CD49c/Integrin alpha-3
CD49c, the integrin alpha-3 subunit, pairs almost exclusively with beta-1 to create α3β1, the major laminin receptor of epithelial basement membranes, which additionally engages epiligrin/kalinin, nidogen and fibronectin. The integrin localizes to cell-cell and cell-matrix contacts in keratinocytes and renal, pulmonary and intestinal epithelium, where it organizes adhesion and directs matrix metalloproteinase trafficking for tissue remodeling. Human ITGA3 mutations cause the ILNEB syndrome, combining interstitial lung disease with nephrotic syndrome and epidermal blistering, illustrating the molecule's nonredundant role at epithelial interfaces. In tumors, α3β1 supports squamous carcinoma migration and matrix deposition.
