Fig. 1. Common signaling pathways initiated by ECM-ligated integrins. Integrin signaling is dependent upon the non-receptor tyrosine kinase activities of the FAK and src proteins as well as the adaptor protein functions of FAK src and Shc to initiate downstream signaling events. Common kinase signaling cascades are illustrated, but for clarity cooperativity or cross-activation between different cascades has been omitted. One caveat to the interpretation of the role of integrins in mediating survival, as discussed here, is that kinase effects are often studied through the use of constitutively active constructs. It is not clear whether this approach precisely mimics integrin-mediated signaling pathways, as shown here. Also absent are the host of cytoskeletal proteins, including -actinin, actin, vinculin, talin and paxcillin, that function as adaptors, recruiters and scaffolds on which these signaling events occur.