Evidence that the Rhodopsin Kinase (GRK1) N-Terminus and the Transducin Gα C-Terminus Interact with the Same “Hydrophobic Patch” on Rhodopsin TM5

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• 作者：Amber M. Jones Brunette ; Abhinav Sinha ; Larry David ; David L. Farrens
• 刊名：Biochemistry
• 出版年：2016
• 出版时间：June 7, 2016
• 年：2016
• 卷：55
• 期：22
• 页码：3123-3135
• 全文大小：714K
• 年卷期：0
• ISSN：1520-4995

文摘

Phosphorylation of G protein-coupled receptors (GPCRs) terminates their ability to couple with and activate G proteins by increasing their affinity for arrestins. Unfortunately, detailed information regarding how GPCRs interact with the kinases responsible for their phosphorylation is still limited. Here, we purified fully functional GPCR kinase 1 (GRK1) using a rapid method and used it to gain insights into how this important kinase interacts with the GPCR rhodopsin. Specifically, we find that GRK1 uses the same site on rhodopsin as the transducin (G_t) G_tα C-terminal tail and the arrestin “finger loop”, a cleft formed in the cytoplasmic face of the receptor upon activation. Our studies also show GRK1 requires two conserved residues located in this cleft (L226 and V230) that have been shown to be required for G_t activation due to their direct interactions with hydrophobic residues on the G_α C-terminal tail. Our data and modeling studies are consistent with the idea that all three proteins (G_t, GRK1, and visual arrestin) bind, at least in part, in the same site on rhodopsin and interact with the receptor through a similar hydrophobic contact-driven mechanism.