About Calcium and Integrin Binding:
A CIB1 enzyme is a calcium-binding protein that is involved in the regulation of various cellular processes. While there’s far from a complete understanding of what this enzyme does, it has been shown to interact and influence various other factors. For example, it plays a role in cell differentiation, cell division, cell proliferation, cell migration, thrombosis, angiogenesis, cardiac hypertrophy, and apoptosis. We’ll take a look at some more examples below.
CIB1 can be involved in the process of bone marrow megakaryocyte differentiation. The process happens when it negatively regulates the thrombopoietin-mediated signaling pathway. It also plays a role in the endomitotic cell cycle of megakaryocyte, too. This is a type of mitosis in which both the cytokinesis and karyokinesis are interrupted. There is also a role for the CIB1 enzyme in integrin signaling; it can negatively regulate alpha-IIb/beta3 activation in thrombin-stimulated megakaryocytes preventing platelet aggregation
The CIB1 enzyme up-regulates activity related to PTK2/FAK1 activity. For the recruitment of PTK2/FAK1 to focal adhesions, it is needed, and, as such, this suggests that it is crucial for the process of focal adhesion formation. Elsewhere, it also positively regulates cell migration on fibronectin in a CDC42-dependent manner; but then this effect is negatively regulated by PAK1.
CIB1 Mechanism & Interactions
CIB1 works with MAP kinase (referred to as MAPK) signaling pathways. It has a negative regulator impact on the pathways activated by stress. It will down regulate inositol 1,4,5-trisphosphate receptor-dependent calcium signaling, and is also involved in sphingosine kinase SPHK1 translocation to the plasma membrane in a N-myristoylation-dependent manner preventing TNF-alpha-induced apoptosis. It will help to regulate serine/threonine-protein kinase PLK3 activity, which will push towards proper completion of cell division progression. It has also been shown in studies to play a role in MT -- which stands for microtubule -- dynamics during the neuronal developmental stage.
It will disrupt the MT depolymerization activity of STMN2 attenuating NGF-induced neurite outgrowth and also the MT reorganization at the edge of lamellipodia. It can also be used to promote cardiomyocyte hypertrophy via activation of the calcineurin/NFAT signaling pathway. There have been papers to suggest that it can be used to stimulate calcineurin PPP3R1 activity by mediating its anchoring to the sarcolemma. In ischemia-induced (pathological or adaptive) angiogenesis, stimulates endothelial cell proliferation, migration and microvessel formation by activating the PAK1 and ERK1/ERK2 signaling pathway. It may also promote cancer cell survival and proliferation.