Load-dependent RGD-context sensing via αV-class integrins reprograms cellular adhesion and mechanics within seconds

The cellular ability to biophysically and biochemically recognize extracellular matrix proteins is fundamental to adhesion, mechanics, migration, and morphogenesis, and influences homeostasis and disease. However, the mechanisms underlying integrin-mediated mechanosensing of the arginine-glycine-aspartic acid (RGD)-motif of vitronectin and fibronectin remain elusive. Here, we discover that within seconds of sensing vitronectin, V-class integrins initiate and strengthen adhesion biphasically through complementary mechanotransduction pathways, which rely on the catch bond behavior of single V{beta}3 integrins. The first adhesion phase requires V{beta}3 and V{beta}5 integrin-associated actomyosin and FAK activity, while V{beta}5 integrin additionally requires clathrin-mediated endocytosis. With elevating mechanical load, the second phase requires V{beta}3 integrin-directed Arp2/3, cSrc, and PI3K signaling that dominates V{beta}5 integrin in organizing the consensus adhesome on vitronectin. Simultaneously, V{beta}5 integrin regulates the mechanical stiffening of fibroblasts. Thus, V-class integrins exhibit rapid RGD-motif- and {beta}-subunit-specific programs to synergistically guide mammalian cell adhesion and mechanics upon encountering diverse extracellular environments.