Recombinant Mouse RGM-B Protein, CF

RGM-B, also known as DRAGON, is a 40 kDa member of the repulsive guidance molecule (RGM) family of GPI-linked neuronal and muscle membrane proteins (1, 2). It is synthesized as a preproprotein that consists of a 48 amino acid (aa) signal sequence, a 367 aa mature region, and a 21 aa C-terminal prosegment (3). RGM-B contains two potential N-linked glycosylation sites and an abbreviated von Willebrand factor domain. Potential proteolytic cleavage within the VWF domain is supported by R&D Systems’ in house data (4). Within the region following the VWF domain, mouse RGM-B shares 49% and 43% aa sequence identity with RGM-A and RGM-C, respectively. It shares 90%, 79%, 92%, and 93% aa sequence identity with bovine, chicken, human, and macaque RGM-B, respectively. RGM-B is expressed in the developing and adult nervous system, particularly in the dorsal root ganglia and mantle layer of the spinal cord (3 - 5). In mouse, it shows a complementary, non-overlapping distribution with RGM-A (2 - 5). RGM-B is also expressed in fetal and adult enteric ganglia and in postnatal intestinal epithelium (6). RGM-B expression has been detected in neuronal cell bodies and proximal axonal segments (4) but is also present on the cell surface, where it interacts homophilically and mediates neuronal adhesion (3). RGM-B additionally functions as a BMP coreceptor. It directly binds BMP-2 and -4 but not other TGF-beta family proteins (7). RGM-B associates with BMP type I (ALK-2, -3, -6) and type II (Activin RIIA, Activin RIIB) receptors and enhances BMP signaling (7).