Model summary of integrins, actin, c-Abl, and apoptosis. Our data support a model in which under baseline conditions, integrin signaling supports polymerization of F-actin and F-actin maintains c-Abl in its inactive state, thus permitting survival (left). Inhibition of integrin αvβ3/αvβ5 by RGDfV or treatment with LatB both results in decreased F-actin, which then relieves the inhibition from c-Abl, allowing c-Abl to mediate apoptosis (right). Inhibition of the activated c-Abl using STI-571 (right) can inhibit the apoptosis despite the continued disruption of F-actin.