Role ofβ1 integrin cytoplasmic domain in signaling and cell adhesion

摘要: We have investigated the intracellular signaling events generated during interaction of integrins with extracellular matrix proteins in human endothelial cells (HEC). Within 30 s from adhesion to fibronectin, HEC showed increased tyrosine phosphorylation a group molecular mass 100–130 and 70 kDa. Tyrosine these was triggered by several ligands, including collagens type I IV, laminin vitronectin could be mimicked antibodies toα3βl,α5βl, andα6β1 integrin complexes. Among phosphoproteins regulated integrins, we identified focal kinase pl25FAK. Inhibition genistein fibronectin severly prevented organization adhesions actin stress fibers, but did not inhibit adhesionper se. The role ofβi stimulating further analyzing naturally occurring variant ofβ1 integrin(β1B) distinct cytoplasmic domain (Altruda et al., 1990).Β1B, expressed Chinese hamster ovary (CHO) cells, formed heterodimers theα3 andα5 subunits bind RGD-dependent manner (Balzac 1993). Theα5β1B complex, however, stimulate 100-130 kDa localize at adhesions. Moreover, expressingβ1B reduced migration Boyden chamber assay poor spreading on laminin. This generalized adhesive defect since cell vitronectin, aβ3 integrin-dependent adhesion, unchanged. These data show thatβ1 is critical stimulation protein phosphorylation; this signalling, moreover, important fibers control proteins.