Gremlin-1 (isoform-1) belongs to a group of diffusible proteins that bind to ligands of the TGF-beta family and regulate their activity by inhibiting their access to signaling receptors. The interplay between TGF-beta ligands and their natural antagonists has major biological significance during development processes, in which cellular response can vary considerably depending upon the local concentration of the signaling molecule. Gremlin-1 is highly expressed in the small intestine, fetal brain, and colon; and is expressed at lower levels in the brain, prostate, pancreas, and in skeletal muscle. Gremlin-1 regulates multiple functions in early development by specifically binding to, and inhibiting the function of, BMP-2, -4, and -7. It also plays a role in carcinogenesis and kidney branching morphogenesis. Recombinant Human Gremlin-1 is a 18.3 kDa protein containing 160 amino acid residues.