respiratory chain contains 3 multisubunit complexes succinate dehydrogenase (complex II, CII), ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III, CIII) and cytochrome c oxidase (complex IV, CIV), that cooperate to transfer electrons derived from NADH and succinate to molecular

Mitochondrion inner membrane

Mitochondrial complex III deficiency, nuclear type 4

A disorder of the mitochondrial respiratory chain resulting in a highly variable phenotype depending on which tissues are affected. Clinical features include mitochondrial encephalopathy, psychomotor retardation, ataxia, severe failure to thrive, liver dysfunction, renal tubulopathy, muscle weakness and exercise intolerance.

Component of the ubiquinol-cytochrome c oxidoreductase, a multisubunit transmembrane complex that is part of the mitochondrial electron transport chain which drives oxidative phosphorylation (PubMed:31883641). The respiratory chain contains 3 multisubunit complexes succinate dehydrogenase (complex II, CII), ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III, CIII) and cytochrome c oxidase (complex IV, CIV), that cooperate to transfer electrons derived from NADH and succi

Mitochondrion inner membrane

Mitochondrial complex III deficiency, nuclear type 10

A form of mitochondrial complex III deficiency, a disorder of the mitochondrial respiratory chain resulting in a highly variable phenotype depending on which tissues are affected. MC3DN10 is an autosomal recessive form characterized by fetal bradycardia, poor feeding, hypotonia, hypertrophic cardiomyopathy, alopecia totalis, low mitochondrial complex III activity and lactic acidosis.

Core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) which catalyzes electron transfer from NADH through the respiratory chain, using ubiquinone as an electron acceptor (PubMed:17275378). Essential for the catalytic activity of complex I (PubMed:17275378)

Mitochondrion inner membrane

Mitochondrial complex I deficiency, nuclear type 3

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN3 transmission pattern is consistent with autosomal recessive inheritance.

Accessory subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I), that is believed not to be involved in catalysis. Complex I functions in the transfer of electrons from NADH to the respiratory chain. The immediate electron acceptor for the enzyme is believed to be ubiquinone

Mitochondrion matrix

Mitochondrial complex I deficiency, nuclear type 22

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN22 transmission pattern is consistent with autosomal recessive inheritance.

Iron-sulfur cluster transfer protein involved in the assembly of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) (PubMed:19752196). May deliver one or more Fe-S clusters to complex I subunits (PubMed:19752196)

Mitochondrion

Mitochondrial complex I deficiency, nuclear type 21

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN21 transmission pattern is consistent with autosomal recessive inheritance.

Core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) which catalyzes electron transfer from NADH through the respiratory chain, using ubiquinone as an electron acceptor (PubMed:22499348). Essential for the catalytic activity and assembly of complex I (PubMed:22499348)

Mitochondrion inner membrane

Mitochondrial complex I deficiency, nuclear type 2

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN2 inheritance is autosomal recessive.

Mitochondrial helicase involved in mtDNA replication and repair (PubMed:12975372, PubMed:15167897, PubMed:17324440, PubMed:18039713, PubMed:18971204, PubMed:25824949, PubMed:26887820, PubMed:27226550). Might have a role in mtDNA repair (PubMed:27226550). Has DNA strand separation activity needed to form a processive replication fork for leading strand synthesis which is catalyzed by the formation of a replisome complex with POLG and mtSDB (PubMed:12975372, PubMed:15167897, PubMed:18039713, PubMe

Mitochondrion matrix, mitochondrion nucleoidMitochondrion inner membrane

Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant, 3

A disorder characterized by progressive weakness of ocular muscles and levator muscle of the upper eyelid. In a minority of cases, it is associated with skeletal myopathy, which predominantly involves axial or proximal muscles and which causes abnormal fatigability and even permanent muscle weakness. Ragged-red fibers and atrophy are found on muscle biopsy. A large proportion of chronic ophthalmoplegias are associated with other symptoms, leading to a multisystemic pattern of this disease. Additional symptoms are variable, and may include cataracts, hearing loss, sensory axonal neuropathy, ataxia, depression, hypogonadism, and parkinsonism.

ATP-specific succinyl-CoA synthetase functions in the citric acid cycle (TCA), coupling the hydrolysis of succinyl-CoA to the synthesis of ATP and thus represents the only step of substrate-level phosphorylation in the TCA (PubMed:15877282, PubMed:34492704, PubMed:40108300). The beta subunit provides nucleotide specificity of the enzyme and binds the substrate succinate, while the binding sites for coenzyme A and phosphate are found in the alpha subunit (By similarity). Also able to act as an AT

Mitochondrion

Mitochondrial DNA depletion syndrome 5

A disorder due to mitochondrial dysfunction. It is characterized by infantile onset of hypotonia, neurologic deterioration, a hyperkinetic-dystonic movement disorder, external ophthalmoplegia, deafness, variable renal tubular dysfunction, and mild methylmalonic aciduria in some patients.

Catalyzes the hydrolysis of a wide range of substrates including cholesteryl esters, phospholipids, lysophospholipids, di- and tri-acylglycerols, and fatty acid esters of hydroxy fatty acids (FAHFAs) (PubMed:10220579, PubMed:27509211, PubMed:27650499, PubMed:8471055). Preferentially hydrolyzes FAHFAs with the ester bond further away from the carboxylate. Unsaturated FAHFAs are hydrolyzed more quickly than saturated FAHFAs (By similarity). Has an essential role in the complete digestion of dietar

Secreted

Maturity-onset diabetes of the young 8 with exocrine dysfunction

An autosomal dominant form of diabetes characterized by a primary defect in insulin secretion, exocrine pancreatic dysfunction, altered pancreatic morphology, recurrent abdominal pain, and fecal elastase deficiency. Disease onset is at less than 25 years of age.

Transcription factor (PubMed:10207080, PubMed:9748269). Activates the epsilon- and gamma-globin gene promoters and, to a much lower degree, the beta-globin gene and represses promoters containing SP1-like binding inhibiting cell growth (PubMed:10207080, PubMed:16131492, PubMed:9748269). Represses transcription of SMAD7 which enhances TGF-beta signaling (By similarity). Induces apoptosis (By similarity)

Nucleus

Maturity-onset diabetes of the young 7

A form of diabetes that is characterized by an autosomal dominant mode of inheritance, onset in childhood or early adulthood (usually before 25 years of age), a primary defect in insulin secretion and frequent insulin-independence at the beginning of the disease.

Plays an important role in the differentiation and development of pancreatic islet beta cells. Transcriptional repressor that binds to a common element in the glucagon, insulin and somatostatin promoters. Competes with PAX6 for this same promoter binding site. Isoform 2 appears to be a dominant negative form antagonizing PAX4 transcriptional activity

Nucleus

Type 2 diabetes mellitus

A multifactorial disorder of glucose homeostasis caused by a lack of sensitivity to insulin. Affected individuals usually have an obese body habitus and manifestations of a metabolic syndrome characterized by diabetes, insulin resistance, hypertension and hypertriglyceridemia. The disease results in long-term complications that affect the eyes, kidneys, nerves, and blood vessels.

Transcriptional regulator which controls the expression of hepatic genes during the transition of endodermal cells to hepatic progenitor cells, facilitating the recruitment of RNA pol II to the promoters of target genes (PubMed:30597922). Activates the transcription of CYP2C38 (By similarity). Represses the CLOCK-BMAL1 transcriptional activity and is essential for circadian rhythm maintenance and period regulation in the liver and colon cells (PubMed:30530698)

Nucleus

Maturity-onset diabetes of the young 1

A form of diabetes that is characterized by an autosomal dominant mode of inheritance, onset in childhood or early adulthood (usually before 25 years of age), a primary defect in insulin secretion and frequent insulin-independence at the beginning of the disease.

Catalyzes the attachment of arginine to tRNA(Arg) in a two-step reaction: arginine is first activated by ATP to form Arg-AMP and then transferred to the acceptor end of tRNA(Arg)

Mitochondrion membrane

Pontocerebellar hypoplasia 6

A disorder characterized by an abnormally small cerebellum and brainstem, infantile encephalopathy, generalized hypotonia, lethargy and poor feeding. Recurrent apnea, intractable seizures occur early in the course of this condition.

Probable GTPase that plays a role in the mitochondrial ribosomal small subunit assembly. Specifically binds the 12S mitochondrial rRNA (12S mt-rRNA) to a 33 nucleotide section delineating the 3' terminal stem-loop region. May act as a chaperone that protects the 12S mt-rRNA on the 28S mitoribosomal subunit during ribosomal small subunit assembly

Mitochondrion matrixMitochondrion inner membrane

Perrault syndrome 6

A form of Perrault syndrome, a sex-influenced disorder characterized by sensorineural deafness in both males and females, and ovarian dysgenesis in females. Affected females have primary amenorrhea, streak gonads, and infertility, whereas affected males show normal pubertal development and are fertile. PRLTS6 inheritance is autosomal recessive.

Catalytic component of the m-AAA protease, a protease that plays a key role in proteostasis of inner mitochondrial membrane proteins, and which is essential for axonal and neuron development (PubMed:19748354, PubMed:28396416, PubMed:29932645, PubMed:30683687, PubMed:31327635, PubMed:37917749, PubMed:38157846). AFG3L2 possesses both ATPase and protease activities: the ATPase activity is required to unfold substrates, threading them into the internal proteolytic cavity for hydrolysis into small pe

Mitochondrion inner membrane

Spinocerebellar ataxia 28

Spinocerebellar ataxia is a clinically and genetically heterogeneous group of cerebellar disorders. Patients show progressive incoordination of gait and often poor coordination of hands, speech and eye movements, due to degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCA28 is an autosomal dominant cerebellar ataxia (ADCA) with a slow progressive course and no evidence of sensory involvement or cognitive impairment.

Nucleus

Phosphorylase b kinase catalyzes the phosphorylation of serine in certain substrates, including troponin I. The alpha chain may bind calmodulin

Cell membrane

Glycogen storage disease 9D

A metabolic disorder characterized by slowly progressive, predominantly distal muscle weakness and atrophy. Clinical features include exercise intolerance with early fatigability, pain, cramps and occasionally myoglobinuria.

Component of the cytochrome c oxidase, the last enzyme in the mitochondrial electron transport chain which drives oxidative phosphorylation. The respiratory chain contains 3 multisubunit complexes succinate dehydrogenase (complex II, CII), ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III, CIII) and cytochrome c oxidase (complex IV, CIV), that cooperate to transfer electrons derived from NADH and succinate to molecular oxygen, creating an electrochemical gradient over t

Mitochondrion inner membrane

Mitochondrial complex IV deficiency, nuclear type 7

An autosomal recessive mitochondrial disorder characterized by encephalomyopathy resulting in variable clinical manifestations. Features include muscle weakness, gait disturbances, neurodegeneration, cognitive decline, metabolic acidosis, feeding difficulties, poor overall growth, cortical visual impairment, and hypertrophic cardiomyopathy. Serum lactate levels are increased. Patient tissues show decreased levels and activity of mitochondrial respiratory complex IV.

Converts protoheme IX and farnesyl diphosphate to heme O

Mitochondrion membrane

Mitochondrial complex IV deficiency, nuclear type 3

An autosomal recessive mitochondrial disorder characterized by cytochrome c oxidase deficiency. Clinical features include muscle weakness, hypotonia, ataxia, ptosis, metabolic acidosis, poor feeding, delayed motor development, anemia, sensorineural hearing loss, and cardiomyopathy.

Component of the MITRAC (mitochondrial translation regulation assembly intermediate of cytochrome c oxidase complex) complex, that regulates cytochrome c oxidase assembly

Mitochondrion inner membrane

Mitochondrial complex IV deficiency, nuclear type 1

An autosomal recessive disorder of the mitochondrial respiratory chain characterized by early-onset, rapidly progressive encephalopathy, neurodegeneration, and loss of motor and cognitive skills. Affected individuals show hypotonia, failure to thrive, loss of the ability to sit or walk, poor communication, poor eye contact, oculomotor abnormalities, as well as deafness, ataxia, tremor, and brisk tendon reflexes. Brain imaging shows bilateral symmetric lesions in the basal ganglia. Lactate levels in serum and cerebrospinal fluid are increased. Patient tissues show decreased levels and activity of mitochondrial respiratory complex IV. Death in childhood may occur, often due to central respiratory failure.

Flavoprotein (FP) subunit of succinate dehydrogenase (SDH) that is involved in complex II of the mitochondrial electron transport chain and is responsible for transferring electrons from succinate to ubiquinone (coenzyme Q) (PubMed:10746566, PubMed:24781757). SDH also oxidizes malate to the non-canonical enol form of oxaloacetate, enol-oxaloacetate (By similarity). Enol-oxaloacetate, which is a potent inhibitor of the succinate dehydrogenase activity, is further isomerized into keto-oxaloacetate

Mitochondrion inner membrane

Mitochondrial complex II deficiency, nuclear type 1

A disorder of the mitochondrial respiratory chain with heterogeneous clinical manifestations. Clinical features include psychomotor regression in infants, poor growth with lack of speech development, severe spastic quadriplegia, dystonia, progressive leukoencephalopathy, muscle weakness, exercise intolerance, cardiomyopathy. Some patients manifest Leigh syndrome or Kearns-Sayre syndrome. MC2DN1 inheritance is autosomal recessive.

Core subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I) which catalyzes electron transfer from NADH through the respiratory chain, using ubiquinone as an electron acceptor (PubMed:22036843, PubMed:28031252, PubMed:30922174). Essential for the catalytic activity of complex I (PubMed:22036843, PubMed:30922174). Essential for the assembly of complex I (By similarity). Redox-sensitive, critical component of the oxygen-sensing pathway in the pulmonary vasculature w

Mitochondrion inner membrane

Mitochondrial complex I deficiency, nuclear type 6

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN6 transmission pattern is consistent with autosomal recessive inheritance.

Accessory subunit of the mitochondrial membrane respiratory chain NADH dehydrogenase (Complex I), that is believed not to be involved in catalysis (PubMed:27626371, PubMed:32385911, PubMed:33153867). Complex I functions in the transfer of electrons from NADH to the respiratory chain (PubMed:27626371). The immediate electron acceptor for the enzyme is believed to be ubiquinone (PubMed:27626371)

Mitochondrion inner membraneMitochondrion intermembrane spaceMitochondrion

Mitochondrial complex I deficiency, nuclear type 37

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN37 features include developmental delay, cerebral atrophy, epilepsy, growth retardation, congenital myopathy with disproportion of fibers, and severely decreased activity of complex I. MC1DN37 transmission pattern is consistent with autosomal recessive inheritance.

Involved in the assembly of mitochondrial NADH:ubiquinone oxidoreductase complex (complex I) at early stages. May play a role in the biogenesis of complex I subunit MT-ND1

Mitochondrion inner membraneCytoplasmNucleus

Mitochondrial complex I deficiency, nuclear type 17

A form of mitochondrial complex I deficiency, the most common biochemical signature of mitochondrial disorders, a group of highly heterogeneous conditions characterized by defective oxidative phosphorylation, which collectively affects 1 in 5-10000 live births. Clinical disorders have variable severity, ranging from lethal neonatal disease to adult-onset neurodegenerative disorders. Phenotypes include macrocephaly with progressive leukodystrophy, non-specific encephalopathy, cardiomyopathy, myopathy, liver disease, Leigh syndrome, Leber hereditary optic neuropathy, and some forms of Parkinson disease. MC1DN17 transmission pattern is consistent with autosomal recessive inheritance.

S-adenosyl-L-methionine-dependent 2'-O-ribose methyltransferase that catalyzes the formation of 2'-O-methyluridine at position 1369 (Um1369) in the 16S mitochondrial large subunit ribosomal RNA (mtLSU rRNA), a universally conserved modification in the peptidyl transferase domain of the mtLSU rRNA (PubMed:25009282, PubMed:25074936, PubMed:35177605). This activity may require prior 2'-O-methylguanosine modification at position 1370 (Gm1370) by MRM3 (PubMed:35177605). Essential for late-stage assem

Mitochondrion

Mitochondrial DNA depletion syndrome 17

An autosomal recessive mitochondrial disorder characterized by childhood onset of rapidly progressive encephalopathy, stroke-like episodes, lactic acidosis, hypocitrullinemia, multiple defects of oxidative phosphorylation, mitochondrial complex I and IV deficiency, and reduced mtDNA copy number.

ADP:ATP antiporter that mediates import of ADP into the mitochondrial matrix for ATP synthesis, and export of ATP out to fuel the cell (PubMed:21586654, PubMed:27693233, PubMed:23173940, PubMed:30046662). Cycles between the cytoplasmic-open state (c-state) and the matrix-open state (m-state): operates by the alternating access mechanism with a single substrate-binding site intermittently exposed to either the cytosolic (c-state) or matrix (m-state) side of the inner mitochondrial membrane (By si

Mitochondrion inner membraneMembrane

Progressive external ophthalmoplegia with mitochondrial DNA deletions, autosomal dominant, 2

A disorder characterized by progressive weakness of ocular muscles and levator muscle of the upper eyelid. In a minority of cases, it is associated with skeletal myopathy, which predominantly involves axial or proximal muscles and which causes abnormal fatigability and even permanent muscle weakness. Ragged-red fibers and atrophy are found on muscle biopsy. A large proportion of chronic ophthalmoplegias are associated with other symptoms, leading to a multisystemic pattern of this disease. Additional symptoms are variable, and may include cataracts, hearing loss, sensory axonal neuropathy, ataxia, depression, hypogonadism, and parkinsonism.