Cell adhesion to extracellular matrix (ECM) components has been reported to be mediated by the integrins. These proteins link the ECM to the intracellular cytoskeletal network and to multiple intracellular signaling pathways whose activation is important for cell survival, growth, and differentiation. Integrins contain noncovalently associated α and β subunits that consist of a large extracellular region (the ligand binding domain), a short transmembrane region, and a cytoplasmic domain of varying length. In mammals, at least 17 α and 8 β subunits have been identified and these proteins can heterodimerize to form 22 different receptors. Some integrins interact with only one specific ligand. It is more common that a specific integrin recognizes multiple ligands. There is a high degree of redundancy, so that integrins which interact identically with a particular ligand do not necessarily induce the same cellular response. Either one or both subunits directly interact with a number of proximal intracellular signaling components such as cytoskeletal proteins (talin, fibronectin, α-actinin), adaptor molecules (paxillin, RACK1, p130Cas), Ca2+ binding proteins (CIB and calreticulin), and protein kinases (FAK and ILK). Such interactions initiate multiple pathways that signal in the traditional "outside-in" signaling process. When bound by ligand, they may form signaling connections with intracellular components or may remain detached from the cytoskeleton and signaling pathways. In the absence of intracellular signaling, integrin ligation can promote the assembly and organization of the intercellular ECM.
These antibodies are routinely tested by western blot analysis. Other applications were tested at BD Biosciences Pharmingen during antibody development only or reported in the literature.
