SRGAP3 is a 1099 amino acid protein containing 1 FCH domain, 1 Rho-GAP domain and 1 SH3 domain. Expressed highly in brain, and in lower levels in kidney, WRP is thought to play a role in cell migration through its interaction with Cdc42 and Rac1. Cdc42 and Rac1 are two intracellular signaling proteins that regulate the multistep cell migration process. WRP downregulates Cdc42 and Rac1 activity, thereby impairing actin and microtubule dynamics, the formation of protrusions, and total cell migration. Defects in the gene encoding WRP have been linked to severe idiopathic mental retardation. Three isoforms of WRP exist as a result of alternative splicing events.