Cryo-EM structure of the rhodopsin-G?i-?? complex reveals binding of the rhodopsin C-terminal tail to the g? subunit.

ABSTRACT: One of the largest membrane protein families in eukaryotes are G protein-coupled receptors (GPCRs). GPCRs modulate cell physiology by activating diverse intracellular transducers, prominently heterotrimeric G proteins. The recent surge in structural data has expanded our understanding of GPCR-mediated signal transduction. However, many aspects, including the existence of transient interactions, remain elusive. We present the cryo-EM structure of the light-sensitive GPCR rhodopsin in complex with heterotrimeric Gi. Our density map reveals the receptor C-terminal tail bound to the G? subunit of the G protein, providing a structural foundation for the role of the C-terminal tail in GPCR signaling, and of G? as scaffold for recruiting G? subunits and G protein-receptor kinases. By comparing available complexes, we found a small set of common anchoring points that are G protein-subtype specific. Taken together, our structure and analysis provide new structural basis for the molecular events of the GPCR signaling pathway.

SUBMITTER: Tsai CJ 

PROVIDER: S-EPMC6629373 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature