Publication

Article Metrics

Citations


Online attention

Structural basis of Smoothened regulation by its extracellular domains

DOI: 10.1038/nature18934 DOI Help

Authors: Eamon F. X. Byrne (Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford) , Ria Sircar (Departments of Biochemistry and Medicine, Stanford University School of Medicine) , Paul S. Miller (Departments of Biochemistry and Medicine, Stanford University School of Medicine) , George Hedger (Department of Biochemistry, University of Oxford) , Giovanni Luchetti (Departments of Biochemistry and Medicine, Stanford University School of Medicine) , Sigrid Nachtergaele (Departments of Biochemistry and Medicine, Stanford University School of Medicine) , Mark D. Tully (Diamond Light Source) , Laurel Mydock-mcgrane (Department of Developmental Biology, Washington University School of Medicine) , Douglas F. Covey (Department of Developmental Biology, Washington University School of Medicine) , Robert P. Rambo (Diamond Light Source) , Mark S. P. Sansom (Department of Biochemistry, University of Oxford) , Simon Newstead (University of Oxford) , Rajat Rohatgi (Departments of Biochemistry and Medicine, Stanford University School of Medicine) , Christian Siebold (Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nature , VOL 535 , PAGES 517 - 522

State: Published (Approved)
Published: July 2016
Diamond Proposal Number(s): 10627

Open Access Open Access

Abstract: Developmental signals of the Hedgehog (Hh) and Wnt families are transduced across the membrane by Frizzled-class G-protein-coupled receptors (GPCRs) composed of both a heptahelical transmembrane domain (TMD) and an extracellular cysteine-rich domain (CRD). How the large extracellular domains of GPCRs regulate signalling by the TMD is unknown. We present crystal structures of the Hh signal transducer and oncoprotein Smoothened, a GPCR that contains two distinct ligand-binding sites: one in its TMD and one in the CRD. The CRD is stacked atop the TMD, separated by an intervening wedge-like linker domain. Structure-guided mutations show that the interface between the CRD, linker domain and TMD stabilizes the inactive state of Smoothened. Unexpectedly, we find a cholesterol molecule bound to Smoothened in the CRD binding site. Mutations predicted to prevent cholesterol binding impair the ability of Smoothened to transmit native Hh signals. Binding of a clinically used antagonist, vismodegib, to the TMD induces a conformational change that is propagated to the CRD, resulting in loss of cholesterol from the CRD–linker domain–TMD interface. Our results clarify the structural mechanism by which the activity of a GPCR is controlled by ligand-regulated interactions between its extracellular and transmembrane domains.

Subject Areas: Biology and Bio-materials, Chemistry


Instruments: B21-High Throughput SAXS , I24-Microfocus Macromolecular Crystallography

Discipline Tags:



Technical Tags: