Recombinant Mouse Collagen XIII alpha 1 Protein, CF

Collagen XIII alpha1 is an 85 kDa - 95 kDa protein in the type 2 transmembrane collagen family (1). Mature mouse Collagen XIII alpha1 consists of a 40 amino acid (aa) cytoplasmic domain, a 19 aa transmembrane segment, and a 692 aa extracellular domain (ECD). The ECD contains three collagenous regions separated by shorter non‑collagenous regions (2, 3). Within comparable regions of the ECD, mouse Collagen XIII alpha1 shares 85% and 88% aa sequence identity with human and rat Collagen XIII alpha1, respectively. Mouse Collagen XIII alpha1 is extensively spliced, with some isoforms showing a tissue specific distribution (2, 4). Collagen XIII alpha1 is widely expressed during development and in the adult (4, 5). It localizes to intercellular adherens junctions and cell-matrix focal adhesions (6, 7). Collagen XIII  alpha1 assembles into disulfide-linked trimers, a process that is enhanced by proline hydroxylation (2, 8). Trimerization involves triple helix formation within the collagenous domains, although portions of the non‑collagenous regions can also form coiled coils (8 ‑ 10). The ECD of trimeric Collagen XIII alpha1 is an extended rod-like structure with two flexible hinges that correspond to non‑collagenous regions (11). Collagen XIII alpha1 clusters in cholesterol-rich domains on the plasma membrane (2, 12), and it can be cleaved from the cell surface or intracellularly by a furin-like protease (12). Collagen XIII alpha1 binds the extracellular matrix molecules fibronectin, heparin, integrin  alpha1, nidogen‑2, and perlecan (11, 13). The shed ECD retains its ability to bind fibronectin and can interfere with matrix formation (14).