Free Fatty Acid Receptors

Free Fatty Acid (FFA) receptors are a group of G_q/11 protein-coupled receptors that are currently classified into FFA1, FFA2, FFA3 and FFA4 subtypes. FFA receptors are concentrated in the pancreatic islet cells (particularly FFA1) and in the brain, with lower expression levels found in adipose tissue, peripheral blood mononuclear cells, neutrophils and monocytes.

FFAs 1, 2 and 3 genes are co-located on chromosome 19 and have closely related sequences, while FFA4 is located on chromosome 10 and has little homology with the other FFAs. FFA1 and FFA4 are activated by long-chain fatty acids (FA), whereas FFA2 and FFA3 are activated by short-chain fatty acids. FFA1 is found principally in pancreatic β cells and is involved in modulation of glucose-stimulated insulin release, while the other FFA receptors are expressed in pancreatic α, β and δ cells. FFA receptors are also expressed in enteroendocrine cells in the gastrointestinal tract where activation by FFA stimulates incretin secretion. FFA2 and FFA4 are additionally expressed in adipose tissue, where they may have a role in obesity, as well as in different immune cells, being involved in regulating inflammatory processes in the gut. FFA3 has a role in modulating inflammatory processes in the airways, and is also expressed in sympathetic ganglia.

GPR84 is a structurally unrelated G protein-coupled receptor that is putatively activated by medium-chain FA and is found on immune cells, including glial cells, and in adipocytes. Studies suggest a role for GPR84 in inflammatory diseases, such as rheumatoid arthritis and inflammatory bowel disease.

External sources of pharmacological information for Free Fatty Acid Receptors :

• IUPHAR Receptor Code

• BJP Guide

Free Fatty Acid Receptor Gene Data