CD49b/Integrin alpha-2
CD49b, the integrin alpha-2 subunit, pairs with beta-1 to form the VLA-2 receptor, historically designated platelet GPIa/IIa, which is the principal collagen receptor on platelets and fibroblasts. Beyond collagen types I through IV, α2β1 also binds laminin and several matrix metalloproteinases, supporting matrix remodeling near wounds. On T cells, CD49b has gained attention as a defining surface marker of murine type 1 regulatory T cells. Congenital ITGA2 deficiency produces a mild platelet-type bleeding disorder by impairing collagen-induced aggregation, and α2β1 expression levels, governed by common 807C/T-type polymorphisms, modulate thrombosis risk.
