free fatty acid receptors 2, 3, and similar proteins, member of the class A family of seven-transmembrane G protein-coupled receptors
This subgroup includes free fatty acid receptor 2 (FFAR2), FFAR3, and similar proteins. They are a member of the class A G-protein coupled receptors that bind free fatty acids. The FFAR subfamily is composed of three receptors, each encoded by a separate gene (FFAR1, FFAR2, and FFAR3). These genes and a fourth pseudogene, GPR42, are localized together on chromosome 19. FFAR2 and FFAR3 are cell-surface receptors for short chain FFAs (SCFAs) with different ligand affinities, whereas FFAR1 is a receptor for medium- and long-chain FFAs. FFAR2 activation by SCFA suppresses adipose insulin signaling, which leads to inhibition of fat accumulation in adipose tissue. FAAR3 is expressed in intestinal L cells, which produces glucagon-like peptide 1 (GLP-1) and peptide YY (PYY), thus suggesting that this receptor may be involved in energy homeostasis. FFARs are considered important components of the body's nutrient sensing mechanism, and therefore, these receptors are potential therapeutic targets for the treatment of metabolic disorders, such as type 2 diabetes and obesity.