A single mutation in arrestin-2 prevents ERK1/2 activation by reducing c-Raf1 binding

摘要: Arrestins regulate the signaling and trafficking of G protein-coupled receptors (GPCRs). GPCR complexes with both nonvisual arrestins channel to protein-independent pathways, one which is activation extracellular signal regulated kinase 1/2 (ERK1/2). Here we used alanine-scanning mutagenesis residues on nonreceptor-binding surface conserved between arrestin-2 arrestin-3. We show that an Arg307Ala mutation significantly reduced binding c-Raf1, whereas mutant active phosphorylated receptor downstream kinases MEK1 ERK2 was not affected. In contrast wild-type arrestin-2, failed rescue arrestin-dependent ERK1/2 via β2-adrenergic in arrestin-2/3 double knockout mouse embryonic fibroblasts. Thus, Arg307 plays a specific role c-Raf1 indispensable productive scaffolding c-Raf1-MEK1-ERK1/2 cascade. specifically eliminates through ERK, makes arrestin-2-Arg307Ala first signaling-biased arrestin constructed. crystal structure side chain homologous arrestin-3 residue Lys308 points different direction. Alanine substitution does affect its ability promote activation, suggesting two perform same function distinct molecular mechanisms.