IDH3B
Isocitrate Dehydrogenase 3 (NAD+) Beta Subunit
Gene Information Card
| Symbol | IDH3B |
|---|---|
| Full Name | Isocitrate Dehydrogenase (NAD(+)) 3 Beta |
| Gene Type | Protein coding |
| Chromosomal Location | 20p13 |
| NCBI Gene ID | 3420 ncbi.nlm.nih.gov/gene/3420 |
| Ensembl ID | ENSG00000101365 |
| UniProt ID | O43837 |
| OMIM ID | 604526 |
| HGNC ID | 5385 |
| Aliases | H-IDHB, IDH3BETA |
Description
IDH3B encodes the beta subunit of the mitochondrial NAD+-dependent isocitrate dehydrogenase (IDH3), a key enzyme in the tricarboxylic acid (TCA) cycle that catalyzes the oxidative decarboxylation of isocitrate to alpha-ketoglutarate, producing NADH. The enzyme is a heterotetramer composed of two alpha, one beta, and one gamma subunit. Mutations in IDH3B are associated with metabolic disorders and have been implicated in cancer metabolism.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Retinitis Pigmentosa 46 | Loss-of-function mutations impair TCA cycle, leading to retinal degeneration | OMIM #612572; ClinVar |
| Metabolic Syndrome | Altered IDH3B expression affects NADH production and mitochondrial function | PubMed studies |
| Cancer (various) | Somatic mutations and altered expression influence oncometabolite levels and cell proliferation | COSMIC; PubMed |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Heart | 12.5 | High |
| Skeletal Muscle | 10.2 | High |
| Liver | 8.1 | Medium |
| Kidney | 7.9 | Medium |
| Brain | 6.5 | Medium |
| Lung | 4.3 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 14.0 | High expression |
| HeLa | 11.5 | High expression |
| HepG2 | 9.8 | Medium expression |
| A549 | 7.2 | Medium expression |
| K562 | 5.1 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.260G>A (p.Arg87Gln) | Missense | Rare | Reduced enzyme activity; associated with retinitis pigmentosa |
| c.418C>T (p.Arg140Trp) | Missense | Rare | Impaired subunit assembly; loss of function |
| c.1A>G (p.Met1Val) | Start loss | Very rare | Complete loss of protein expression |
Mutation functional classification
Loss of Function (LOF)
Missense and start-loss mutations reduce or abolish IDH3 activity, impairing TCA cycle flux.
Gain of Function (GOF)
Not reported for IDH3B.
Dominant Negative (DN)
Some missense mutations may interfere with heterotetramer assembly, exerting dominant-negative effects.
View complete mutation data：
Gene Ontology (GO)
| • isocitrate dehydrogenase (NAD+) activity (GO:0004449) | • tricarboxylic acid cycle (GO:0006099) |
| • mitochondrion (GO:0005739) | • NAD binding (GO:0051287) |
| • catalytic activity (GO:0003824) |
Pathways
• TCA cycle (KEGG: hsa00020)
• Metabolic pathways (KEGG: hsa01100)
• Citrate cycle (Reactome: R-HSA-71403)
Protein Summary
The IDH3B protein (UniProt O43837) is 369 amino acids long and localizes to the mitochondrial matrix. It forms a heterotetrameric complex with IDH3A and IDH3G subunits to catalyze the NAD+-dependent conversion of isocitrate to alpha-ketoglutarate. The beta subunit is essential for enzyme stability and catalytic efficiency. Mutations in IDH3B lead to reduced enzymatic activity and are linked to retinal degeneration and metabolic dysregulation.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| IDH3B Knockout HEK293 Cell Line | EDJ-KQ4964 | Human | 3420 | Details Get a Quote |
| IDH3B Knockout A-549 Cell Line | EDJ-KQ27839 | Human | 3420 | Details Get a Quote |
| IDH3B Knockout HCT 116 Cell Line | EDJ-KQ27840 | Human | 3420 | Details Get a Quote |
| IDH3B Knockout HeLa Cell Line | EDJ-KQ27841 | Human | 3420 | Details Get a Quote |
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