9.A.14.13.30
Free fatty acid receptor-1, FFAR1 or GPR40, of 300 aas and 7 TMSs. G-protein coupled receptor for medium and long chain saturated and unsaturated fatty acids that plays an important role in glucose homeostasis (Briscoe et al. 2003). Fatty acid binding increases glucose-stimulated insulin secretion, and may also enhance the secretion of glucagon-like peptide 1 (GLP-1) (Suckow et al. 2014). May also play a role in bone homeostasis; receptor signaling activates pathways that inhibit osteoclast differentiation (Philippe et al. 2016). Ligand binding leads to a conformation change that triggers signaling via G-proteins that activate phospholipase C, leading to an increase of the intracellular calcium concentration (Li et al. 2020). The receptor is strongly activated by gamma-linolenic acid, while myristate gives a lower response. It is also activated by phytanic acid and pristanic acid (Kruska and Reiser 2011).