CIB1
Description
The CIB1 (calcium and integrin binding 1) is a protein-coding gene located on chromosome 15.
Calcium and integrin-binding protein 1 is a protein that in humans is encoded by the CIB1 gene and is located in Chromosome 15. The protein encoded by this gene is a member of the calcium-binding protein family. The specific function of this protein has not yet been determined; however this protein is known to interact with DNA-dependent protein kinase and may play a role in kinase-phosphatase regulation of DNA end-joining. This protein also interacts with integrin alpha(IIb)beta(3), which may implicate this protein as a regulatory molecule for alpha(IIb)beta(3).
== Structure and function == CIB1 is a small protein with a molecular weight of approximately 22 kDa. It has a conserved calcium-binding EF hand domain, which consists of two alpha-helices connected by a loop. CIB1 also has an integrin-binding domain, located near the N-terminus of the protein. In addition, CIB1 has a coiled-coil domain and a C-terminal domain. CIB1 is involved in regulating cell adhesion, migration, and differentiation, as well as other cellular processes. It interacts with integrins, which are transmembrane receptors that play a key role in cell signaling and adhesion to the extracellular matrix.
CIB1, also known as Calcium- and integrin-binding protein, Calmyrin, DNA-PKcs-interacting protein, Kinase-interacting protein, SNK-interacting protein 2-28, is a calcium-binding protein that plays a key role in regulating a wide range of cellular processes. These include cell differentiation, cell division, cell proliferation, cell migration, thrombosis, angiogenesis, cardiac hypertrophy, and apoptosis. CIB1 is involved in bone marrow megakaryocyte differentiation by negatively regulating thrombopoietin-mediated signaling. It participates in the endomitotic cell cycle of megakaryocytes, a unique form of mitosis where both karyokinesis and cytokinesis are interrupted. CIB1 also plays a role in integrin signaling by negatively regulating alpha-IIb/beta3 activation in thrombin-stimulated megakaryocytes, thereby preventing platelet aggregation. Furthermore, CIB1 upregulates PTK2/FAK1 activity and is essential for the recruitment of PTK2/FAK1 to focal adhesions, suggesting its importance in focal adhesion formation. CIB1 positively regulates cell migration on fibronectin in a CDC42-dependent manner, an effect negatively regulated by PAK1. It functions as a negative regulator of stress-activated MAP kinase (MAPK) signaling pathways and downregulates inositol 1,4,5-trisphosphate receptor-dependent calcium signaling. CIB1 is involved in the translocation of sphingosine kinase SPHK1 to the plasma membrane in a N-myristoylation-dependent manner, preventing TNF-alpha-induced apoptosis. It regulates serine/threonine-protein kinase PLK3 activity for proper cell division progression. CIB1 plays a role in microtubule (MT) dynamics during neuronal development, disrupting the MT depolymerization activity of STMN2, which attenuates NGF-induced neurite outgrowth and the MT reorganization at the edge of lamellipodia. It promotes cardiomyocyte hypertrophy via activation of the calcineurin/NFAT signaling pathway, stimulating calcineurin PPP3R1 activity by mediating its anchoring to the sarcolemma. In ischemia-induced (pathological or adaptive) angiogenesis, CIB1 stimulates endothelial cell proliferation, migration, and microvessel formation by activating the PAK1 and ERK1/ERK2 signaling pathway. CIB1 also promotes cancer cell survival and proliferation. It may regulate cell cycle and differentiation of spermatogenic germ cells, and/or differentiation of supporting Sertoli cells.
CIB1 is also known as CIB, CIBP, EV3, KIP1, PRKDCIP, SIP2-28.
