IQGAP1 as signal integrator: Ca2+, calmodulin, Cdc42 and the cytoskeleton.

A family of proteins known as IQGAPs have been identified in yeast, amebas and mammals. IQGAPs are multidomain molecules that contain several protein-interacting motifs which mediate binding to target proteins. Mammalian IQGAP1 is a component of signaling networks that are integral to maintaining cytoskeletal architecture and cell-cell adhesion. Published data suggest that IQGAP1 is a scaffolding protein that modulates cross-talk among diverse pathways in complex regulatory circuits. These pathways include modulating the actin cytoskeleton, mediating signaling by Rho family GTPases and calmodulin, regulating E-cadherin and beta-catenin function and organizing microtubules.