Fig. 2. The hierarchy of integrin-specific signals. Integrin 
vß3
selectively associates with and enhances signaling by RTK receptors. It also
activates several pathways including NF-
B, calcium influx and possibly
others yet to be identified. Integrins vß3, 5ß1 and
1 ß1 interact with caveolin and stimulate Shc phosphorylation and
possibly other events. Integrins vß3 and 5ß1 also
activate PI3K. Integrin 2ß1 stimulates p38 MAP kinase, which may
inhibit cyclin D1 expression in some cells. Most integrins activate FAK and
Rho family GTPases on rigid ECMs that resist tension and promote focal
adhesion formation. The model is meant to emphasize general trends rather than
the absolute specificity of each effect.
