Recombinant Mouse Lgr6 Fc Chimera Protein, CF

Lgr6 (leucine‑rich repeat G‑protein-coupled receptor 6) is a seven‑transmembrane glycoprotein receptor in the Lgr family of cell surface receptors (1). While this family includes receptors for hormones such as LH, FSH, TSH, and HCG, the subfamily comprising Lgr4, Lgr5, and Lgr6 are G‑protein‑independent mediators of the potentiating effect of R‑Spondins on Wnt signaling (1‑3). Each has been identified as a marker for specific types of stem cells in tissues that are subject to constant self‑renewal such as skin, gastrointestinal tract and lungs. Mouse Lgr6 cDNA encodes 967 amino acids (aa), including a signal sequence (aa 1‑22), a long N‑terminal extracellular domain (ECD) with 15‑16 LRR domains that mediate ligand interaction (aa 25‑567), a seven‑transmembrane region (aa 568‑830), and a C‑terminal cytoplasmic region (aa 831‑967) (1). The N‑terminal ECD of mouse Lgr6 shares 92%, 97%, 91%, 88%, 83% and 77% aa sequence identity with human, rat, canine, feline, porcine and bovine Lgr6, respectively, and 55‑65% aa identity with mouse Lgr4 and Lgr5. Lgr6 expression is detected in rare cells of the brain, mammary gland, lung and skin, and is expressed on stem cells above the hair follicle bulge in the skin (2). Lgr6⁺ stem cells can produce sebaceous gland or interfollicular epidermis as well as hair follicles in vivo, during prenatal and postnatal differentiation and wound healing (2). In vitro, they can produce multiple mesenchymal lineages or neurons (4). Like Lgr4 and Lgr5, Lgr6 can bind and respond to R‑Spondins, and can enhance Wnt/ beta‑catenin signaling through increasing phosphorylation of LRP Wnt co‑receptors (3, 5). Lgr6 is often up‑regulated in human gastric cancers as compared to the surrounding tissues (6).