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 an 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 (By similarity). Homodimer (Potential). Monomer. Interacts with LCP1 (By similarity). Associated with the actin cytoskeleton at membrane ruffles and at sites of phagocytosis. Cardiac allograft, spleen and testis. Expressed by inflammatory cells (macrophages and neutrophils). Expressed early and persistently in chronically rejecting cardiac allografts but is absent in cardiac syngrafts and host hearts. In the embryonic cerebellum, expression peaks at day 7. By interferon gamma. Intron retention.