IQCB1 Gene
IQ Motif Containing B1
Gene Information Card
| Symbol | IQCB1 |
|---|---|
| Full Name | IQ Motif Containing B1 |
| Gene Type | Protein coding |
| Chromosomal Location | 3q13.33 |
| NCBI Gene ID | 9657 ncbi.nlm.nih.gov/gene/9657 |
| Ensembl ID | ENSG00000173226 |
| UniProt ID | O75128 |
| OMIM ID | 609237 |
| HGNC ID | 28959 |
| Aliases | NPHP5, CILD30, SLSN5, IQCB1 |
Description
The IQCB1 gene encodes nephrocystin-5, a protein containing IQ calmodulin-binding motifs. It is essential for primary cilia function and localizes to the centrosome and ciliary transition zone. Mutations in IQCB1 cause nephronophthisis type 5 (NPHP5) and Senior-Løken syndrome type 5 (SLSN5), characterized by renal cystic disease and retinal degeneration.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Nephronophthisis 5 (NPHP5) | Loss of function of nephrocystin-5 disrupts ciliary signaling and renal tubular integrity, leading to fibrosis and cyst formation. | ClinVar, OMIM |
| Senior-Løken syndrome 5 (SLSN5) | Defective ciliary protein complex in photoreceptor cells and renal tubules causes both retinal degeneration and nephronophthisis. | ClinVar, OMIM |
| Joubert syndrome (rare) | Biallelic IQCB1 mutations impair cerebellar and renal development via ciliary dysfunction. | ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Kidney | 12.5 | Medium |
| Testis | 9.8 | Medium |
| Retina | 8.2 | Medium |
| Brain | 6.1 | Low |
| Liver | 3.4 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK 293 | 15.2 | Embryonic kidney cell line |
| ARPE-19 | 11.0 | Retinal pigment epithelium |
| HeLa | 7.8 | Cervical carcinoma |
| HepG2 | 4.5 | Hepatocellular carcinoma |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.1090C>T (p.Arg364*) | Nonsense | ~15% of NPHP5 cases | Premature stop, loss of function |
| c.566G>A (p.Trp189*) | Nonsense | ~10% of NPHP5 cases | Premature stop, loss of function |
| c.1465C>T (p.Arg489Trp) | Missense | Rare | Impaired protein stability |
| c.1921C>T (p.Arg641*) | Nonsense | ~5% of NPHP5 cases | Premature stop, loss of function |
Mutation functional classification
Loss of Function (LOF)
Most IQCB1 mutations are nonsense or frameshift, leading to truncated nephrocystin-5 and complete loss of ciliary function.
Gain of Function (GOF)
No gain-of-function mutations reported.
Dominant Negative (DN)
No dominant-negative mutations reported; disease is autosomal recessive.
View complete mutation data：
Gene Ontology (GO)
| • calmodulin binding (GO:0005516) | • cilium (GO:0005929) |
| • ciliary basal body (GO:0036064) | • centrosome (GO:0005813) |
| • cytoplasm (GO:0005737) | • protein binding (GO:0005515) |
Pathways
• Ciliopathy pathway (Reactome R-HSA-5620920)
• Primary cilium assembly (Reactome R-HSA-5620916)
Protein Summary
Nephrocystin-5 (NPHP5) is a 598-amino-acid protein with three IQ calmodulin-binding domains. It interacts with retinitis pigmentosa GTPase regulator (RPGR) and other ciliary proteins to maintain ciliary structure and function. Defects lead to renal fibrosis and photoreceptor degeneration.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| IQCB1 Knockout HEK293 Cell Line | EDJ-KQ6680 | Human | 9657 | Details Get a Quote |
| IQCB1 Knockout A-549 Cell Line | EDJ-KQ31011 | Human | 9657 | Details Get a Quote |
| IQCB1 Knockout HCT 116 Cell Line | EDJ-KQ31012 | Human | 9657 | Details Get a Quote |
| IQCB1 Knockout HeLa Cell Line | EDJ-KQ31013 | Human | 9657 | Details Get a Quote |
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