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608 a.a.
Key reference
DOI no: 10.1021/bi050119q Biochemistry 44:6958-6970 (2005) PubMed id: 15865441
The role of G beta gamma and domain interfaces in the activation of G protein-coupled receptor kinase 2. D.T.Lodowski, J.F.Barnhill, R.M.Pyskadlo, R.Ghirlando, R.Sterne-Marr, J.J.Tesmer. ABSTRACT
In response to extracellular signals, G protein-coupled receptors (GPCRs) catalyze guanine nucleotide exchange on Galpha subunits, enabling both activated Galpha and Gbetagamma subunits to target downstream effector enzymes. One target of Gbetagamma is G protein-coupled receptor kinase 2 (GRK2), an enzyme that initiates homologous desensitization by phosphorylating activated GPCRs. GRK2 consists of three distinct domains: an RGS homology (RH) domain, a protein kinase domain, and a pleckstrin homology (PH) domain, through which it binds Gbetagamma. The crystal structure of the GRK2-Gbetagamma complex revealed that the domains of GRK2 are intimately associated and left open the possibility for allosteric regulation by Gbetagamma. In this paper, we report the 4.5 A structure of GRK2, which shows that the binding of Gbetagamma does not induce large domain rearrangements in GRK2, although small rotations of the RH and PH domains relative to the kinase domain are evident. Mutation of residues within the larger domain interfaces of GRK2 generally leads to diminished expression and activity, suggesting that these interfaces are important for stability and remain intact upon activation of GRK2. Geranylgeranylated Gbetagamma, but not a soluble mutant of Gbetagamma, protects GRK2 from clostripain digestion at a site within its kinase domain that is 80 A away from the Gbetagamma binding site. Equilibrium ultracentrifugation experiments indicate that neither abnormally large detergent micelles nor protein oligomerization can account for the observed protection. The Gbetagamma-mediated binding of GRK2 to CHAPS micelles or lipid bilayers therefore appears to rigidify the kinase domain, perhaps by encouraging stable contacts between the RH and kinase domains.
Literature references that cite this PDB file's key reference
PubMed id Reference
19364770 C.C.Huang, K.Yoshino-Koh, and J.J.Tesmer (2009).
A Surface of the Kinase Domain Critical for the Allosteric Activation of G Protein-coupled Receptor Kinases.J Biol Chem, 284, 17206-17215.
18339619 P.Singh, B.Wang, T.Maeda, K.Palczewski, and J.J.Tesmer (2008).
Structures of rhodopsin kinase in different ligand states reveal key elements involved in G protein-coupled receptor kinase activation.J Biol Chem, 283, 14053-14062.
PDB codes: 3c4w 3c4x 3c4y 3c4z 3c50 3c51
16613860 D.T.Lodowski, V.M.Tesmer, J.L.Benovic, and J.J.Tesmer (2006).
The structure of G protein-coupled receptor kinase (GRK)-6 defines a second lineage of GRKs.J Biol Chem, 281, 16785-16793.
PDB code: 2acx The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time. Where a reference describes a PDB structure, the PDB codes are shown on the right.
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