AIF1, also known as IBA1, is an actin-binding protein. AIF1 is expressed selectively in human macrophage-like cell lines, and in a subset of CD68(+) macrophages in the interstitial and perivascular spaces of human heart allografts. It is expressed in macrophages and neutrophils. AIF1 enhances membrane ruffling and RAC activation. AIF1 enhances the actin-bundling activity of LCP1. It also enhances lymphocyte migration. AIF1 may play a role in macrophage activation and function. It binds calcium and plays a role in RAC signaling and in phagocytosis. It promotes the proliferation of vascular smooth muscle cells and of T-lymphocytes.
