Actin-binding protein that enhances membrane ruffling and RAC activation. Enhances the actin-bundling activity of LCP1. Binds calcium. Plays a role in RAC signaling and in phagocytosis. May play a role in macrophage activation and function. Promotes the proliferation of vascular smooth muscle cells and of T-lymphocytes. Enhances lymphocyte migration. Plays a role in vascular inflammation. Homodimer (Potential). Monomer. Interacts with LCP1. Associated with the actin cytoskeleton at membrane ruffles and at sites of phagocytosis. Abundantly expressed in the testis, moderately in the spleen and lymph nodes and at low levels in the liver and thymus. Detected in macrophages. Phosphorylated on serine residues.