Dynamic roles for the N-terminus of the yeast G protein-coupled receptor Ste2p

摘要: The Saccharomyces cerevisiae α-factor receptor Ste2p has been used extensively as a model to understand the molecular mechanism of signal transduction by G protein-coupled receptors (GPCRs). Single and double cysteine mutants were created served surrogates detect intramolecular interactions dimerization using disulfide cross-linking methodology. When mutation was introduced into phylogenetically conserved tyrosine residue at position 26 (Y26C) in N-terminus Ste2p, increased greatly. amount dimer formed this Y26C mutant greatly reduced ligand binding even though site is far removed from N-terminus; lowering formation consistent with conformational change upon activation. Dimerization decreased mutations Y26C/V109C or Y26C/T114C indicating that Y26 close proximity V109 T114 extracellular loop 1 native Ste2p. Combined earlier studies, these results indicate previously unrecognized roles for perhaps GPCRs general, reveal specific region, involved GPCR signaling, intrareceptor interactions, dimerization.