biostudies-literatureSingh PNEI NIH HHSNHLBI NIH HHSNCI NIH HHSNIGMS NIH HHS14053-62https://www.ebi.ac.uk/biostudies/studies/S-EPMC2376226biostudies-literatureUnknown283(20)G protein-coupled receptor (GPCR) kinases (GRKs) phosphorylate activated heptahelical receptors, leading to their uncoupling from G proteins. Here we report six crystal structures of rhodopsin kinase (GRK1), revealing not only three distinct nucleotide-binding states of a GRK but also two key structural elements believed to be involved in the recognition of activated GPCRs. The first is the C-terminal extension of the kinase domain, which was observed in all nucleotide-bound GRK1 structures. The second is residues 5-30 of the N terminus, observed in one of the GRK1.(Mg2+)2.ATP structures. The N terminus was also clearly phosphorylated, leading to the identification of two novel phosphorylation sites by mass spectral analysis. Co-localization of the N terminus and the C-terminal extension nThe Journal of biological chemistryStructures of rhodopsin kinase in different ligand states reveal key elements involved in G protein-coupled receptor kinase activation.PMC2376226Y1-GM-1104EY 08061P30 EY011373P30-EY11373R01 EY008061HL071818Y1-CO-1020Palczewski KTesmer JJWang BMaeda TSingh PfalseStructures of rhodopsin kinase in different ligand states reveal key elements involved in G protein-coupled receptor kinase activation.G protein-coupled receptor (GPCR) kinases (GRKs) phosphorylate activated heptahelical receptors, leading to their uncoupling from G proteins. Here we report six crystal structures of rhodopsin kinase (GRK1), revealing not only three distinct nucleotide-binding states of a GRK but also two key structural elements believed to be involved in the recognition of activated GPCRs. The first is the C-terminal extension of the kinase domain, which was observed in all nucleotide-bound GRK1 structures. The second is residues 5-30 of the N terminus, observed in one of the GRK1.(Mg2+)2.ATP structures. The N terminus was also clearly phosphorylated, leading to the identification of two novel phosphorylation sites by mass spectral analysis. Co-localization of the N terminus and the C-terminal extension n2008-01-01T00:00:00Z2008 May2026-05-03T20:12:34.405Z2019-03-27T02:45:04ZS-EPMC23762261833961910.1074/jbc.m70897420010.1074/jbc.M708974200