Regulation of proliferation and apoptosis by integrin engagement in ALL cells as detected by microarrays and validation experiments.

Our model depicts the regulation of proteins involved in the control of apoptosis as well as the induction of proteins involved in proliferation or cytoskeletal rearrangements. Under apoptotic conditions, β1 integrin ligation represses the induction and activation of caspase 3 and 7, the induction of Requiem and of the AP-1 complex composed of c-Fos and JunD. On the other hand, integrin engagement leads to increased expression of survivin and XIAP. It also enhances the expression of FBI-1 that may inhibit further production of components from the extracellular matrix. Integrin ligation also increases the expression of CCT4 that assists the folding of both actin and tubulin. Finally, FRAP and CCT4 have been shown to play a role in proliferation. ECM indicates extracellular matrix proteins; and †, cell death.