Recombinant Mouse Integrin alpha 2 beta 1 Protein, CF

Integrin alpha 2 beta 1 is one of twelve integrin family adhesion receptors that share the beta 1 subunit (1‑3). It is the non‑covalent heterodimer of 160 kDa alpha 2 (CD49b) and 130 kDa beta 1 (CD29) type I transmembrane glycoprotein subunits. It is one of six very late antigens on activated T cells, designated VLA2 (3). The alpha 2 extracellular domain (ECD) contains an I (inserted) domain which includes the ligand binding site (2, 3). The beta 1 ECD contains a vWFA domain, which participates in binding. Each subunit then has a transmembrane sequence and a short cytoplasmic tail. The dimer is folded when it is least active. Divalent cations and intracellular (inside‑out) signaling convert it to its most active, extended and open conformation (1, 2). The 1103 amino acid (aa) mouse alpha 2 extracellular domain (ECD) shares 93% aa sequence identity with rat and  80‑81% with human, canine, bovine and equine alpha 2, while the 708 aa mouse beta 1 ECD shares 98% aa identity with rat and 93-94% with human, bovine, porcine, ovine, canine and feline beta 1. The I domain‑containing beta 1 integrins ( alpha 1 beta 1, alpha 2 beta 1, alpha 10 beta 1 and alpha 11 beta 1) all bind collagens, with alpha 2 beta 1 preferring collagens I‑III (4, 5). Platelet alpha 2 beta 1, also called GPIa, cooperates with another adhesion protein, GPVI, to coordinate platelet collagen binding and activation (3, 6, 7). Other alpha 2 beta 1 ligands include laminin, decorin, E‑cadherin, and collagen‑like regions of collectin molecules such as C1q (4). Adhesion is synergized by crosstalk with syndecan‑1 or HGF R/c‑Met, and antagonized by crosstalk with integrin alpha 1 beta 1 (8‑10). In addition to expression on selected hematopoietic cells, alpha 2 beta 1 is present on a wide variety of non‑hematopoietic cells (4). Mice deficient in the alpha 2 subunit have defects in innate immune responses, wound mast cell infiltration and angiogenesis, and platelet responses to collagen (6, 11, 12). In innate immunity, alpha 2 beta 1 binding to C1q initiates the complement cascade and co‑stimulates mast cell activation, triggering neutrophil influx (4, 12).