IQ Motif Containing GTPase Activating Protein 3 (IQGAP3)

Rac1 and Cdc42, members of the Rho family GTPases, control diverse cellular processes such as cell migration and morphogenesis through their effectors. IQGAP3, as a novel member of the IQGAP family, which is highly expressed in brain. IQGAP3, an effector of Rac1 and Cdc42, associates directly with actin filaments and accumulates asymmetrically at the distal region of axons in hippocampal neurons. The depletion of IQGAP3 impairs neurite or axon outgrowth in neuronal cells with the disorganized cytoskeleton, but depletion of IQGAP1 does not. Furthermore, IQGAP3 is indispensable for Rac1/Cdc42-promoted neurite outgrowth in PC12 cells. Taken together, these results indicate that IQGAP3 can link the activation of Rac1 and Cdc42 with the cytoskeletal architectures during neuronal morphogenesis.