Visual Overview
Abstract
The family of human G protein–coupled receptors (GPCRs) comprises about 800 different members, with about 35% of current pharmaceutical drugs targeting GPCRs. However, GPCR structural biology, necessary for structure-guided drug design, has lagged behind that of other membrane proteins, and it was not until the year 2000 when the first crystal structure of a GPCR (rhodopsin) was solved. Starting in 2007, the determination of additional GPCR structures was facilitated by protein engineering, new crystallization techniques, complexation with antibody fragments, and other strategies. More recently, the use of camelid heavy-chain-only antibody fragments (nanobodies) as crystallographic chaperones has revolutionized the field of GPCR structural biology, aiding in the determination of more than 340 GPCR structures to date. In most cases, the GPCR structures solved as complexes with nanobodies (Nbs) have revealed the binding mode of cognate or non-natural ligands; in a few cases, the same Nb has acted as an orthosteric or allosteric modulator of GPCR signaling. In this review, we summarize the multiple ingenious strategies that have been conceived and implemented in the last decade to capitalize on the discovery of nanobodies to study GPCRs from a structural perspective.
SIGNIFICANCE STATEMENT G protein–coupled receptors (GPCRs) are major pharmacological targets, and the determination of their structures at high resolution has been essential for structure-guided drug design and for insights about their functions. Single-domain antibodies (nanobodies) have greatly facilitated the structural determination of GPCRs by forming complexes directly with the receptors or indirectly through protein partners.
Footnotes
- Received June 20, 2024.
- Accepted July 24, 2024.
This work was supported in part by grants from National Institutes of Health National Eye Institute [Grant R01EY009339] (to K.P.), [Grant R01EY0034519] (to K.P.), and [Grant P30EY034070] (core grant to Department of Ophthalmology, Gavin Herbert Eye Institute at the University of California, Irvine) (UCI). The authors acknowledge support to the Department of Ophthalmology, Gavin Herbert Eye Institute at UCI from an unrestricted Research to Prevent Blindness Award. The authors also acknowledge the Institute for Rapid Antibody Engineering and Evolution, part of the Engineering + Health Initiative of the UCI Samueli School of Engineering, for additional support.
The authors have declared a conflict of interest. C.C.L. is a cofounder of K2 Biotechnologies, Inc., which uses OrthoRep for protein engineering. K.P. is a consultant for Polgenix, Inc. and serves on the Scientific Advisory Board at Hyperion Eye Ltd.
↵
This article has supplemental material available at molpharm.aspetjournals.org.
- Copyright © 2024 by The American Society for Pharmacology and Experimental Therapeutics
MolPharm articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|
