KREMEN2 Full-Length MS Protein Standard (NP_078783), Labeled with [U- 13C6, 15N4]-L-Arginine and [U- 13C6, 15N2]-L-Lysine, was produced in human 293 cells (HEK293) with fully chemically defined cell culture medium to obtain incorporation efficiency at Creative-Proteomics. This gene encodes a high-affinity dickkopf homolog 1 (DKK1) transmembrane receptor. A similar protein in mouse functions interacts with with DKK1 to block wingless (WNT)/beta-catenin signaling. The encoded protein forms a ternary membrane complex with DKK1 and the WNT receptor lipoprotein receptor-related protein 6 (LRP6), and induces rapid endocytosis and removal of LRP6 from the plasma membrane. It contains extracellular kringle, WSC, and CUB domains. Alternatively spliced transcript variants encoding distinct isoforms have been observed for this gene.