Calcium And Integrin Binding Protein 3 (CIB3)

CIB3shares a high degree of sequence similarity with DNA-dependent protein kinase catalytic subunit-interacting protein 2 in human and mouse, and like them may bind the catalytic subunit of DNA-dependent protein kinases. The exact function of this gene is not known. By database analysis, Gentry et al. (2005) identified CIB3 as a homolog of CIB1. The deduced 187-amino acid CIB3 protein shares structural features with other CIBs, including 10 helices that are separated from one another by loop regions and form 4 EF-hand motifs. All CIBs have a large insertion within EF1, suggesting that this EF-hand cannot bind Ca(2+). In addition, all CIBs have a proline that causes a kink between helices H3a and H3b, which is important for the overall structure of the hydrophobic ligand-binding pocket.