GPR132

G protein coupled receptor 132, also termed G2A, is classified as a member of the proton sensing G protein coupled receptor (GPR) subfamily. Like other members of this subfamily, i.e. GPR4, OGR1 (GPR68), and TDAG8 (GPR65), G2A is a G protein coupled receptor that resides in the cell surface membrane, senses changes in extracellular pH, and can alter cellular function as a consequence of these changes. Subsequently, G2A was suggested to be a receptor for lysophosphatidylcholine (LPC). However, the roles of G2A as a pH-sensor or LPC receptor are disputed. Rather, current studies suggest that it is a receptor for certain metabolites of the polyunsaturated fatty acid, linoleic acid.

The G2A gene

G2A in humans is encoded by the GPR132 gene. The G2A gene (Gene ID: 29933) is located on chromosome 14q32.3 codes for two alternative splice variants, the original one, G2A-a, and G2A-b, that consist of 380 and 371 amino acids, respectively; the two receptor variants, when expressed in Chinese hamster ovary cells, gave very similar results when analyzed for functionality. G2A-a and G2A-b mRNA are expressed at similar levels in blood leukocytes ( macrophages, dendritic cells, neutrophils [PMN], mast cells, T lymphocytes and B lymphocytes at the highest levels followed by lower levels in spleen, lung and heart tissues; both variants are expressed at similar levels, and are almost equally induced by DNA synthesis inhibitors (hydroxyurea and cytosine arabinoside) or a differentiation inducer (all-trans retinoic acid) in HL-60 human leukemic cells.