Sema3A also mediates integrin inhibition by a mechanism involving PIPKI gamma 661, a phosphatidylinositol kinase that participates in integrin mediated focal adhesion assembly. The binding of talin to beta-integrin is required for integrin activation and is strengthened by PtdIns(4,5)P(2). PIPKI gamma 661, an enzyme that makes PtdIns(4,5)P(2), is targeted to focal adhesions by an association with talin. Sema3A induced dissociation of FARP2 from Plexin-A1 stimulates an interaction between FARP2 and PIPKI gamma 661. FARP2 inhibits PIPK gamma 661's kinase activity, and thus inhibits integrin mediated adhesion.