The human genome encodes 850 G protein-coupled receptors (GPCRs), half of which are considered potential drug targets. GPCRs transduce extracellular stimuli into a plethora of vital physiological processes. Consequently, GPCRs are an attractive drug target class.
View Article and Find Full Text PDFG protein-coupled receptors (GPCRs) represent an important group of membrane proteins that play a central role in modern medicine. Unfortunately, conformational promiscuity hampers full therapeutic exploitation of GPCRs, since the largest population of the receptor will adopt a basal conformation, which subsequently challenges screens for agonist drug discovery programs. Herein, we describe a set of peptidomimetics able to mimic the ability of G proteins in stabilizing the active state of the β adrenergic receptor (β AR) and the dopamine 1 receptor (D1R).
View Article and Find Full Text PDFRic-8A is a cytosolic Guanine Nucleotide exchange Factor (GEF) that activates heterotrimeric G protein alpha subunits (Gα) and serves as an essential Gα chaperone. Mechanisms by which Ric-8A catalyzes these activities, which are stimulated by Casein Kinase II phosphorylation, are unknown. We report the structure of the nanobody-stabilized complex of nucleotide-free Gα bound to phosphorylated Ric-8A at near atomic resolution by cryo-electron microscopy and X-ray crystallography.
View Article and Find Full Text PDFNat Struct Mol Biol
December 2019
Classically, G-protein-coupled receptors (GPCRs) are thought to activate G protein from the plasma membrane and are subsequently desensitized by β-arrestin (β-arr). However, some GPCRs continue to signal through G protein from internalized compartments, mediated by a GPCR-G protein-β-arr 'megaplex'. Nevertheless, the molecular architecture of the megaplex remains unknown.
View Article and Find Full Text PDFβ-Arrestins (βarrs) interact with G protein-coupled receptors (GPCRs) to desensitize G protein signaling, to initiate signaling on their own, and to mediate receptor endocytosis. Prior structural studies have revealed two unique conformations of GPCR-βarr complexes: the "tail" conformation, with βarr primarily coupled to the phosphorylated GPCR C-terminal tail, and the "core" conformation, where, in addition to the phosphorylated C-terminal tail, βarr is further engaged with the receptor transmembrane core. However, the relationship of these distinct conformations to the various functions of βarrs is unknown.
View Article and Find Full Text PDFActa Crystallogr F Struct Biol Commun
November 2014
GPCR-G-protein complexes are one of the most important components of cell-signalling cascades. Extracellular signals are sensed by membrane-associated G-protein-coupled receptors (GPCRs) and transduced via G proteins towards intracellular effector molecules. Structural studies of these transient complexes are crucial to understand the molecular details of these interactions.
View Article and Find Full Text PDFThere is growing interest in using antibodies as auxiliary tools to crystallize proteins. Here we describe a general protocol for the generation of Nanobodies to be used as crystallization chaperones for the structural investigation of diverse conformational states of flexible (membrane) proteins and complexes thereof. Our technology has a competitive advantage over other recombinant crystallization chaperones in that we fully exploit the natural humoral response against native antigens.
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