Integrin alpha 2 beta 1 (VLA-2) is one of twelve Integrin family adhesion receptors that share the beta 1 subunit. It is one of six very late antigens expressed on activated T cells. Divalent cations and intracellular (inside-out) signaling convert it to its most active, extended, and open conformation. alpha 2 beta 1 binds to Collagen types I, II, and III, Laminin, Decorin, E-Cadherin, and Collectin molecules such as C1q. Platelet a2b1, also called GPIa, cooperates with GPVI to coordinate platelet collagen binding and activation. Adhesion is enhanced by crosstalk with Syndecan-1 or HGF R/c-Met and antagonized by crosstalk with Integrin a1b1. a2b1 is additionally expressed on select hematopoietic and non-hematopoietic cells.
