Ionized calcium-binding adapter molecule 1 (Iba1), also known as allograft inflammatory factor-1 (AIF-1), calcium-binding protein that is thought to play a role in macrophage activation and function. This gene is induced by cytokines and interferon. Its protein product is thought to be involved in negative regulation of growth of vascular smooth muscle cells, which contributes to the anti-inflammatory response to vessel wall trauma. Three transcript variants encoding different isoforms have been found for this gene.