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Kozielewicz P, Turku A, Schulte G. Molecular Pharmacology of Class F Receptor Activation. Mol Pharmacol 2019; 97:62-71. [PMID: 31591260 DOI: 10.1124/mol.119.117986] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 09/25/2019] [Indexed: 12/29/2022] Open
Abstract
The class Frizzled (FZD) or class F of G protein-coupled receptors consists of 10 FZD paralogues and Smoothened (SMO). FZDs coordinate wingless/Int-1 signaling and SMO mediates Hedgehog signaling. Class F receptor signaling is intrinsically important for embryonic development and its dysregulation leads to diseases, including diverse forms of tumors. With regard to the importance of class F signaling in human disease, these receptors provide an attractive target for therapeutics, exemplified by the use of SMO antagonists for the treatment of basal cell carcinoma. Here, we review recent structural insights in combination with a more detailed functional understanding of class F receptor activation, G protein coupling, conformation-based functional selectivity, and mechanistic details of activating cancer mutations, which will lay the basis for further development of class F-targeting small molecules for human therapy. SIGNIFICANCE STATEMENT: Stimulated by recent insights into the activation mechanisms of class F receptors from structural and functional analysis of Frizzled and Smoothened, we aim to summarize what we know about the molecular details of ligand binding, agonist-driven conformational changes, and class F receptor activation. A better understanding of receptor activation mechanisms will allow us to engage in structure- and mechanism-driven drug discovery with the potential to develop more isoform-selective and potentially pathway-selective drugs for human therapy.
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Affiliation(s)
- Pawel Kozielewicz
- Section of Receptor Biology and Signaling, Department Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Ainoleena Turku
- Section of Receptor Biology and Signaling, Department Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Gunnar Schulte
- Section of Receptor Biology and Signaling, Department Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Schulte G, Kozielewicz P. Structural insight into Class F receptors - What have we learnt regarding agonist-induced activation? Basic Clin Pharmacol Toxicol 2019; 126 Suppl 6:17-24. [PMID: 30925000 DOI: 10.1111/bcpt.13235] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 03/19/2019] [Indexed: 12/11/2022]
Abstract
Class F receptors, including the ten Frizzleds (FZD1-10 ) and SMO, mediate the effects of WNTs and hedgehog proteins and belong to the superfamily of G protein-coupled receptors (GPCRs). While the recent, high-resolution insight into mechanisms of GPCR activation provides a better understanding of receptor activation in Class A, B and C GPCRs, it remains unclear how Class F receptors bind their ligands, how ligand binding is translated to receptor activation and how signal initiation and specification are achieved. Here, we summarize recent efforts in elucidating Class F receptor structure and activation mechanisms and critically discuss the progress made in this area. A better understanding of the activation mechanisms of Class F receptors is required to engage in mechanism-based and structure-guided drug discovery to exploit the large therapeutic potential of targeting these receptors pharmacologically.
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Affiliation(s)
- Gunnar Schulte
- Section of Receptor Biology & Signaling, Department Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Paweł Kozielewicz
- Section of Receptor Biology & Signaling, Department Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden
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Wright SC, Kozielewicz P, Kowalski-Jahn M, Petersen J, Bowin CF, Slodkowicz G, Marti-Solano M, Rodríguez D, Hot B, Okashah N, Strakova K, Valnohova J, Babu MM, Lambert NA, Carlsson J, Schulte G. A conserved molecular switch in Class F receptors regulates receptor activation and pathway selection. Nat Commun 2019; 10:667. [PMID: 30737406 PMCID: PMC6368630 DOI: 10.1038/s41467-019-08630-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 01/22/2019] [Indexed: 12/21/2022] Open
Abstract
Class F receptors are considered valuable therapeutic targets due to their role in human disease, but structural changes accompanying receptor activation remain unexplored. Employing population and cancer genomics data, structural analyses, molecular dynamics simulations, resonance energy transfer-based approaches and mutagenesis, we identify a conserved basic amino acid in TM6 in Class F receptors that acts as a molecular switch to mediate receptor activation. Across all tested Class F receptors (FZD4,5,6,7, SMO), mutation of the molecular switch confers an increased potency of agonists by stabilizing an active conformation as assessed by engineered mini G proteins as conformational sensors. Disruption of the switch abrogates the functional interaction between FZDs and the phosphoprotein Dishevelled, supporting conformational selection as a prerequisite for functional selectivity. Our studies reveal the molecular basis of a common activation mechanism conserved in all Class F receptors, which facilitates assay development and future discovery of Class F receptor-targeting drugs. Class F receptors are therapeutic targets in human disease and understanding their structural changes during receptor activation may provide important pharmacological insight. Here, the authors combine computational and experimental methods to identify a molecular switch in TM6/7 of Class F receptors that mediates receptor activation.
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Affiliation(s)
- Shane C Wright
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Paweł Kozielewicz
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Maria Kowalski-Jahn
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Julian Petersen
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Carl-Fredrik Bowin
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Greg Slodkowicz
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, United Kingdom
| | - Maria Marti-Solano
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, United Kingdom
| | - David Rodríguez
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, P.O. Box 596, SE-751 24, Uppsala, Sweden
| | - Belma Hot
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Najeah Okashah
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, Georgia, 30912, USA
| | - Katerina Strakova
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - Jana Valnohova
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden
| | - M Madan Babu
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge, CB2 0QH, United Kingdom
| | - Nevin A Lambert
- Department of Pharmacology and Toxicology, Medical College of Georgia at Augusta University, Augusta, Georgia, 30912, USA
| | - Jens Carlsson
- Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University, P.O. Box 596, SE-751 24, Uppsala, Sweden
| | - Gunnar Schulte
- Section of Receptor Biology & Signaling, Dept. Physiology & Pharmacology, Karolinska Institutet, S17165, Stockholm, Sweden.
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