Atomic Structure of GRK5 Reveals Distinct Structural Features Novel for G Protein-coupled Receptor Kinases.
G protein-coupled receptor kinases (GRKs) are members of the protein kinase A, G, and C families (AGC) and play a central role in mediating G protein-coupled receptor phosphorylation and desensitization. One member of the family, GRK5, has been implicated in several human pathologies, including heart failure, hypertension, cancer, diabetes, and Alzheimer disease. To gain mechanistic insight into GRK5 function, we determined a crystal structure of full-length human GRK5 at 1.8 Å resolution. GRK5 in complex with the ATP analog 5'-adenylyl β,γ-imidodiphosphate or the nucleoside sangivamycin crystallized as a monomer. The C-terminal tail (C-tail) of AGC kinase domains is a highly conserved feature that is divided into three segments as follows: the C-lobe tether, the active-site tether (AST), and the N-lobe tether (NLT). This domain is fully resolved in GRK5 and reveals novel interactions with the nucleotide and N-lobe. Similar to other AGC kinases, the GRK5 AST is an integral part of the nucleotide-binding pocket, a feature not observed in other GRKs. The AST also mediates contact between the kinase N- and C-lobes facilitating closure of the kinase domain. The GRK5 NLT is largely displaced from its previously observed position in other GRKs. Moreover, although the autophosphorylation sites in the NLT are >20 Å away from the catalytic cleft, they are capable of rapid cis-autophosphorylation suggesting high mobility of this region. In summary, we provide a snapshot of GRK5 in a partially closed state, where structural elements of the kinase domain C-tail are aligned to form novel interactions to the nucleotide and N-lobe not previously observed in other GRKs.
['Komolov|Konstantin E|KE|', 'Bhardwaj|Anshul|A|', 'Benovic|Jeffrey L|JL|']
D000266:Adenylyl Imidodiphosphate D000818:Animals D000903:Antibiotics, Antineoplastic D016367:Baculoviridae D020134:Catalytic Domain D018360:Crystallography, X-Ray D054774:G-Protein-Coupled Receptor Kinase 5 D015870:Gene Expression D006801:Humans D008958:Models, Molecular D008969:Molecular Sequence Data D009154:Mutation D010766:Phosphorylation D054730:Protein Interaction Domains and Motifs D017433:Protein Structure, Secondary D011741:Pyrimidine Nucleosides D011994:Recombinant Proteins D016415:Sequence Alignment D018411:Spodoptera
G protein-coupled receptor kinase protein kinase phosphorylation G protein-coupled receptor (GPCR) crystallography receptor regulation signal transduction