IDH3G

Last updated
IDH3G
Identifiers
Aliases IDH3G , H-IDHG, isocitrate dehydrogenase 3 (NAD(+)) gamma, isocitrate dehydrogenase (NAD(+)) 3 gamma, isocitrate dehydrogenase (NAD(+)) 3 non-catalytic subunit gamma
External IDs OMIM: 300089 MGI: 1099463 HomoloGene: 55803 GeneCards: IDH3G
Orthologs
SpeciesHumanMouse
Entrez
Ensembl
UniProt
RefSeq (mRNA)

NM_174869
NM_004135

NM_008323
NM_001356356

RefSeq (protein)

NP_004126
NP_777358

NP_032349
NP_001343285

Location (UCSC) Chr X: 153.79 – 153.79 Mb Chr X: 72.82 – 72.83 Mb
PubMed search [3] [4]
Wikidata
View/Edit Human View/Edit Mouse

Isocitrate dehydrogenase [NAD] subunit gamma, mitochondrial is an enzyme that in humans is encoded by the IDH3G gene. [5] [6]

Contents

Isocitrate dehydrogenases (IDHs) catalyze the oxidative decarboxylation of isocitrate to 2-oxoglutarate. These enzymes belong to two distinct subclasses, one of which utilizes NAD(+) as the electron acceptor and the other NADP(+). Five isocitrate dehydrogenases have been reported: three NAD(+)-dependent isocitrate dehydrogenases, which localize to the mitochondrial matrix, and two NADP(+)-dependent isocitrate dehydrogenases, one of which is mitochondrial and the other predominantly cytosolic. NAD(+)-dependent isocitrate dehydrogenases catalyze the allosterically regulated rate-limiting step of the tricarboxylic acid cycle. Each isozyme is a heterotetramer that is composed of two alpha subunits, one beta subunit, and one gamma subunit. The protein encoded by this gene is the gamma subunit of one isozyme of NAD(+)-dependent isocitrate dehydrogenase. This gene is a candidate gene for periventricular heterotopia. Several alternatively spliced transcript variants of this gene have been described, but only some of their full length natures have been determined. [provided by RefSeq, Jul 2008] [6]

Structure

IDH3 is one of three isocitrate dehydrogenase isozymes, the other two being IDH1 and IDH2, and encoded by one of five isocitrate dehydrogenase genes, which are IDH1, IDH2 , IDH3A , IDH3B , and IDH3G. [7] The genes IDH3A, IDH3B, and IDH3G encode subunits of IDH3, which is a heterotetramer composed of two 37-kDa α subunits (IDH3α), one 39-kDa β subunit (IDH3β), and one 39-kDa γ subunit (IDH3γ), each with distinct isoelectric points. [8] [9] [10] Alignment of their amino acid sequences reveals ~40% identity between IDH3α and IDH3β, ~42% identity between IDH3α and IDH3γ, and an even closer identity of 53% between IDH3β and IDH3γ, for an overall 34% identity and 23% similarity across all three subunit types. [9] [10] [11] [12] Notably, Arg88 in IDH3α is essential for IDH3 catalytic activity, whereas the equivalent Arg99 in IDH3β and Arg97 in IDH3γ are largely involved in the enzyme's allosteric regulation by ADP and NAD. [11] Thus, it is possible that these subunits arose from gene duplication of a common ancestral gene, and the original catalytic Arg residue were adapted to allosteric functions in the β- and γ-subunits. [9] [11] Likewise, Asp181 in IDH3α is essential for catalysis, while the equivalent Asp192 in IDH3β and Asp190 in IDH3γ enhance NAD- and Mn2+-binding. [9] Since the oxidative decarboxylation catalyzed by IDH3 requires binding of NAD, Mn2+, and the substrate isocitrate, all three subunits participate in the catalytic reaction. [10] [11] Moreover, studies of the enzyme in pig heart reveal that the αβ and αγ dimers constitute two binding sites for each of its ligands, including isocitrate, Mn2+, and NAD, in one IDH3 tetramer. [9] [10]

Function

As an isocitrate dehydrogenase, IDH3 catalyzes the irreversible oxidative decarboxylation of isocitrate to yield α-ketoglutarate (α-KG) and CO2 as part of the TCA cycle in glucose metabolism. [8] [9] [10] [11] [13] This step also allows for the concomitant reduction of NAD+ to NADH, which is then used to generate ATP through the electron transport chain. Notably, IDH3 relies on NAD+ as its electron acceptor, as opposed to NADP+ like IDH1 and IDH2. [8] [9] IDH3 activity is regulated by the energy needs of the cell: when the cell requires energy, IDH3 is activated by ADP; and when energy is no longer required, IDH3 is inhibited by ATP and NADH. [9] [10] This allosteric regulation allows IDH3 to function as a rate-limiting step in the TCA cycle. [13] [14] Within cells, IDH3 and its subunits have been observed to localize to the mitochondria. [9] [10] [13]

Clinical Significance

The IDH3G gene may be involved in drug resistance in gastric cancer. [15]

Interactive pathway map

Click on genes, proteins and metabolites below to link to respective articles. [§ 1]

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TCACycle WP78.png Go to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to HMDBGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to articleGo to article
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TCACycle_WP78 edit
  1. The interactive pathway map can be edited at WikiPathways: "TCACycle_WP78".

See also

Related Research Articles

<span class="mw-page-title-main">Isocitrate dehydrogenase</span> Class of enzymes

Isocitrate dehydrogenase (IDH) (EC 1.1.1.42) and (EC 1.1.1.41) is an enzyme that catalyzes the oxidative decarboxylation of isocitrate, producing alpha-ketoglutarate (α-ketoglutarate) and CO2. This is a two-step process, which involves oxidation of isocitrate (a secondary alcohol) to oxalosuccinate (a ketone), followed by the decarboxylation of the carboxyl group beta to the ketone, forming alpha-ketoglutarate. In humans, IDH exists in three isoforms: IDH3 catalyzes the third step of the citric acid cycle while converting NAD+ to NADH in the mitochondria. The isoforms IDH1 and IDH2 catalyze the same reaction outside the context of the citric acid cycle and use NADP+ as a cofactor instead of NAD+. They localize to the cytosol as well as the mitochondrion and peroxisome.

<span class="mw-page-title-main">Isocitrate dehydrogenase (NAD+)</span> Enzyme

Isocitrate dehydrogenase (NAD+) (EC 1.1.1.41, isocitric dehydrogenase, beta-ketoglutaric-isocitric carboxylase, isocitric acid dehydrogenase, NAD dependent isocitrate dehydrogenase, NAD isocitrate dehydrogenase, NAD-linked isocitrate dehydrogenase, NAD-specific isocitrate dehydrogenase, NAD isocitric dehydrogenase, isocitrate dehydrogenase (NAD), IDH (ambiguous), nicotinamide adenine dinucleotide isocitrate dehydrogenase) is an enzyme with systematic name isocitrate:NAD+ oxidoreductase (decarboxylating). This enzyme catalyses the following chemical reaction

<span class="mw-page-title-main">HADHA</span> Protein-coding gene in the species Homo sapiens

Trifunctional enzyme subunit alpha, mitochondrial also known as hydroxyacyl-CoA dehydrogenase/3-ketoacyl-CoA thiolase/enoyl-CoA hydratase, alpha subunit is a protein that in humans is encoded by the HADHA gene. Mutations in HADHA have been associated with trifunctional protein deficiency or long-chain 3-hydroxyacyl-coenzyme A dehydrogenase deficiency.

<span class="mw-page-title-main">HADHB</span> Protein-coding gene in the species Homo sapiens

Trifunctional enzyme subunit beta, mitochondrial (TP-beta) also known as 3-ketoacyl-CoA thiolase, acetyl-CoA acyltransferase, or beta-ketothiolase is an enzyme that in humans is encoded by the HADHB gene.

<span class="mw-page-title-main">GNB1</span> Protein-coding gene in the species Homo sapiens

Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-1 is a protein that in humans is encoded by the GNB1 gene.

<span class="mw-page-title-main">PRKAG2</span> Protein-coding gene in the species Homo sapiens

5'-AMP-activated protein kinase subunit gamma-2 is an enzyme that in humans is encoded by the PRKAG2 gene.

<span class="mw-page-title-main">GNB2</span> Protein-coding gene in the species Homo sapiens

Guanine nucleotide-binding protein G(I)/G(S)/G(T) subunit beta-2 is a protein that in humans is encoded by the GNB2 gene.

<span class="mw-page-title-main">EIF2S2</span> Protein-coding gene in the species Homo sapiens

Eukaryotic translation initiation factor 2 subunit 2 (eIF2β) is a protein that in humans is encoded by the EIF2S2 gene.

<span class="mw-page-title-main">Phosphoglycerate dehydrogenase</span> Metabolic enzyme PHGDH

Phosphoglycerate dehydrogenase (PHGDH) is an enzyme that catalyzes the chemical reactions

<span class="mw-page-title-main">BCKDHB</span> Protein-coding gene in the species Homo sapiens

2-Oxoisovalerate dehydrogenase subunit beta, mitochondrial is an enzyme that in humans is encoded by the BCKDHB gene.

<span class="mw-page-title-main">KCNAB1</span> Protein-coding gene in the species Homo sapiens

Voltage-gated potassium channel subunit beta-1 is a protein that in humans is encoded by the KCNAB1 gene.

<span class="mw-page-title-main">GNGT1</span> Protein-coding gene in the species Homo sapiens

Guanine nucleotide-binding protein G(T) subunit gamma-T1 is a protein that in humans is encoded by the GNGT1 gene.

<span class="mw-page-title-main">IDH3A</span> Protein-coding gene in the species Homo sapiens

Isocitrate dehydrogenase [NAD] subunit alpha, mitochondrial (IDH3α) is an enzyme that in humans is encoded by the IDH3A gene.

<span class="mw-page-title-main">IDH2</span>

Isocitrate dehydrogenase [NADP], mitochondrial is an enzyme that in humans is encoded by the IDH2 gene.

<span class="mw-page-title-main">CACNB3</span> Protein-coding gene in humans

Voltage-dependent L-type calcium channel subunit beta-3 is a protein that in humans is encoded by the CACNB3 gene.

<span class="mw-page-title-main">IDH3B</span> Protein-coding gene in the species Homo sapiens

Isocitrate dehydrogenase [NAD] subunit beta, mitochondrial is an enzyme that in humans is encoded by the IDH3B gene.

<span class="mw-page-title-main">Malate dehydrogenase 2</span> Enzyme that oxidizes malate to oxaloacetate in Krebs cycle

Malate dehydrogenase, mitochondrial also known as malate dehydrogenase 2 is an enzyme that in humans is encoded by the MDH2 gene.

<span class="mw-page-title-main">Pyruvate dehydrogenase (lipoamide) alpha 2</span> Protein-coding gene in the species Homo sapiens

Pyruvate dehydrogenase (lipoamide) alpha 2, also known as pyruvate dehydrogenase E1 component subunit alpha, testis-specific form, mitochondrial or PDHE1-A type II, is an enzyme that in humans is encoded by the PDHA2 gene.

<span class="mw-page-title-main">Pyruvate dehydrogenase (lipoamide) beta</span> Protein-coding gene in the species Homo sapiens

Pyruvate dehydrogenase (lipoamide) beta, also known as pyruvate dehydrogenase E1 component subunit beta, mitochondrial or PDHE1-B is an enzyme that in humans is encoded by the PDHB gene. The pyruvate dehydrogenase (PDH) complex is a nuclear-encoded mitochondrial multienzyme complex that catalyzes the overall conversion of pyruvate to acetyl-CoA and CO2, and provides the primary link between glycolysis and the tricarboxylic acid (TCA) cycle. The PDH complex is composed of multiple copies of three enzymatic components: pyruvate dehydrogenase (E1), dihydrolipoamide acetyltransferase (E2) and lipoamide dehydrogenase (E3). The E1 enzyme is a heterotetramer of two alpha and two beta subunits. This gene encodes the E1 beta subunit. Mutations in this gene are associated with pyruvate dehydrogenase E1-beta deficiency.

<span class="mw-page-title-main">IDH1</span> Protein-coding gene in the species Homo sapiens

Isocitrate dehydrogenase 1 (NADP+), soluble is an enzyme that in humans is encoded by the IDH1 gene on chromosome 2. Isocitrate dehydrogenases catalyze the oxidative decarboxylation of isocitrate to 2-oxoglutarate. These enzymes belong to two distinct subclasses, one of which uses NAD+ as the electron acceptor and the other NADP+. Five isocitrate dehydrogenases have been reported: three NAD+-dependent isocitrate dehydrogenases, which localize to the mitochondrial matrix, and two NADP+-dependent isocitrate dehydrogenases, one of which is mitochondrial and the other predominantly cytosolic. Each NADP+-dependent isozyme is a homodimer. The protein encoded by this gene is the NADP+-dependent isocitrate dehydrogenase found in the cytoplasm and peroxisomes. It contains the PTS-1 peroxisomal targeting signal sequence. The presence of this enzyme in peroxisomes suggests roles in the regeneration of NADPH for intraperoxisomal reductions, such as the conversion of 2,4-dienoyl-CoAs to 3-enoyl-CoAs, as well as in peroxisomal reactions that consume 2-oxoglutarate, namely the alpha-hydroxylation of phytanic acid. The cytoplasmic enzyme serves a significant role in cytoplasmic NADPH production. Alternatively spliced transcript variants encoding the same protein have been found for this gene. [provided by RefSeq, Sep 2013]

References

  1. 1 2 3 GRCh38: Ensembl release 89: ENSG00000067829 - Ensembl, May 2017
  2. 1 2 3 GRCm38: Ensembl release 89: ENSMUSG00000002010 - Ensembl, May 2017
  3. "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. Brenner V, Nyakatura G, Rosenthal A, Platzer M (November 1997). "Genomic organization of two novel genes on human Xq28: compact head to head arrangement of IDH gamma and TRAP delta is conserved in rat and mouse". Genomics. 44 (1): 8–14. doi:10.1006/geno.1997.4822. PMID   9286695.
  6. 1 2 "Entrez Gene: IDH3G isocitrate dehydrogenase 3 (NAD+) gamma".
  7. Dimitrov L, Hong CS, Yang C, Zhuang Z, Heiss JD (2015). "New developments in the pathogenesis and therapeutic targeting of the IDH1 mutation in glioma". International Journal of Medical Sciences. 12 (3): 201–13. doi:10.7150/ijms.11047. PMC   4323358 . PMID   25678837.
  8. 1 2 3 Zeng, L; Morinibu, A; Kobayashi, M; Zhu, Y; Wang, X; Goto, Y; Yeom, CJ; Zhao, T; Hirota, K; Shinomiya, K; Itasaka, S; Yoshimura, M; Guo, G; Hammond, EM; Hiraoka, M; Harada, H (3 September 2015). "Aberrant IDH3α expression promotes malignant tumor growth by inducing HIF-1-mediated metabolic reprogramming and angiogenesis". Oncogene. 34 (36): 4758–66. doi: 10.1038/onc.2014.411 . PMID   25531325.
  9. 1 2 3 4 5 6 7 8 9 Bzymek, KP; Colman, RF (8 May 2007). "Role of alpha-Asp181, beta-Asp192, and gamma-Asp190 in the distinctive subunits of human NAD-specific isocitrate dehydrogenase". Biochemistry. 46 (18): 5391–7. doi:10.1021/bi700061t. PMID   17432878.
  10. 1 2 3 4 5 6 7 Soundar, S; O'hagan, M; Fomulu, KS; Colman, RF (28 July 2006). "Identification of Mn2+-binding aspartates from alpha, beta, and gamma subunits of human NAD-dependent isocitrate dehydrogenase". The Journal of Biological Chemistry. 281 (30): 21073–81. doi: 10.1074/jbc.m602956200 . PMID   16737955.
  11. 1 2 3 4 5 Soundar, S; Park, JH; Huh, TL; Colman, RF (26 December 2003). "Evaluation by mutagenesis of the importance of 3 arginines in alpha, beta, and gamma subunits of human NAD-dependent isocitrate dehydrogenase". The Journal of Biological Chemistry. 278 (52): 52146–53. doi: 10.1074/jbc.m306178200 . PMID   14555658.
  12. Dange, M; Colman, RF (2 July 2010). "Each conserved active site tyr in the three subunits of human isocitrate dehydrogenase has a different function". The Journal of Biological Chemistry. 285 (27): 20520–5. doi: 10.1074/jbc.m110.115386 . PMC   2898308 . PMID   20435888.
  13. 1 2 3 Huh TL, Kim YO, Oh IU, Song BJ, Inazawa J (May 1997). "Assignment of the human mitochondrial NAD+ -specific isocitrate dehydrogenase alpha subunit (IDH3A) gene to 15q25.1→q25.2by in situ hybridization". Genomics. 32 (2): 295–6. doi:10.1006/geno.1996.0120. PMID   8833160.
  14. Yoshimi, N; Futamura, T; Bergen, SE; Iwayama, Y; Ishima, T; Sellgren, C; Ekman, CJ; Jakobsson, J; Pålsson, E; Kakumoto, K; Ohgi, Y; Yoshikawa, T; Landén, M; Hashimoto, K (19 January 2016). "Cerebrospinal fluid metabolomics identifies a key role of isocitrate dehydrogenase in bipolar disorder: evidence in support of mitochondrial dysfunction hypothesis". Molecular Psychiatry. 21 (11): 1504–1510. doi:10.1038/mp.2015.217. PMC   5078854 . PMID   26782057.
  15. Zhou, J; Yong, WP; Yap, CS; Vijayaraghavan, A; Sinha, RA; Singh, BK; Xiu, S; Manesh, S; Ngo, A; Lim, A; Ang, C; Xie, C; Wong, FY; Lin, SJ; Wan, WK; Tan, IB; Flotow, H; Tan, P; Lim, KH; Yen, PM; Goh, LK (April 2015). "An integrative approach identified genes associated with drug response in gastric cancer". Carcinogenesis. 36 (4): 441–51. doi: 10.1093/carcin/bgv014 . PMID   25742747.

Further reading