Recombinant Human CRIM1 Protein, CF

Cysteine rich motor neuron 1 (CRIM1) is a type I transmembrane glycoprotein of the chordin-like cysteine-rich repeat (CRR) family of BMP inhibitors (1 - 4). The ~130 kDa, 1036 amino acid (aa) CRIM1 contains a 34 aa signal sequence, a 905 aa extracellular domain (ECD), a 21 aa transmembrane domain and a 76 aa cytoplasmic domain. The ECD includes an N-terminal IGF-binding protein-like motif and six chordin-like von Willebrand C-type CRRs. The ECD can be released from the cell, presumably by proteolytic processing (4). Human CRIM1 ECD shows 88%, 88%, 91%, 86%, 87%, 83% and 72% aa identity with mouse, rat, dog, cow, opossum, chick and zebrafish CRIM1 ECD, respectively. CRIM1 can interact with TGF-beta family ligands, including BMPs 2, 4 and 7, via its CRR domains (4). It binds BMPs intracellularly and antagonizes them by lowering their expression, processing and secretion (4). CRIM1 is expressed in the developing spinal cord in the floor plate and developing motor neurons (1). It is also expressed by perivascular smooth muscle cells and aligns at points of cell-cell contact during endothelial cell capillary formation (2). Endothelial cell expression in vitro appears to be specific to cells that are adherent and growing (2). CRIM1 is also expressed in a spatially and temporally restricted manner in the developing lens, limbs, kidney, teeth and testis (5). Studies where CRIM1 expression is manipulated in developing mouse, chick and zebrafish support its involvement in regulation of vascular and somitic development and organogenesis (5 - 7).