IMPDH1 Gene: Inosine Monophosphate Dehydrogenase 1
Key enzyme in guanine nucleotide biosynthesis, associated with retinitis pigmentosa and cancer
Gene Information Card
| Symbol | IMPDH1 |
|---|---|
| Full Name | Inosine Monophosphate Dehydrogenase 1 |
| Gene Type | Protein coding |
| Chromosomal Location | 7q32.1 |
| NCBI Gene ID | 3614 ncbi.nlm.nih.gov/gene/3614 |
| Ensembl ID | ENSG00000106348 |
| UniProt ID | P20839 |
| OMIM ID | 146690 |
| HGNC ID | 6052 |
| Aliases | IMPD, IMPD1, IMPDH-I |
Description
IMPDH1 encodes inosine monophosphate dehydrogenase 1, a rate-limiting enzyme in the de novo synthesis of guanine nucleotides. It catalyzes the conversion of inosine 5'-phosphate (IMP) to xanthosine 5'-phosphate (XMP) using NAD+ as a cofactor. This enzyme is essential for cellular proliferation and is a target for immunosuppressive and antiviral drugs. Mutations in IMPDH1 are associated with autosomal dominant retinitis pigmentosa (RP10) and may contribute to cancer cell growth.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Retinitis pigmentosa 10 (RP10) | Dominant-negative or gain-of-function mutations in IMPDH1 disrupt retinal cell homeostasis, leading to photoreceptor degeneration. | ClinVar, OMIM |
| Retinitis pigmentosa (general) | Missense and splice-site variants impair enzyme activity or stability, causing progressive vision loss. | ClinVar, OMIM |
| Cancer (various) | Overexpression of IMPDH1 supports increased guanine nucleotide synthesis required for rapid tumor cell proliferation. | COSMIC, NCBI |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Retina | 12.5 | High |
| Testis | 10.2 | High |
| Lymph node | 8.1 | Medium |
| Brain | 6.3 | Medium |
| Liver | 4.7 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | 15.3 | High expression |
| HeLa | 12.8 | High expression |
| K562 | 9.4 | Medium expression |
| MCF7 | 7.1 | Medium expression |
| HepG2 | 5.6 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.926G>A (p.Arg309His) | Missense | 0.01% in general population | Dominant-negative; associated with RP10 |
| c.868C>T (p.Arg290Trp) | Missense | <0.01% | Gain-of-function; linked to retinitis pigmentosa |
| c.1336G>A (p.Asp446Asn) | Missense | 0.005% | Loss-of-function; reduced enzyme activity |
| c.1124T>C (p.Leu375Pro) | Missense | <0.001% | Dominant-negative; severe RP phenotype |
Mutation functional classification
Loss of Function (LOF)
Rare missense mutations (e.g., p.Asp446Asn) reduce catalytic activity, impairing guanine nucleotide synthesis.
Gain of Function (GOF)
Mutations such as p.Arg290Trp increase enzyme activity, leading to nucleotide imbalance and retinal toxicity.
Dominant Negative (DN)
Common RP10 mutations (e.g., p.Arg309His) produce a defective enzyme that interferes with wild-type function, causing photoreceptor death.
View complete mutation data：
Gene Ontology (GO)
| • IMP dehydrogenase activity (GO:0003938) | • GMP biosynthetic process (GO:0006177) |
| • ATP binding (GO:0005524) | • cytoplasm (GO:0005737) |
| • cytosol (GO:0005829) |
Pathways
• Purine metabolism (KEGG: hsa00230)
• Guanine nucleotide biosynthesis (Reactome: R-HSA-73817)
Protein Summary
IMPDH1 is a 514-amino acid protein that forms a homotetramer. Each subunit contains a TIM barrel domain and a CBS domain. The enzyme uses NAD+ to oxidize IMP to XMP, a critical step in guanine nucleotide synthesis. It is highly expressed in proliferating cells and retina. Mutations in the CBS domain are frequently associated with retinitis pigmentosa. The protein is a target for mycophenolic acid, an immunosuppressant.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| IMPDH1 Knockout HEK293 Cell Line | EDJ-KQ4998 | Human | 3614 | Details Get a Quote |
| IMPDH1 Knockout A-549 Cell Line | EDJ-KQ27895 | Human | 3614 | Details Get a Quote |
| IMPDH1 Knockout HCT 116 Cell Line | EDJ-KQ27896 | Human | 3614 | Details Get a Quote |
| IMPDH1 Knockout HeLa Cell Line | EDJ-KQ27897 | Human | 3614 | Details Get a Quote |
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