Identification of intrinsically disordered regions in Angiotensin II receptor AT2R and their correlation with functionality

The Angiotensin II type 2 receptor (AT2R) is G‐protein coupled receptor that is not crystallized. A member of the anti‐inflammatory/vasodialative branch of renin‐angiotensin system (RAS), AT2R‐activation ameliorates cardiovascular diseases, strokes, and attenuates cancers. Developing functional AT2R mimetics is highly relevant to drug development. Emerging evidence suggests that Intrinsically Disordered (ID) regions in proteins facilitate their interaction with multiple protein partners. We hypothesized that loss of function mutations in the AT2R will also disrupt the ID regions of the protein. We employed three in silico ID predictors (PONDR® VLXT, DisEMBLTM and PONDR‐FIT) to identify evolutionarily conserved ID regions of the AT2R. Three conserved ID regions were predicted by these ID predictors that were located at the N‐terminus, 3rd intracellular loop (ICL) and C‐terminal cytoplasmic domain (CCD). This ID‐signature of the AT2R is altered in signaling‐deficient rat and human AT2R mutants. Mutations in the AT2R that do not alter the ID‐signature, do not affect AT2R‐signaling meditated specifically via 3rd ICL and CCD. These observations support the idea that ID‐signature can be unique to a peptide and relates to its functional property and will differ in loss of function mutations. It is conceivable the ID‐signature may serve as a guide for generating AT2R‐mimetic peptides.