The G protein-coupled bile acid receptor 1 (GPBAR1) also known G-protein coupled receptor 19 (GPCR19), membrane-type receptor for bile acids (M-BAR) or TGR5 as is a protein that in humans is encoded by the GPBAR1gene.
This gene encodes a member of the G protein-coupled receptor (GPCR) superfamily. This protein functions as a cell surface receptor for bile acids. Treatment of cells expressing this GPCR with bile acids induces the production of intracellular cAMP, activation of a MAP kinase signaling pathway, and internalization of the receptor. The receptor is implicated in the suppression of macrophage functions and regulation of energy homeostasis by bile acids.
^Kawamata Y, Fujii R, Hosoya M, Harada M, Yoshida H, Miwa M, Fukusumi S, Habata Y, Itoh T, Shintani Y, Hinuma S, Fujisawa Y, Fujino M (2003). "A G protein-coupled receptor responsive to bile acids". J. Biol. Chem.278 (11): 9435–40. doi:10.1074/jbc.M209706200. PMID12524422.
Watanabe M, Houten SM, Mataki C, et al. (2006). "Bile acids induce energy expenditure by promoting intracellular thyroid hormone activation.". Nature439 (7075): 484–9. doi:10.1038/nature04330. PMID16400329.
Thomas SM, Bhola NE, Zhang Q, et al. (2007). "Cross-talk between G protein-coupled receptor and epidermal growth factor receptor signaling pathways contributes to growth and invasion of head and neck squamous cell carcinoma.". Cancer Res.66 (24): 11831–9. doi:10.1158/0008-5472.CAN-06-2876. PMID17178880.
Yasuda H, Hirata S, Inoue K, et al. (2007). "Involvement of membrane-type bile acid receptor M-BAR/TGR5 in bile acid-induced activation of epidermal growth factor receptor and mitogen-activated protein kinases in gastric carcinoma cells.". Biochem. Biophys. Res. Commun.354 (1): 154–9. doi:10.1016/j.bbrc.2006.12.168. PMID17214962.
Keitel V, Reinehr R, Gatsios P, et al. (2007). "The G-protein coupled bile salt receptor TGR5 is expressed in liver sinusoidal endothelial cells.". Hepatology45 (3): 695–704. doi:10.1002/hep.21458. PMID17326144.