Posttranslational modifications of endothelin receptor type B

Endothelin receptor type B (ETb) is one of the two ET receptor subtypes, both of which belong to the G protein-coupled receptor (GPCR) superfamily. The primary amino acid sequence of ETb, published in 1990, predicted potential posttranslational modifications of the receptor protein, and in the last couple of years, we and others presented direct experimental evidence for palmitoylation and phosphorylation of ETb. Functional evaluation of both substitution and deletion mutants indicated a negative role on the part of these modifications in the ligand binding capacities and cellular sequestrations of the receptors. At least one of them, palmitoylation, however, appears to be critically involved in the coupling with G proteins.