Recombinant Mouse beta IG-H3 Protein, CF

Beta IG-H3, also known as TGFBI and RGD-CAP, is a matricellular adaptor protein that is induced in most cell types in response to TGF-beta stimulation (1 - 4). The mouse betaIG-H3 cDNA encodes a 683 amino acid (aa) precursor that includes a 23 aa signal sequence, one EMI domain, four FAS1 domains, and one RGD motif (2). Mouse betaIG-H3 shares 91% aa sequence identity with human and porcine betaIG-H3. betaIG-H3 is expressed as a 75 kDa protein with no post-translational additions (5). Following secretion, cleavages at multiple positions near the C-terminal end liberate peptides with pro-apoptotic activity (5, 6). Peptides that encompass the RGD motif contribute to the pro-apoptotic effects of TGF-beta (6). FAS1 domains contain YH motifs that are characterized by conserved Tyr and His residues (7). The YH motifs in each of the FAS1 domains enable betaIG-H3 to bind to matrix fibronectin, collagen I, collagen VI, biglycan, and decorin (3, 8 - 11), in addition to cell expressed integrins alphaV/ beta3, alphaV beta5, and alpha3 beta1 (7, 8, 12, 13). The expression of betaIG-H3 is modulated at particular developmental stages in some cell types. It is upregulated in keratinocytes and immature dendritic cells but downregulated in osteoblasts (8, 12, 14). It promotes keratinocyte differentiation but blocks osteoblast differentiation (8, 12). betaIG-H3 stimulates macrophage endocytosis and vascular endothelial cell proliferation and migration (13, 14). High glucose levels induce betaIG-H3 in renal proximal tubule cells which is predictive of diabetic nephropathy (3). Several point mutations (clustered in the fourth FAS1 domain) of betaIG-H3 are linked to different corneal dystrophies (15). betaIG-H3 is downregulated in many cancers (4, 16) and functions as a suppressor of tumorigenicity when overexpressed (2, 4, 16).