CPAP (CENPJ) Gene
Centrosomal Protein Required for Centriole Duplication and Microcephaly Pathogenesis
Gene Information Card
| Symbol | CPAP |
|---|---|
| Full Name | Centrosomal Protein (CENPJ) |
| Gene Type | Protein coding |
| Chromosomal Location | 13q12.12-q12.13 |
| NCBI Gene ID | 55835 ncbi.nlm.nih.gov/gene/55835 |
| Ensembl ID | ENSG00000151849 |
| UniProt ID | Q9HC77 |
| OMIM ID | 609279 |
| HGNC ID | 17272 |
| Aliases | CENPJ, LAP, LIP1, MCPH6, SCKL4, Sas-4 |
Description
The CPAP gene (also known as CENPJ) encodes a centrosomal protein essential for centriole duplication and microtubule organization. It is a core component of the centrosome and is required for proper cell division. Mutations in CPAP cause autosomal recessive primary microcephaly type 6 (MCPH6) and Seckel syndrome type 4 (SCKL4), characterized by reduced brain size and growth retardation.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Primary microcephaly 6 (MCPH6) | Loss-of-function mutations impair centriole duplication, leading to reduced neural progenitor cell proliferation | OMIM #608716 |
| Seckel syndrome 4 (SCKL4) | Biallelic mutations disrupt centrosome function, causing microcephaly and dwarfism | OMIM #613676 |
| Cancer (various) | Overexpression or amplification of CPAP may promote centrosome amplification and aneuploidy | COSMIC, ClinVar |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Testis | 15.2 | Medium |
| Brain (cerebral cortex) | 12.8 | Medium |
| Bone marrow | 10.5 | Medium |
| Lung | 8.3 | Low |
| Liver | 6.1 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HeLa | 18.5 | High expression |
| HEK293 | 14.2 | Medium expression |
| U2OS | 12.0 | Medium expression |
| MCF7 | 9.8 | Low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.370C>T (p.Arg124*) | Nonsense | Rare | Loss of function; truncation of CPAP protein |
| c.940G>A (p.Gly314Arg) | Missense | Rare | Impaired centriole duplication |
| c.1234delC (p.Leu412Trpfs*5) | Frameshift | Rare | Loss of function; premature termination |
| c.1681C>T (p.Arg561Trp) | Missense | Rare | Reduced protein stability |
Mutation functional classification
Loss of Function (LOF)
Nonsense, frameshift, and splice-site mutations that reduce CPAP protein levels or disrupt centriole duplication, leading to microcephaly.
Gain of Function (GOF)
Not well documented; overexpression in some cancers may contribute to centrosome amplification.
Dominant Negative (DN)
Not reported for CPAP; all known disease-associated mutations are recessive.
View complete mutation data：
Gene Ontology (GO)
| • centrosome (GO:0005813) | • centriole replication (GO:0007099) |
| • centriole (GO:0005814) | • microtubule binding (GO:0008017) |
| • gamma-tubulin binding (GO:0043015) | • cell division (GO:0051301) |
Pathways
• Centrosome maturation and centriole duplication
• Cell cycle
• mitotic
Protein Summary
CPAP (CENPJ) is a 1338-amino-acid protein localized to the centrosome. It contains a G-box domain that binds gamma-tubulin and is essential for centriole elongation. CPAP interacts with other centrosomal proteins (e.g., CEP152, STIL) to regulate centriole duplication. Loss of CPAP function leads to reduced centriole number and impaired neurogenesis, causing primary microcephaly.
Related Services
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