抄録
Cell adhesion is a fundamental biologic process in the life of multicellular organisms. β1 integrins are heterodimeric glycoproteins, and function primarily as cell surface receptors for extracellular matrix proteins (ECM) . Interaction of cells with ECM via β1 integrins results in a change in cell behavior including mobility, growth, differentiation. This implies that β1 integrins may be capable of transmit-ting signals into the interior of cells. However, little has been known about signals generated by the binding of cells with ECM. Recently, we and others have shown that engagement of β1 integrins induced increased tyrosine phosphorylation of 105-130 kDa proteins in a number of cell types. One of these proteins was shown to be identical with pp 125FAK, a newly identified cytoplasmic protein tyrosine kinase. pp 125FAKis specifically localized at focal adhesions, and highly tyrosine phosphorylated after the ligation of integrins with their ligands or antibodies.
These findings strongly suggest that pp 125FAKacts as a signaling molecule responsible for the integrin-dependent formation of focal adhesions. pp 125FAKcan also be activated by cell transformation with p 60v-srcor by mitogenic neuropeptides including bombesin, vasopressin and endothelin. Thus, pp 125FAK may be a key regulatory molecule connecting cell adhesion, transformation, and growth. In this review, we summarize recent progress in the research of β1 integrins, especially focusing on signal transduction pathways.
