Integrin alpha-9/beta-1 (ITGA9:ITGB1) is a receptor for VCAM1, cytotactin and osteopontin. It recognizes the sequence A-E-I-D-G-I-E-L in cytotactin. Heterodimer of an alpha and a beta subunit. Alpha-9 (ITGA9) associates with beta-1 (ITGB1). Integrin ITGA9:ITGB1 interacts with FBLN5 (via N-terminus). In airway epithelium, in the basal layer of squamous epithelium, and in smooth muscle, skeletal muscle, and hepatocytes. Abundantly expressed in fetal lung and lung cancers. Up-regulated in small cell lung cancers (SCLC). Belongs to the integrin alpha chain family.