CIB2: Calcium and Integrin Binding Family Member 2
A key gene in Usher syndrome and hearing loss, encoding a calcium-binding protein essential for hair cell function.
Gene Information Card
| Symbol | CIB2 |
|---|---|
| Full Name | Calcium and Integrin Binding Family Member 2 |
| Gene Type | Protein coding |
| Chromosomal Location | 15q25.1 |
| NCBI Gene ID | 10518 ncbi.nlm.nih.gov/gene/10518 |
| Ensembl ID | ENSG00000136444 |
| UniProt ID | O75838 |
| OMIM ID | 605564 |
| HGNC ID | 24579 |
| Aliases | KIP2, USH1J, DFNB48 |
Description
CIB2 (Calcium and Integrin Binding Family Member 2) encodes a calcium-binding protein that interacts with integrins and other proteins. It is essential for the function of sensory hair cells in the inner ear and photoreceptor cells in the retina. Mutations in CIB2 cause Usher syndrome type 1J (USH1J) and non-syndromic autosomal recessive hearing loss (DFNB48). The protein is involved in calcium signaling, mechanotransduction, and cell adhesion.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Usher syndrome type 1J | Loss of CIB2 function disrupts hair cell mechanotransduction and photoreceptor maintenance | OMIM #614869 |
| Non-syndromic hearing loss (DFNB48) | Impaired calcium signaling in cochlear hair cells leads to sensorineural deafness | OMIM #614869 |
| Retinitis pigmentosa (in Usher syndrome) | CIB2 deficiency causes progressive photoreceptor degeneration | OMIM #614869 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Cochlea | High | High |
| Retina | High | High |
| Brain | Moderate | Moderate |
| Heart | Low | Low |
| Kidney | Low | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HEK293 | Moderate | Commonly used for overexpression studies |
| HeLa | Low | Endogenous expression low |
| ARPE-19 (retinal pigment epithelium) | Moderate | Relevant for retinal studies |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.272G>A (p.Arg91His) | Missense | Rare | Loss of function; associated with Usher syndrome type 1J |
| c.297C>A (p.Cys99*) | Nonsense | Rare | Loss of function; causes DFNB48 |
| c.556C>T (p.Arg186Trp) | Missense | Rare | Likely loss of function; reported in hearing loss |
Mutation functional classification
Loss of Function (LOF)
Most CIB2 mutations are loss-of-function, leading to reduced protein stability or impaired calcium binding, resulting in Usher syndrome or non-syndromic hearing loss.
Gain of Function (GOF)
No gain-of-function mutations have been reported for CIB2.
Dominant Negative (DN)
No dominant-negative mutations have been described for CIB2.
View complete mutation data：
Gene Ontology (GO)
| • calcium ion binding (GO:0005509) | • integrin binding (GO:0005178) |
| • cytoplasm (GO:0005737) | • focal adhesion (GO:0005925) |
| • sensory perception of sound (GO:0007605) | • visual perception (GO:0007601) |
Pathways
• Calcium signaling pathway
• Integrin signaling pathway
• Usher syndrome (interactome)
Protein Summary
CIB2 is a 187-amino acid calcium-binding protein containing two EF-hand domains. It localizes to the cytoplasm and focal adhesions, where it modulates integrin-mediated signaling and calcium homeostasis. In the inner ear, CIB2 is critical for the development and function of hair cell stereocilia. In the retina, it supports photoreceptor survival. The protein interacts with USH1C (harmonin) and other Usher syndrome proteins.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CIB2 Knockout HEK293 Cell Line | EDJ-KQ7077 | Human | 10518 | Details Get a Quote |
| CIB2 Knockout A-549 Cell Line | EDJ-KQ31904 | Human | 10518 | Details Get a Quote |
| CIB2 Knockout HCT 116 Cell Line | EDJ-KQ31905 | Human | 10518 | Details Get a Quote |
| CIB2 Knockout HeLa Cell Line | EDJ-KQ31906 | Human | 10518 | Details Get a Quote |
