pH sensing receptors pH sensing receptors:H+ GPR4, GPR65, GPR132 and OGR1 are pH sensing receptors Authored: Jupe, S, 2009-10-23 Edited: Jupe, S, 2010-03-01 Pubmed12955148 Pubmed15280385 Pubmed15326175 Pubmed17118800 Pubmed17462861 Reactome Database ID Release 43444731 Reactome, http://www.reactome.org ReactomeREACT_21323 Reviewed: D'Eustachio, P, 2009-12-11 The subfamily of G protein-coupled receptors comprising GPR4, OGR1, TDAG8, and G2A was originally characterized as a group of proteins mediating biological responses to the lipid messengers sphingosylphosphorylcholine (SPC), lysophosphatidylcholine (LPC), and psychosine. This was later replaced by reports that OGR1 and GPR4 sense acidic pH. GPR4, OGR1, and TDAG8 are now considered as proton-sensing receptors.