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Structure of the rhodopsin–rhodopsin kinase complex defines the rules of engagement between G protein‐coupled receptors (GPCRs) and GPCR kinases
Author(s) -
Chen Qiuyan,
Plasencia Manolo,
Li Zhuang,
Mukherjee Somnath,
Patra Dhableswar,
Chen ChunLiang,
Klose Thomas,
Yao XinQiu,
Kossiakoff Anthony,
Chang Leifu,
Andrews Philip,
Tesmer John
Publication year - 2021
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2021.35.s1.03635
Subject(s) - g protein coupled receptor kinase , rhodopsin , g protein coupled receptor , arrestin , microbiology and biotechnology , protein kinase domain , kinase , regulator of g protein signaling , transducin , biology , chemistry , g protein , biochemistry , signal transduction , gtpase activating protein , retinal , gene , mutant
G protein‐coupled receptor (GPCR) kinases (GRKs) selectively phosphorylate GPCRs in their activated states, priming them for arrestin binding and internalization. How GRKs recognize these receptors and how receptors turn on the kinase activity of GRKs is debated. Here we trapped a light activated rhodopsin (Rho*) in complex with rhodopsin kinase (GRK1) using a novel crosslinker and determined a 4.0 Å cryo‐EM structure of this complex with the aid of a GRK1‐binding Fab. GRK1‐bound Rho* adopts unique active conformations, distinct from arrestin‐1‐bound or transducin‐bound Rho*. GRK1 interacts with Rho* entirely via its N‐terminal helix and kinase small lobe, and the kinase domain overall assumes a closed, active conformation. The regulator of G protein signaling homology domain is detached from the kinase domain and is not visible in this complex. The most prominent interaction is the docking of the GRK1 N‐terminus into the cytoplasmic cleft that forms upon activation of rhodopsin. Crosslinking and functional studies validate GRK specific interactions in the structure and reveal dynamics consistent with the ability of GRK1 to phosphorylate multiple sites in the C‐terminus of Rho*. We also identify residues required for the activation of GRK1 by acidic phospholipids that would reside adjacent to the visible receptor–GRK interface. Our data provides not only a model for how GRKs engage and are synergistically activated by receptors and anionic phospholipids, but also a potential mechanism for how arrestin biased siganling could occur in some GPCRs.