1
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Zhao R, Liu M, Dai E, Chen C, Lv L, Peng L, He Y, Li S, Yang M. Deciphering a crucial dimeric interface governing Norrin dimerization and the pathogenesis of familial exudative vitreoretinopathy. FASEB J 2024; 38:e23493. [PMID: 38363575 DOI: 10.1096/fj.202302387r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/18/2024] [Accepted: 02/02/2024] [Indexed: 02/17/2024]
Abstract
Familial exudative vitreoretinopathy (FEVR) is a hereditary eye disease that could cause blindness. It has been established that Norrin forms dimers to activate β-catenin signaling, yet the core interface for Norrin dimerization and the precise mechanism by which Norrin dimerization contributes to the pathogenesis of FEVR remain elusive. Here, we report an NDP variant, c.265T>C (p.Phe89Leu), that interrupted β-catenin signaling by disrupting Norrin dimerization. Structural and functional analysis revealed that the Phe-89 of one Norrin monomer interacts with Pro-98, Ser-101, Arg-121, and Ile-123 of another, forming two core symmetrical dimerization interfaces that are pivotal for the formation of a "hand-by-arm" dimer. Intriguingly, we proved that one of the two core symmetrical interfaces is sufficient for dimerization and activation of β-catenin signaling, with a substantial contribution from the Phe-89/Pro-98 interaction. Further functional analysis revealed that the disruption of both dimeric interfaces eliminates potential binding sites for LRP5, which could be partially restored by over-expression of TSPAN12. In conclusion, our findings unveil a core dimerization interface that regulates Norrin/LRP5 interaction, highlighting the essential role of Norrin dimerization on β-catenin signaling and providing potential therapeutic avenues for the treatment of FEVR.
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Affiliation(s)
- Rulian Zhao
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Min Liu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Erkuan Dai
- Department of Ophthalmology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Chen
- Center for Natural Products Research, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| | - Liting Lv
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Li Peng
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Yunqi He
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Shujin Li
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Mu Yang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
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2
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Wai YZ, Chong YY, Lim LT, Hamzah N, Rahmat J. Familial exudative vitreoretinopathy in a 4 generations family of South-East Asian Descendent with FZD4 mutation (c.1501_1502del). Int J Retina Vitreous 2022; 8:30. [PMID: 35578317 PMCID: PMC9112478 DOI: 10.1186/s40942-022-00384-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 05/04/2022] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Familial Exudative Vitreoretinopathy (FEVR) is a hereditary disorder characterized by peripheral avascular retina with neovascularization. Although FEVR has been thoroughly described in multiple literature publications from different countries, there are currently limited articles describing the phenotypes of FEVR among South-East Asian Descendent. This paper describes the clinical phenotype of the FZD4 gene with c.1501_1502 deletion in a 4-generation case series of a South East Asian family. METHODS We reviewed a 4-generation case series of a South-East Asian descendent family consisting of 27 family members with 10 members diagnosed with FEVR. We observed the clinical phenotype of these series of patients, including some of the family members who underwent whole-exome sequencing, PCR amplification and DNA sequencing techniques to identify the mutated gene. RESULTS Frameshift mutation (c.1501_1502del) were found in FZD4 gene in this series of patients with the age ranging from 1 month old to 69 years old. There was a 100% (4/4) of our paediatric patients being diagnosed within 21 days of life. It was also found that 75% of patients (6/8) less than 40 years old exhibited disease asymmetry of 2 stages or more and 80% (8/10) had a history of vitreoretinal surgery or diode laser photocoagulation, with a further 50% of the adult patients identified as legally blind; the mean age of blindness was 18-years-old. CONCLUSIONS Phenotypic manifestation of FZD4 gene with c.1501_1502del mutation can be identified within the neonatal period. They have relatively greater clinical asymmetry of 2 stages or more compared to other mutations. Without treatment, most of them will have bilateral severe visual impairment around the adolescent age group.
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Affiliation(s)
- Yong Zheng Wai
- Ophthalmology Department, Hospital Kuala Lumpur, Kuala Lumpur, Malaysia.
| | | | - Lik Thai Lim
- Ophthalmology Department, Faculty of Medicine and Health Sciences, Universiti Malaysia Sarawak (UNIMAS), Kota Samarahan, Malaysia
| | - Norhafizah Hamzah
- Paediatric Ophthalmology Department, Hospital Tunku Azizah, Kuala Lumpur, Malaysia
| | - Jamalia Rahmat
- Ophthalmology Department, Hospital Kuala Lumpur, Kuala Lumpur, Malaysia
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3
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Frizzled 7 Activates β-Catenin-Dependent and β-Catenin-Independent Wnt Signalling Pathways During Developmental Morphogenesis: Implications for Therapeutic Targeting in Colorectal Cancer. Handb Exp Pharmacol 2021. [PMID: 34455486 DOI: 10.1007/164_2021_524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2024]
Abstract
Frizzled7 activates β-catenin-dependent and β-catenin-independent Wnt signalling pathways, is highly conserved through evolution from the ancient phylum hydra to man, plays essential roles in stem cells, tissue homeostasis and regeneration in the adult, and is upregulated in diverse cancers. Much of what is known about the core components of the Wnt signalling pathways was derived from studying the function of Frizzled7 orthologues in the development of lower organism. As we interrogate Frizzled7 signalling and function for therapeutic targeting in cancer, it is timely to revisit lower organisms to gain insight into the context dependent and dynamic nature of Wnt signalling for effective drug design.
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4
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Sonavane PR, Willert K. Controlling Wnt Signaling Specificity and Implications for Targeting WNTs Pharmacologically. Handb Exp Pharmacol 2021; 269:3-28. [PMID: 34463853 DOI: 10.1007/164_2021_529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Wnt signaling is critical for proper development of the embryo and for tissue homeostasis in the adult. Activation of this signaling cascade is initiated by binding of the secreted Wnts to their receptors. With the mammalian genome encoding multiple Wnts and Wnt receptors, a longstanding question in the field has been how Wnt-receptor specificities are achieved. Emerging from these studies is a picture of exquisite control over Wnt protein production, secretion, distribution, and receptor interactions, culminating in activation of downstream signaling cascades that control a myriad of biological processes. Here we discuss mechanisms by which Wnt protein activities are tuned and illustrate how the multiple layers of regulation can be leveraged for therapeutic interventions in disease.
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Affiliation(s)
- Pooja R Sonavane
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
| | - Karl Willert
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA.
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5
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Tao YX. Molecular chaperones and G protein-coupled receptor maturation and pharmacology. Mol Cell Endocrinol 2020; 511:110862. [PMID: 32389798 DOI: 10.1016/j.mce.2020.110862] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 05/04/2020] [Accepted: 05/05/2020] [Indexed: 12/15/2022]
Abstract
G protein-coupled receptors (GPCRs) are highly conserved versatile signaling molecules located at the plasma membrane that respond to diverse extracellular signals. They regulate almost all physiological processes in the vertebrates. About 35% of current drugs target these receptors. Mutations in these genes have been identified as causes of numerous diseases. The seven transmembrane domain structure of GPCRs implies that the folding of these transmembrane proteins is extremely complicated and difficult. Indeed, many wild type GPCRs are not folded optimally. The most common defect in genetic diseases caused by GPCR mutations is misfolding and failure to reach the plasma membrane where it functions. General molecular chaperones aid the folding of all proteins, including GPCRs, by preventing aggregation, promoting folding and disaggregating small aggregates. Some GPCRs need additional receptor-specific chaperones to assist their folding. Many of these receptor-specific chaperones interact with additional receptors and alter receptor pharmacology, expanding the understanding of these chaperone proteins.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, 36849-5519, USA.
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6
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Wesslowski J, Kozielewicz P, Wang X, Cui H, Schihada H, Kranz D, Karuna M P, Levkin P, Gross JC, Boutros M, Schulte G, Davidson G. eGFP-tagged Wnt-3a enables functional analysis of Wnt trafficking and signaling and kinetic assessment of Wnt binding to full-length Frizzled. J Biol Chem 2020; 295:8759-8774. [PMID: 32381507 PMCID: PMC7324525 DOI: 10.1074/jbc.ra120.012892] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 05/07/2020] [Indexed: 12/13/2022] Open
Abstract
The Wingless/Int1 (Wnt) signaling system plays multiple, essential roles in embryonic development, tissue homeostasis, and human diseases. Although many of the underlying signaling mechanisms are becoming clearer, the binding mode, kinetics, and selectivity of 19 mammalian WNTs to their receptors of the class Frizzled (FZD1–10) remain obscure. Attempts to investigate Wnt-FZD interactions are hampered by the difficulties in working with Wnt proteins and their recalcitrance to epitope tagging. Here, we used a fluorescently tagged version of mouse Wnt-3a for studying Wnt-FZD interactions. We observed that the enhanced GFP (eGFP)-tagged Wnt-3a maintains properties akin to wild-type (WT) Wnt-3a in several biologically relevant contexts. The eGFP-tagged Wnt-3a was secreted in an evenness interrupted (EVI)/Wntless-dependent manner, activated Wnt/β-catenin signaling in 2D and 3D cell culture experiments, promoted axis duplication in Xenopus embryos, stimulated low-density lipoprotein receptor-related protein 6 (LRP6) phosphorylation in cells, and associated with exosomes. Further, we used conditioned medium containing eGFP-Wnt-3a to visualize its binding to FZD and to quantify Wnt-FZD interactions in real time in live cells, utilizing a recently established NanoBRET-based ligand binding assay. In summary, the development of a biologically active, fluorescent Wnt-3a reported here opens up the technical possibilities to unravel the intricate biology of Wnt signaling and Wnt-receptor selectivity.
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Affiliation(s)
- Janine Wesslowski
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Pawel Kozielewicz
- Section of Receptor Biology & Signaling, Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Xianxian Wang
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Haijun Cui
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Hannes Schihada
- Section of Receptor Biology & Signaling, Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Dominique Kranz
- Division of Signaling and Functional Genomics, German Cancer Research Center (DKFZ) and Heidelberg University, Heidelberg, Germany
| | - Pradhipa Karuna M
- Hematology and Oncology/Developmental Biochemistry, University Medical Center Goettingen, Goettingen, Germany
| | - Pavel Levkin
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Julia Christina Gross
- Hematology and Oncology/Developmental Biochemistry, University Medical Center Goettingen, Goettingen, Germany
| | - Michael Boutros
- Division of Signaling and Functional Genomics, German Cancer Research Center (DKFZ) and Heidelberg University, Heidelberg, Germany
| | - Gunnar Schulte
- Section of Receptor Biology & Signaling, Department of Physiology & Pharmacology, Karolinska Institutet, Stockholm, Sweden.
| | - Gary Davidson
- Institute of Biological and Chemical Systems-Functional Molecular Systems (IBCS-FMS), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
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7
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Chen H, Lu C, Ouyang B, Zhang H, Huang Z, Bhatia D, Lee SJ, Shah D, Sura A, Yeh WC, Li Y. Development of Potent, Selective Surrogate WNT Molecules and Their Application in Defining Frizzled Requirements. Cell Chem Biol 2020; 27:598-609.e4. [PMID: 32220333 DOI: 10.1016/j.chembiol.2020.02.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 02/10/2020] [Accepted: 02/27/2020] [Indexed: 01/20/2023]
Abstract
WNTs regulate myriad biological processes during embryonic development and are key regulators of stem cell function, tissue homeostasis, and injury repair in adults. The creation of WNT-based therapies has been hampered by challenges in developing soluble, potent, and selective WNT molecules. Soluble WNT surrogates have been reported, but they demonstrate relatively weak WNT signaling activity. Here, we describe a platform for potent, selective WNT surrogate generation. We identify multivalent binding to Frizzleds (FZDs) and low-density lipoprotein receptor-related proteins (LRPs) to be a requirement for maximal WNT/β-catenin activation. Furthermore, we show that recruitment of two different FZDs together with LRP causes efficient signaling. Surrogate WNT targeting either FZD1,2,7 or FZD5,8 induces expansive growth of intestinal organoids. This flexible WNT surrogate platform yields potent agonists with any desired receptor specificity and will be useful for research and therapeutic applications for tissue regeneration.
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Affiliation(s)
- Hui Chen
- Surrozen Inc., 171 Oyster Point Boulevard, Suite 400, South San Francisco, CA 94080, USA
| | - Chenggang Lu
- Surrozen Inc., 171 Oyster Point Boulevard, Suite 400, South San Francisco, CA 94080, USA
| | - Brian Ouyang
- Surrozen Inc., 171 Oyster Point Boulevard, Suite 400, South San Francisco, CA 94080, USA
| | - Haili Zhang
- Surrozen Inc., 171 Oyster Point Boulevard, Suite 400, South San Francisco, CA 94080, USA
| | - Zhong Huang
- Surrozen Inc., 171 Oyster Point Boulevard, Suite 400, South San Francisco, CA 94080, USA
| | - Diksha Bhatia
- Surrozen Inc., 171 Oyster Point Boulevard, Suite 400, South San Francisco, CA 94080, USA
| | - Sung-Jin Lee
- Surrozen Inc., 171 Oyster Point Boulevard, Suite 400, South San Francisco, CA 94080, USA
| | - Darshini Shah
- Surrozen Inc., 171 Oyster Point Boulevard, Suite 400, South San Francisco, CA 94080, USA
| | - Asmiti Sura
- Surrozen Inc., 171 Oyster Point Boulevard, Suite 400, South San Francisco, CA 94080, USA
| | - Wen-Chen Yeh
- Surrozen Inc., 171 Oyster Point Boulevard, Suite 400, South San Francisco, CA 94080, USA
| | - Yang Li
- Surrozen Inc., 171 Oyster Point Boulevard, Suite 400, South San Francisco, CA 94080, USA.
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8
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Disorders of FZ-CRD; insights towards FZ-CRD folding and therapeutic landscape. Mol Med 2019; 26:4. [PMID: 31892318 PMCID: PMC6938638 DOI: 10.1186/s10020-019-0129-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Accepted: 12/13/2019] [Indexed: 02/08/2023] Open
Abstract
The ER is hub for protein folding. Proteins that harbor a Frizzled cysteine-rich domain (FZ-CRD) possess 10 conserved cysteine motifs held by a unique disulfide bridge pattern which attains a correct fold in the ER. Little is known about implications of disease-causing missense mutations within FZ-CRD families. Mutations in FZ-CRD of Frizzled class receptor 4 (FZD4) and Muscle, skeletal, receptor tyrosine kinase (MuSK) and Receptor tyrosine kinase-like orphan receptor 2 (ROR2) cause Familial Exudative Vitreoretinopathy (FEVR), Congenital Myasthenic Syndrome (CMS), and Robinow Syndrome (RS) respectively. We highlight reported pathogenic inherited missense mutations in FZ-CRD of FZD4, MuSK and ROR2 which misfold, and traffic abnormally in the ER, with ER-associated degradation (ERAD) as a common pathogenic mechanism for disease. Our review shows that all studied FZ-CRD mutants of RS, FEVR and CMS result in misfolded proteins and/or partially misfolded proteins with an ERAD fate, thus we coin them as “disorders of FZ-CRD”. Abnormal trafficking was demonstrated in 17 of 29 mutants studied; 16 mutants were within and/or surrounding the FZ-CRD with two mutants distant from FZ-CRD. These ER-retained mutants were improperly N-glycosylated confirming ER-localization. FZD4 and MuSK mutants were tagged with polyubiquitin chains confirming targeting for proteasomal degradation. Investigating the cellular and molecular mechanisms of these mutations is important since misfolded protein and ER-targeted therapies are in development. The P344R-MuSK kinase mutant showed around 50% of its in-vitro autophosphorylation activity and P344R-MuSK increased two-fold on proteasome inhibition. M105T-FZD4, C204Y-FZD4, and P344R-MuSK mutants are thermosensitive and therefore, might benefit from extending the investigation to a larger number of chemical chaperones and/or proteasome inhibitors. Nonetheless, FZ-CRD ER-lipidation it less characterized in the literature and recent structural data sheds light on the importance of lipidation in protein glycosylation, proper folding, and ER trafficking. Current treatment strategies in-place for the conformational disease landscape is highlighted. From this review, we envision that disorders of FZ-CRD might be receptive to therapies that target FZ-CRD misfolding, regulation of fatty acids, and/or ER therapies; thus paving the way for a newly explored paradigm to treat different diseases with common defects.
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9
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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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10
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Hansen S, Nile AH, Mehta SC, Fuhrmann J, Hannoush RN. Lead Optimization Yields High Affinity Frizzled 7-Targeting Peptides That Modulate Clostridium difficile Toxin B Pathogenicity in Epithelial Cells. J Med Chem 2019; 62:7739-7750. [PMID: 31429553 DOI: 10.1021/acs.jmedchem.9b00500] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Frizzled 7 (FZD7) receptors have been shown to play a central role in intestinal stem cell regeneration and, more recently, in Clostridium difficile pathogenesis. Yet, targeting FZD7 receptors with small ligands has not been explored as an approach to block C. difficile pathogenesis. Here, we report the discovery of high affinity peptides that selectively bind to FZD7 receptors. We describe an integrated approach for lead optimization, utilizing structure-based rational design and directed evolution, to enhance the peptide binding affinity while still maintaining FZD7 receptor selectivity. This work yielded new peptide leads with picomolar binding constants to FZD7 as measured by biophysical methods. The new peptides block the interaction between C. difficile toxin B (TcdB) and FZD receptors and perturb C. difficile pathogenesis in epithelial cells. As such, our findings provide a proof of concept that targeting FZD receptors could be a viable pharmacological approach to protect epithelial cells from TcdB pathogenicity.
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11
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Wnt Binding Affinity Prediction for Putative Frizzled-Type Cysteine-Rich Domains. Int J Mol Sci 2019; 20:ijms20174168. [PMID: 31454915 PMCID: PMC6747125 DOI: 10.3390/ijms20174168] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 08/22/2019] [Accepted: 08/22/2019] [Indexed: 12/25/2022] Open
Abstract
Several proteins other than the frizzled receptors (Fzd) and the secreted Frizzled-related proteins (sFRP) contain Fzd-type cysteine-rich domains (CRD). We have termed these domains “putative Fzd-type CRDs”, as the relevance of Wnt signalling in the majority of these is unknown; the RORs, an exception to this, are well known for mediating non-canonical Wnt signalling. In this study, we have predicted the likely binding affinity of all Wnts for all putative Fzd-type CRDs. We applied both our previously determined Wnt‒Fzd CRD binding affinity prediction model, as well as a newly devised model wherein the lipid term was forced to contribute favourably to the predicted binding energy. The results obtained from our new model indicate that certain putative Fzd CRDs are much more likely to bind Wnts, in some cases exhibiting selectivity for specific Wnts. The results of this study inform the investigation of Wnt signalling modulation beyond Fzds and sFRPs.
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12
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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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13
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Abstract
Wnt signaling regulates physiological processes ranging from cell differentiation to bone formation. Dysregulation of Wnt signaling is linked to several human ailments, including colorectal, pancreatic, and breast cancers. As such, modulation of this pathway has been an attractive strategy for therapeutic development of anticancer agents. Since the discovery of Wnt proteins more than 35 years ago, research efforts continue to focus on understanding the biochemistry of their molecular interactions and their biological functions. Wnt is a secreted glycoprotein covalently modified with a cis-unsaturated fatty acyl group at a conserved serine residue, and this modification is required for Wnt secretion and activity. To initiate signaling, Wnt proteins bind to cell-surface Frizzled (FZD) receptors, but the molecular basis for recognition of Wnt's fatty acyl moiety by the extracellular cysteine-rich domain of FZD has become clear only very recently. Here, we review the most recent developments in the field, focusing on structural and biochemical studies of the FZD receptor family and highlighting new insights into their molecular arrangement and mode of regulation by cis-unsaturated fatty acids. Additionally, we examine how other lipid-binding proteins recognize fatty acyl chains on Wnt proteins in the regulation of Wnt secretion and activities. Altogether, this perspective expands our understanding of fatty acid–protein interactions in the FZD system and provides a basis for guiding future research in the field.
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Affiliation(s)
- Aaron H Nile
- From the Department of Early Discovery Biochemistry, Genentech, South San Francisco, California 94080
| | - Rami N Hannoush
- From the Department of Early Discovery Biochemistry, Genentech, South San Francisco, California 94080
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Schulte G, Wright SC. Frizzleds as GPCRs - More Conventional Than We Thought! Trends Pharmacol Sci 2018; 39:828-842. [PMID: 30049420 DOI: 10.1016/j.tips.2018.07.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/27/2018] [Accepted: 07/02/2018] [Indexed: 01/14/2023]
Abstract
For more than 30 years, WNT/β-catenin and planar cell polarity signaling has formed the basis for what we understand to be the primary output of the interaction between WNTs and their cognate receptors known as Frizzleds (FZDs). In the shadow of these pathways, evidence for the involvement of heterotrimeric G proteins in WNT signaling has grown substantially over the years - redefining the complexity of the WNT signaling network. Moreover, the distinct characteristics of FZD paralogs are becoming better understood, and we can now apply concepts valid for classical GPCRs to grasp FZDs as molecular machines at the interface of ligand binding and intracellular effects. This review discusses recent developments in the field of WNT/FZD signaling in the context of GPCR pharmacology, and identifies remaining mysteries with an emphasis on structural and kinetic components that support this dogma shift.
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Affiliation(s)
- Gunnar Schulte
- Section of Receptor Biology and Signaling, Department of Physiology and Pharmacology, Biomedicum 6D, Tomtebodavägen 16, Karolinska Institutet, S-171 65 Stockholm, Sweden.
| | - Shane C Wright
- Section of Receptor Biology and Signaling, Department of Physiology and Pharmacology, Biomedicum 6D, Tomtebodavägen 16, Karolinska Institutet, S-171 65 Stockholm, Sweden
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15
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Oligomerization of a G protein-coupled receptor in neurons controlled by its structural dynamics. Sci Rep 2018; 8:10414. [PMID: 29991736 PMCID: PMC6039492 DOI: 10.1038/s41598-018-28682-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 06/26/2018] [Indexed: 12/16/2022] Open
Abstract
G protein coupled receptors (GPCRs) play essential roles in intercellular communication. Although reported two decades ago, the assembly of GPCRs into dimer and larger oligomers in their native environment is still a matter of intense debate. Here, using number and brightness analysis of fluorescently labeled receptors in cultured hippocampal neurons, we confirm that the metabotropic glutamate receptor type 2 (mGlu2) is a homodimer at expression levels in the physiological range, while heterodimeric GABAB receptors form larger complexes. Surprisingly, we observed the formation of larger mGlu2 oligomers upon both activation and inhibition of the receptor. Stabilizing the receptor in its inactive conformation using biochemical constraints also led to the observation of oligomers. Following our recent observation that mGlu receptors are in constant and rapid equilibrium between several states under basal conditions, we propose that this structural heterogeneity limits receptor oligomerization. Such assemblies are expected to stabilize either the active or the inactive state of the receptor.
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16
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TSPAN12 Is a Norrin Co-receptor that Amplifies Frizzled4 Ligand Selectivity and Signaling. Cell Rep 2018; 19:2809-2822. [PMID: 28658627 DOI: 10.1016/j.celrep.2017.06.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 03/29/2017] [Accepted: 05/27/2017] [Indexed: 11/23/2022] Open
Abstract
Accessory proteins in Frizzled (FZD) receptor complexes are thought to determine ligand selectivity and signaling amplitude. Genetic evidence indicates that specific combinations of accessory proteins and ligands mediate vascular β-catenin signaling in different CNS structures. In the retina, the tetraspanin TSPAN12 and the ligand norrin (NDP) mediate angiogenesis, and both genes are linked to familial exudative vitreoretinopathy (FEVR), yet the molecular function of TSPAN12 remains poorly understood. Here, we report that TSPAN12 is an essential component of the NDP receptor complex and interacts with FZD4 and NDP via its extracellular loops, consistent with an action as co-receptor that enhances FZD4 ligand selectivity for NDP. FEVR-linked mutations in TSPAN12 prevent the incorporation of TSPAN12 into the NDP receptor complex. In vitro and in Xenopus embryos, TSPAN12 alleviates defects of FZD4 M105V, a mutation that destabilizes the NDP/FZD4 interaction. This study sheds light on the poorly understood function of accessory proteins in FZD signaling.
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17
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Abstract
Wnt/β-catenin signaling is crucial for adult homeostasis and stem cell maintenance, and its dysregulation is strongly associated to cancer. Upon Wnt binding, Wnt receptors assemble into large complexes called signalosomes that provide a platform for interactions with downstream effector proteins. The assembly and regulation of these signalosomes remains largely elusive. Here, we use internally tagged Wnt ligands as a tool to isolate and analyze the composition and regulation of endogenous Wnt receptor complexes. We identify a positive regulator of Wnt signaling that facilitates signalosome formation by promoting intramembrane receptor interactions. Our results reveal that the assembly of multiprotein Wnt signalosomes proceeds along well-ordered steps and involves regulated intramembrane interactions. Wnt/β-catenin signaling controls development and adult tissue homeostasis by regulating cell proliferation and cell fate decisions. Wnt binding to its receptors Frizzled (FZD) and low-density lipoprotein-related 6 (LRP6) at the cell surface initiates a signaling cascade that leads to the transcription of Wnt target genes. Upon Wnt binding, the receptors assemble into large complexes called signalosomes that provide a platform for interactions with downstream effector proteins. The molecular basis of signalosome formation and regulation remains elusive, largely due to the lack of tools to analyze its endogenous components. Here, we use internally tagged Wnt3a proteins to isolate and characterize activated, endogenous Wnt receptor complexes by mass spectrometry-based proteomics. We identify the single-span membrane protein TMEM59 as an interactor of FZD and LRP6 and a positive regulator of Wnt signaling. Mechanistically, TMEM59 promotes the formation of multimeric Wnt–FZD assemblies via intramembrane interactions. Subsequently, these Wnt–FZD–TMEM59 clusters merge with LRP6 to form mature Wnt signalosomes. We conclude that the assembly of multiprotein Wnt signalosomes proceeds along well-ordered steps that involve regulated intramembrane interactions.
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18
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Saito-Diaz K, Benchabane H, Tiwari A, Tian A, Li B, Thompson JJ, Hyde AS, Sawyer LM, Jodoin JN, Santos E, Lee LA, Coffey RJ, Beauchamp RD, Williams CS, Kenworthy AK, Robbins DJ, Ahmed Y, Lee E. APC Inhibits Ligand-Independent Wnt Signaling by the Clathrin Endocytic Pathway. Dev Cell 2018; 44:566-581.e8. [PMID: 29533772 PMCID: PMC5884143 DOI: 10.1016/j.devcel.2018.02.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 01/02/2018] [Accepted: 02/13/2018] [Indexed: 01/02/2023]
Abstract
Adenomatous polyposis coli (APC) mutations cause Wnt pathway activation in human cancers. Current models for APC action emphasize its role in promoting β-catenin degradation downstream of Wnt receptors. Unexpectedly, we find that blocking Wnt receptor activity in APC-deficient cells inhibits Wnt signaling independently of Wnt ligand. We also show that inducible loss of APC is rapidly followed by Wnt receptor activation and increased β-catenin levels. In contrast, APC2 loss does not promote receptor activation. We show that APC exists in a complex with clathrin and that Wnt pathway activation in APC-deficient cells requires clathrin-mediated endocytosis. Finally, we demonstrate conservation of this mechanism in Drosophila intestinal stem cells. We propose a model in which APC and APC2 function to promote β-catenin degradation, and APC also acts as a molecular "gatekeeper" to block receptor activation via the clathrin pathway.
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Affiliation(s)
- Kenyi Saito-Diaz
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Hassina Benchabane
- Department of Molecular and Systems Biology and the Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth College, Hanover, NH 03755, USA
| | - Ajit Tiwari
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Ai Tian
- Department of Molecular and Systems Biology and the Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth College, Hanover, NH 03755, USA
| | - Bin Li
- Molecular Oncology Program, Division of Surgical Oncology, Dewitt Daughtry Family Department of Surgery, and Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Joshua J Thompson
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Annastasia S Hyde
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Leah M Sawyer
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Jeanne N Jodoin
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Eduardo Santos
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Laura A Lee
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Robert J Coffey
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - R Daniel Beauchamp
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Surgery, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Christopher S Williams
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Anne K Kenworthy
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - David J Robbins
- Molecular Oncology Program, Division of Surgical Oncology, Dewitt Daughtry Family Department of Surgery, and Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, FL 33136, USA
| | - Yashi Ahmed
- Department of Molecular and Systems Biology and the Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth College, Hanover, NH 03755, USA.
| | - Ethan Lee
- Department of Cell & Developmental Biology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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19
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Hoseth EZ, Krull F, Dieset I, Mørch RH, Hope S, Gardsjord ES, Steen NE, Melle I, Brattbakk HR, Steen VM, Aukrust P, Djurovic S, Andreassen OA, Ueland T. Exploring the Wnt signaling pathway in schizophrenia and bipolar disorder. Transl Psychiatry 2018; 8:55. [PMID: 29507296 PMCID: PMC5838215 DOI: 10.1038/s41398-018-0102-1] [Citation(s) in RCA: 78] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/28/2017] [Accepted: 12/05/2017] [Indexed: 01/05/2023] Open
Abstract
The Wnt signaling pathway plays a crucial role in neurodevelopment and in regulating the function and structure of the adult nervous system. Schizophrenia (SCZ) and bipolar disorder (BD) are severe mental disorders with evidence of subtle neurodevelopmental, structural and functional neuronal abnormalities. We aimed to elucidate the role of aberrant regulation of the Wnt system in these disorders by evaluating plasma levels of secreted Wnt modulators in patients (SCZ = 551 and BD = 246) and healthy controls (HCs = 639) using enzyme immune-assay. We also investigated the expression of 141 Wnt-related genes in whole blood in a subsample (SCZ = 338, BD = 241, and HCs = 263) using microarray analysis. Both SCZ and BD had dysregulated mRNA expression of Wnt-related genes favoring attenuated canonical (beta-catenin-dependent) signaling, and there were also indices of enhanced non-canonical Wnt signaling. In particular, FZD7, which may activate all Wnt pathways, but favors non-canonical signaling, and NFATc3, a downstream transcription factor and readout of the non-canonical Wnt/Ca2+ pathway, were significantly increased in SCZ and BD (p < 3 × 10-4). Furthermore, patients had lower plasma levels of soluble dickkopf 1 and sclerostin (p < 0.01) compared with HC. Our findings suggest that SCZ and BD are characterized by abnormal Wnt gene expression and plasma protein levels, and we propose that drugs targeting the Wnt pathway may have a role in the treatment of severe mental disorders.
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Affiliation(s)
- Eva Z. Hoseth
- 0000 0004 0389 8485grid.55325.34NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway ,Division of Mental Health and Addiction, Møre and Romsdal Hospital Trust, Kristiansund, Norway
| | - Florian Krull
- 0000 0004 0389 8485grid.55325.34NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Ingrid Dieset
- 0000 0004 0389 8485grid.55325.34NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Ragni H. Mørch
- 0000 0004 0389 8485grid.55325.34NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Sigrun Hope
- 0000 0004 0389 8485grid.55325.34NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway ,0000 0004 0389 8485grid.55325.34Departent of Neurohabilitation, Division of Neurology, Oslo University Hospital, Oslo, Norway
| | - Erlend S. Gardsjord
- 0000 0004 0389 8485grid.55325.34NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Nils Eiel Steen
- 0000 0004 0389 8485grid.55325.34NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Ingrid Melle
- 0000 0004 0389 8485grid.55325.34NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Hans-Richard Brattbakk
- 0000 0004 1936 7443grid.7914.bNORMENT, KG Jebsen Centre for Psychosis Research, Department of Clinical Science, University of Bergen, Oslo, Norway ,0000 0000 9753 1393grid.412008.fDr. Einar Martens Research Group for Biological Psychiatry, Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Oslo, Norway
| | - Vidar M. Steen
- 0000 0004 1936 7443grid.7914.bNORMENT, KG Jebsen Centre for Psychosis Research, Department of Clinical Science, University of Bergen, Oslo, Norway ,0000 0000 9753 1393grid.412008.fDr. Einar Martens Research Group for Biological Psychiatry, Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Oslo, Norway
| | - Pål Aukrust
- 0000 0004 0389 8485grid.55325.34Research Institute for Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway ,0000 0004 0389 8485grid.55325.34Section of Clinical Immunology and Infectious Diseases, Oslo University Hospital Rikshospitalet, Oslo, Norway ,0000 0004 0389 8485grid.55325.34Instiute of Clinical Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway ,0000 0004 1936 8921grid.5510.1K.G. Jensen Inflammatory Research Center, University of Oslo, Oslo, Norway
| | - Srdjan Djurovic
- 0000 0004 0389 8485grid.55325.34Department of Medical Genetics, Oslo University Hospital, Oslo, Norway ,0000 0004 1936 7443grid.7914.bNORMENT, KG Jebsen Centre for Psychosis Research, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Ole A. Andreassen
- 0000 0004 0389 8485grid.55325.34NORMENT, KG Jebsen Centre for Psychosis Research, Institute of Clinical Medicine, University of Oslo, and Division of Mental Health and Addiction, Oslo University Hospital, Oslo, Norway
| | - Thor Ueland
- Research Institute for Internal Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway. .,Instiute of Clinical Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway. .,K.G. Jensen Inflammatory Research Center, University of Oslo, Oslo, Norway. .,K. G. Jebsen Thrombosis Research and Expertise Center, University of Tromsø, Tromsø, Norway.
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20
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DeBruine ZJ, Xu HE, Melcher K. Assembly and architecture of the Wnt/β-catenin signalosome at the membrane. Br J Pharmacol 2017; 174:4564-4574. [PMID: 28941231 DOI: 10.1111/bph.14048] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 09/05/2017] [Accepted: 09/11/2017] [Indexed: 12/21/2022] Open
Abstract
Wnt/β-catenin signalling is initiated by a ternary Wnt-Frizzled (FZD)-LDL receptor-related protein (LRP) 5/6 binding event. The resulting conformational changes in the FZD and LRP5/6 receptors promote the assembly of an intracellular signalosome driven by Dishevelled and Axin co-polymerization. Recent evidence suggests that the FZD receptor and LRP5/6 participate in the assembly of this signalosome by forming regulatory scaffolds for stabilizing Dishevelled and Axin adapters. In this review, we focus on the contributions of Wnts and their receptors in the assembly of the signalosome. We present an emerging model, which unifies Wnt receptor oligomerization with intracellular signalosome formation, and then discuss how FZD receptors might be targeted to either disrupt or enhance their capacity as a dynamic sensor of Wnt binding. LINKED ARTICLES This article is part of a themed section on WNT Signalling: Mechanisms and Therapeutic Opportunities. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.24/issuetoc.
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Affiliation(s)
- Zachary J DeBruine
- Center for Cancer and Cell Biology, Laboratory for Structural Biology and Biochemistry, Van Andel Research Institute, Grand Rapids, MI, USA
| | - H E Xu
- Center for Cancer and Cell Biology, Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, MI, USA.,Van Andel Research Institute/Shanghai Institute of Materia Medica Center, Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Karsten Melcher
- Center for Cancer and Cell Biology, Laboratory for Structural Biology and Biochemistry, Van Andel Research Institute, Grand Rapids, MI, USA
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21
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Defining the molecular basis of interaction between R3 receptor-type protein tyrosine phosphatases and VE-cadherin. PLoS One 2017; 12:e0184574. [PMID: 28926625 PMCID: PMC5604967 DOI: 10.1371/journal.pone.0184574] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 08/26/2017] [Indexed: 11/19/2022] Open
Abstract
Receptor-type protein tyrosine phosphatases (RPTPs) of the R3 subgroup play key roles in the immune, vascular and nervous systems. They are characterised by a large ectodomain comprising multiple FNIII-like repeats, a transmembrane domain, and a single intracellular phosphatase domain. The functional role of the extracellular region has not been clearly defined and potential roles in ligand interaction, dimerization, and regulation of cell-cell contacts have been reported. Here bimolecular fluorescence complementation (BiFC) in live cells was used to examine the molecular basis for the interaction of VE-PTP with VE-cadherin, two proteins involved in endothelial cell contact and maintenance of vascular integrity. The potential of other R3-PTPs to interact with VE-cadherin was also explored using this method. Quantitative BiFC analysis, using a VE-PTP construct expressing only the ectodomain and transmembrane domain, revealed a specific interaction with VE-cadherin, when compared with controls. Controls were sialophorin, an unrelated membrane protein with a large ectodomain, and a membrane anchored C-terminal Venus-YFP fragment, lacking both ectodomain and transmembrane domains. Truncation of the first 16 FNIII-like repeats from the ectodomain of VE-PTP indicated that removal of this region is not sufficient to disrupt the interaction with VE-cadherin, although it occurs predominantly in an intracellular location. A construct with a deletion of only the 17th domain of VE-PTP was, in contrast to previous studies, still able to interact with VE-cadherin, although this also was predominantly intracellular. Other members of the R3-PTP family (DEP-1, GLEPP1 and SAP-1) also exhibited the potential to interact with VE-cadherin. The direct interaction of DEP-1 with VE-cadherin is likely to be of physiological relevance since both proteins are expressed in endothelial cells. Together the data presented in the study suggest a role for both the ectodomain and transmembrane domain of R3-PTPs in interaction with VE-cadherin.
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22
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Agonist-induced dimer dissociation as a macromolecular step in G protein-coupled receptor signaling. Nat Commun 2017; 8:226. [PMID: 28790300 PMCID: PMC5548745 DOI: 10.1038/s41467-017-00253-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 06/14/2017] [Indexed: 01/28/2023] Open
Abstract
G protein-coupled receptors (GPCRs) constitute the largest family of cell surface receptors. They can exist and act as dimers, but the requirement of dimers for agonist-induced signal initiation and structural dynamics remains largely unknown. Frizzled 6 (FZD6) is a member of Class F GPCRs, which bind WNT proteins to initiate signaling. Here, we show that FZD6 dimerizes and that the dimer interface of FZD6 is formed by the transmembrane α-helices four and five. Most importantly, we present the agonist-induced dissociation/re-association of a GPCR dimer through the use of live cell imaging techniques. Further analysis of a dimerization-impaired FZD6 mutant indicates that dimer dissociation is an integral part of FZD6 signaling to extracellular signal-regulated kinases1/2. The discovery of agonist-dependent dynamics of dimers as an intrinsic process of receptor activation extends our understanding of Class F and other dimerizing GPCRs, offering novel targets for dimer-interfering small molecules. Frizzled 6 (FZD6) is a G protein-coupled receptor (GPCR) involved in several cellular processes. Here, the authors use live cell imaging and spectroscopy to show that FZD6 forms dimers, whose association is regulated by WNT proteins and that dimer dissociation is crucial for FZD6 signaling.
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23
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Genotype-Phenotype Characterization of Novel Variants in Six Italian Patients with Familial Exudative Vitreoretinopathy. J Ophthalmol 2017; 2017:3080245. [PMID: 28758032 PMCID: PMC5516747 DOI: 10.1155/2017/3080245] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 06/04/2017] [Indexed: 12/26/2022] Open
Abstract
Familial exudative vitreoretinopathy (FEVR) is a complex disorder characterized by incomplete development of the retinal vasculature. Here, we report the results obtained on the spectrum of genetic variations and correlated phenotypes found in a cohort of Italian FEVR patients. Eight probands (age range 7–19 years) were assessed by genetic analysis and comprehensive age-appropriate ophthalmic examination. Genetic testing investigated the genes most widely associated in literature with FEVR: FZD4, LRP5, TSPAN12, and NDP. Clinical and genetic evaluations were extended to relatives of probands positive to genetic testing. Six out of eight probands (75%) showed a genetic variation probably related to the phenotype. We identified four novel genetic variants, one variant already described in association with Norrie disease and one previously described linked to autosomal dominant FEVR. Pedigree analysis of patients led to the classification of four autosomal dominant cases of FEVR (caused by FZD4 and TSPAN12 variants) and two X-linked FEVR probands (NDP variants). None of the patients showed variants in the LRP5 gene. This study represents the largest cohort study in Italian FEVR patients. Our findings are in agreement with the previous literature confirming that FEVR is a clinically and genetically heterogeneous retinal disorder, even when it manifests in the same family.
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Unsaturated fatty acyl recognition by Frizzled receptors mediates dimerization upon Wnt ligand binding. Proc Natl Acad Sci U S A 2017; 114:4147-4152. [PMID: 28377511 DOI: 10.1073/pnas.1618293114] [Citation(s) in RCA: 82] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Frizzled (FZD) receptors mediate Wnt signaling in diverse processes ranging from bone growth to stem cell activity. Moreover, high FZD receptor expression at the cell surface contributes to overactive Wnt signaling in subsets of pancreatic, ovarian, gastric, and colorectal tumors. Despite the progress in biochemical understanding of Wnt-FZD receptor interactions, the molecular basis for recognition of Wnt cis-unsaturated fatty acyl groups by the cysteine-rich domain (CRD) of FZD receptors remains elusive. Here, we determined a crystal structure of human FZD7 CRD unexpectedly bound to a 24-carbon fatty acid. We also report a crystal structure of human FZD5 CRD bound to C16:1 cis-Δ9 unsaturated fatty acid. Both structures reveal a dimeric arrangement of the CRD. The lipid-binding groove exhibits flexibility and spans both monomers, adopting a U-shaped geometry that accommodates the fatty acid. Re-evaluation of the published mouse FZD8 CRD structure reveals that it also shares the same architecture as FZD5 and FZD7 CRDs. Our results define a common molecular mechanism for recognition of the cis-unsaturated fatty acyl group, a necessary posttranslational modification of Wnts, by multiple FZD receptors. The fatty acid bridges two CRD monomers, implying that Wnt binding mediates FZD receptor dimerization. Our data uncover possibilities for the arrangement of Wnt-FZD CRD complexes and shed structural insights that could aide in the identification of pharmacological strategies to modulate FZD receptor function.
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25
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Daulat AM, Borg JP. Wnt/Planar Cell Polarity Signaling: New Opportunities for Cancer Treatment. Trends Cancer 2017; 3:113-125. [PMID: 28718442 DOI: 10.1016/j.trecan.2017.01.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/29/2016] [Accepted: 01/02/2017] [Indexed: 01/08/2023]
Abstract
Cancer cells are addicted to a large spectrum of extracellular cues implicated in initiation, stem cell renewal, tumor growth, dissemination in the body, and resistance to treatment. Wingless/Int-1 (Wnt) ligands and their associated signaling cascades contribute to most of these processes, paving the way for opportunities in therapeutic development. The developmental Wnt/planar cell polarity (PCP) pathway is the most recently described branch of Wnt signaling strongly implicated in cancer development at early and late stages. We describe here some of the latest knowledge accumulated on this pathway and the pending questions, present the most convincing findings about its role in cancer, and review the most promising strategies currently designed to target its components.
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Affiliation(s)
- Avais M Daulat
- Centre de Recherche en Cancérologie de Marseille, Aix Marseille Univ UM105, Inst Paoli-Calmettes, UMR7258 CNRS, U1068 INSERM, 'Cell Polarity, Cell Signalling, and Cancer - Equipe Labellisée Ligue Contre le Cancer', Marseille, France
| | - Jean-Paul Borg
- Centre de Recherche en Cancérologie de Marseille, Aix Marseille Univ UM105, Inst Paoli-Calmettes, UMR7258 CNRS, U1068 INSERM, 'Cell Polarity, Cell Signalling, and Cancer - Equipe Labellisée Ligue Contre le Cancer', Marseille, France.
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26
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Ciano M, Allocca S, Ciardulli MC, Della Volpe L, Bonatti S, D'Agostino M. Differential phosphorylation-based regulation of αB-crystallin chaperone activity for multipass transmembrane proteins. Biochem Biophys Res Commun 2016; 479:325-330. [PMID: 27641668 PMCID: PMC5053547 DOI: 10.1016/j.bbrc.2016.09.071] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 09/14/2016] [Indexed: 01/07/2023]
Abstract
We have previously shown that αB-crystallin (CRYAB), a small heat shock protein (sHsp) that prevents irreversible aggregation of unfolded protein by an ATP-independent chaperone activity, plays a pivotal role in the biogenesis of multipass transmembrane proteins (TMPs) assisting their folding from the cytosolic side of the endoplasmic reticulum (ER) (D'Agostino et al., 2013). Here we present evidence, based on phosphomimetic substitutions, that the three phosphorytable serine residues at position 19, 45 and 59 of CRYAB play a different regulatory role in this novel chaperone activity: S19 and S45 have a strong inhibitory effect, either alone or in combination, while S59 has not and counteracts the inhibition caused by single phosphomimetic substitutions at S19 and S45. Interestingly, all phosphomimetic substitutions determine the formation of smaller oligomeric complexes containing CRYAB, indicating that the inhibitory effect seen for S19 and S45 cannot be ascribed to the reduction of oligomerization frequently associated to a decreased chaperone activity. These results indicate that phosphorylation finely regulates the chaperone activity of CRYAB with multipass TMPs and suggest a pivotal role for S59 in this process. CRYAB chaperone activity toward ATP7B-H1069Q and Fz4-FEVR. Phosphomimetic S19D and S45D inhibit CRYAB chaperone activity. Phosphomimetic S59D protects CRYAB chaperone activity. Pseudo-phosphorylation decreases CRYAB oligomerization.
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Affiliation(s)
- Michela Ciano
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Simona Allocca
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Maria Camilla Ciardulli
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Lucrezia Della Volpe
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Stefano Bonatti
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy.
| | - Massimo D'Agostino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
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Identification of novel candidate drivers connecting different dysfunctional levels for lung adenocarcinoma using protein-protein interactions and a shortest path approach. Sci Rep 2016; 6:29849. [PMID: 27412431 PMCID: PMC4944139 DOI: 10.1038/srep29849] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 06/24/2016] [Indexed: 12/21/2022] Open
Abstract
Tumors are formed by the abnormal proliferation of somatic cells with disordered growth regulation under the influence of tumorigenic factors. Recently, the theory of “cancer drivers” connects tumor initiation with several specific mutations in the so-called cancer driver genes. According to the differentiation of four basic levels between tumor and adjacent normal tissues, the cancer drivers can be divided into the following: (1) Methylation level, (2) microRNA level, (3) mutation level, and (4) mRNA level. In this study, a computational method is proposed to identify novel lung adenocarcinoma drivers based on dysfunctional genes on the methylation, microRNA, mutation and mRNA levels. First, a large network was constructed using protein-protein interactions. Next, we searched all of the shortest paths connecting dysfunctional genes on different levels and extracted new candidate genes lying on these paths. Finally, the obtained candidate genes were filtered by a permutation test and an additional strict selection procedure involving a betweenness ratio and an interaction score. Several candidate genes remained, which are deemed to be related to two different levels of cancer. The analyses confirmed our assertions that some have the potential to contribute to the tumorigenesis process on multiple levels.
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Musada GR, Syed H, Jalali S, Chakrabarti S, Kaur I. Mutation spectrum of the FZD-4, TSPAN12 AND ZNF408 genes in Indian FEVR patients. BMC Ophthalmol 2016; 16:90. [PMID: 27316669 PMCID: PMC4912735 DOI: 10.1186/s12886-016-0236-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 05/10/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Mutations in candidate genes that encode for a ligand (NDP) and receptor complex (FZD4, LRP5 and TSPAN12) in the Norrin β-catenin signaling pathway are involved in the pathogenesis of familial exudative vitreoretinopathy (FEVR, MIM # 133780). Recently, a transcription factor (ZNF408) has also been implicated in FEVR. We had earlier characterized the variations in NDP among FEVR patients from India. The present study aimed at understanding the involvement of the remaining genes (FZD4, TSPAN12 and ZNF408) in the same cohort. METHODS The DNA of 110 unrelated FEVR patients and 115 unaffected controls were screened for variations in the entire coding and untranslated regions of these 3 genes by resequencing. Segregation of the disease-associated variants was assessed in the family members of the probands. The effect of the observed missense changes were further analyzed by SIFT and PolyPhen-2 scores. RESULTS The screening of FZD4, TSPAN12 and ZNF408 genes identified 11 different mutations in 15/110 FEVR probands. Of the 11 identified mutations, 6 mutations were novel. The detected missense mutations were mainly located in the domains which are functionally crucial for the formation of ligand-receptor complex and as they replaced evolutionarily highly conserved amino acids with a SIFT score < 0.005, they are predicted to be pathogenic. Additionally 2 novel and 16 reported single nucleotide polymorphisms (SNP) were also detected. CONCLUSIONS Our genetic screening revealed varying mutation frequencies in the FZD4 (8.0 %), TSPAN12 (5.4 %) and ZNF408 (2.7 %) genes among the FEVR patients, indicating their potential role in the disease pathogenesis. The observed mutations segregated with the disease phenotype and exhibited variable expressivity. The mutations in FZD4 and TSPAN12 were involved in autosomal dominant and autosomal recessive families and further validates the involvement of these gene in FEVR development.
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Affiliation(s)
- Ganeswara Rao Musada
- Kallam Anji Reddy Molecular Genetics Laboratory, Brien Holden Eye Research Centre, L V Prasad Eye Institute (KAR Campus), Road#2, Banjara Hills, Hyderabad, 500034, India
| | - Hameed Syed
- Kallam Anji Reddy Molecular Genetics Laboratory, Brien Holden Eye Research Centre, L V Prasad Eye Institute (KAR Campus), Road#2, Banjara Hills, Hyderabad, 500034, India
| | - Subhadra Jalali
- Smt. Kanuri Santhamma Centre for Vitreo Retinal Diseases, LV Prasad Eye Institute, Hyderabad, India
| | - Subhabrata Chakrabarti
- Kallam Anji Reddy Molecular Genetics Laboratory, Brien Holden Eye Research Centre, L V Prasad Eye Institute (KAR Campus), Road#2, Banjara Hills, Hyderabad, 500034, India
| | - Inderjeet Kaur
- Kallam Anji Reddy Molecular Genetics Laboratory, Brien Holden Eye Research Centre, L V Prasad Eye Institute (KAR Campus), Road#2, Banjara Hills, Hyderabad, 500034, India.
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Frizzled7: A Promising Achilles' Heel for Targeting the Wnt Receptor Complex to Treat Cancer. Cancers (Basel) 2016; 8:cancers8050050. [PMID: 27196929 PMCID: PMC4880867 DOI: 10.3390/cancers8050050] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/03/2016] [Accepted: 05/09/2016] [Indexed: 02/07/2023] Open
Abstract
Frizzled7 is arguably the most studied member of the Frizzled family, which are the cognate Wnt receptors. Frizzled7 is highly conserved through evolution, from Hydra through to humans, and is expressed in diverse organisms, tissues and human disease contexts. Frizzled receptors can homo- or hetero-polymerise and associate with several co-receptors to transmit Wnt signalling. Notably, Frizzled7 can transmit signalling via multiple Wnt transduction pathways and bind to several different Wnt ligands, Frizzled receptors and co-receptors. These promiscuous binding and functional properties are thought to underlie the pivotal role Frizzled7 plays in embryonic developmental and stem cell function. Recent studies have identified that Frizzled7 is upregulated in diverse human cancers, and promotes proliferation, progression and invasion, and orchestrates cellular transitions that underscore cancer metastasis. Importantly, Frizzled7 is able to regulate Wnt signalling activity even in cancer cells which have mutations to down-stream signal transducers. In this review we discuss the various aspects of Frizzled7 signalling and function, and the implications these have for therapeutic targeting of Frizzled7 in cancer.
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Abstract
Wnt signaling encompasses multiple and complex signaling cascades and is involved in many developmental processes such as tissue patterning, cell fate specification, and control of cell division. Consequently, accurate regulation of signaling activities is essential for proper embryonic development. Wnt signaling is mostly silent in the healthy adult organs but a reactivation of Wnt signaling is generally observed under pathological conditions. This has generated increasing interest in this pathway from a therapeutic point of view. In this review article, the involvement of Wnt signaling in cardiovascular development will be outlined, followed by its implication in myocardial infarct healing, cardiac hypertrophy, heart failure, arrhythmias, and atherosclerosis. The initial experiments not always offer consensus on the effects of activation or inactivation of the pathway, which may be attributed to (i) the type of cardiac disease, (ii) timing of the intervention, and (iii) type of cells that are targeted. Therefore, more research is needed to determine the exact implication of Wnt signaling in the conditions mentioned above to exploit it as a powerful therapeutic target.
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Chang TH, Hsieh FL, Zebisch M, Harlos K, Elegheert J, Jones EY. Structure and functional properties of Norrin mimic Wnt for signalling with Frizzled4, Lrp5/6, and proteoglycan. eLife 2015; 4:e06554. [PMID: 26158506 PMCID: PMC4497409 DOI: 10.7554/elife.06554] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Accepted: 06/18/2015] [Indexed: 11/24/2022] Open
Abstract
Wnt signalling regulates multiple processes including angiogenesis, inflammation, and tumorigenesis. Norrin (Norrie Disease Protein) is a cystine-knot like growth factor. Although unrelated to Wnt, Norrin activates the Wnt/β-catenin pathway. Signal complex formation involves Frizzled4 (Fz4), low-density lipoprotein receptor related protein 5/6 (Lrp5/6), Tetraspanin-12 and glycosaminoglycans (GAGs). Here, we report crystallographic and small-angle X-ray scattering analyses of Norrin in complex with Fz4 cysteine-rich domain (Fz4CRD), of this complex bound with GAG analogues, and of unliganded Norrin and Fz4CRD. Our structural, biophysical and cellular data, map Fz4 and putative Lrp5/6 binding sites to distinct patches on Norrin, and reveal a GAG binding site spanning Norrin and Fz4CRD. These results explain numerous disease-associated mutations. Comparison with the Xenopus Wnt8-mouse Fz8CRD complex reveals Norrin mimics Wnt for Frizzled recognition. The production and characterization of wild-type and mutant Norrins reported here open new avenues for the development of therapeutics to combat abnormal Norrin/Wnt signalling.
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Affiliation(s)
- Tao-Hsin Chang
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Fu-Lien Hsieh
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Matthias Zebisch
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Karl Harlos
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - Jonathan Elegheert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
| | - E Yvonne Jones
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford, United Kingdom
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Schulte G. Frizzleds and WNT/β-catenin signaling--The black box of ligand-receptor selectivity, complex stoichiometry and activation kinetics. Eur J Pharmacol 2015; 763:191-5. [PMID: 26003275 DOI: 10.1016/j.ejphar.2015.05.031] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 05/13/2015] [Indexed: 10/23/2022]
Abstract
The lipoglycoproteins of the mammalian WNT family induce β-catenin-dependent signaling through interaction with members of the Class Frizzled receptors and LDL receptor-related protein 5/6 (LRP5/6) albeit with unknown selectivity. The 10 mammalian Frizzleds (FZDs) are seven transmembrane (7TM) spanning receptors and have recently been classified as G protein-coupled receptors (GPCRs). This review summarizes the current knowledge about WNT/FZD selectivity and functional selectivity, the role of co-receptors for signal specification, the formation of receptor complexes as well as the kinetics and mechanisms of signal initiation with focus on WNT/β-catenin signaling. In order to exploit the true therapeutic potential of WNT/FZD signaling to treat human disease, it is clear that substantial progress in the understanding of receptor complex formation and signal specification has to precede a mechanism-based drug design targeting WNT receptors.
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Affiliation(s)
- Gunnar Schulte
- Department of Physiology & Pharmacology, Section of Receptor Biology & Signaling, Karolinska Institutet, S-17177 Stockholm, Sweden; Institute of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czech Republic.
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Pharmacological folding chaperones act as allosteric ligands of Frizzled4. Nat Chem Biol 2015; 11:280-6. [DOI: 10.1038/nchembio.1770] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 02/10/2015] [Indexed: 02/01/2023]
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SUGIYAMA MAI, HASEGAWA HITOKI, ITO SATOKO, SUGIYAMA KAZUYA, MAEDA MASAO, AOKI KOSUKE, WAKABAYASHI TOSHIHIKO, HAMAGUCHI MICHINARI, NATSUME ATSUSHI, SENGA TAKESHI. Paired related homeobox 1 is associated with the invasive properties of glioblastoma cells. Oncol Rep 2014; 33:1123-30. [DOI: 10.3892/or.2014.3681] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 11/13/2014] [Indexed: 11/05/2022] Open
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Familial exudative vitreoretinopathy and related retinopathies. Eye (Lond) 2014; 29:1-14. [PMID: 25323851 DOI: 10.1038/eye.2014.70] [Citation(s) in RCA: 176] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Accepted: 03/05/2014] [Indexed: 12/24/2022] Open
Abstract
Familial exudative vitreoretinopathy (FEVR) is a rare inherited disorder of retinal angiogenesis. Cases can be autosomal dominant, autosomal recessive, or X-linked. FEVR patients have an avascular peripheral retina which, depending on the degree of ischaemia, causes the secondary complications of the disease. Expressivity may be asymmetric and is highly variable. Five genes have been identified that when mutated, cause FEVR; NDP (X-linked), FZD4 (autosomal dominant and recessive), LRP5 (autosomal dominant and recessive), TSPAN12 (autosomal dominant and recessive), and ZNF408 (autosomal dominant). Four of these genes have been shown to have a central role in Norrin/Frizzled4 signalling, suggesting a critical role for this pathway in retinal angiogenesis. In addition to the ocular features, LRP5 mutations can cause osteopenia and osteoporosis. All FEVR patients in whom molecular testing is not easily accessible should have dual energy X-ray absorptiometry (DEXA) scans to assess bone mineral density, as treatment can be initiated to reduce the risk of bone fractures.
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D'Agostino M, Crespi A, Polishchuk E, Generoso S, Martire G, Colombo SF, Bonatti S. ER reorganization is remarkably induced in COS-7 cells accumulating transmembrane protein receptors not competent for export from the endoplasmic reticulum. J Membr Biol 2014; 247:1149-59. [PMID: 25086772 DOI: 10.1007/s00232-014-9710-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 07/15/2014] [Indexed: 10/24/2022]
Abstract
The newly synthesized mutant L501fsX533 Frizzled-4 form and the alpha3beta4 nicotinic acetylcholine receptor expressed in the absence of nicotine accumulate in the endoplasmic reticulum of COS-7 cells and induce the formation of large areas of smooth and highly convoluted cisternae. This results in a generalized block of the transport to the Golgi complex of newly synthesized proteins. Intriguingly, both effects happen peculiarly in COS-7 cells; HeLa, Huh-7, and HEK293 cells expressing the two receptors at similar level than COS-7 cells show normal ER and normal transport toward the plasma membrane. These results question the conclusion that a dominant-negative mechanism would explain the dominance of the mutant L501fsX533 Fz4 allele in the transmission of a form of Familial exudative vitreoretinopathy. Moreover, they indicate that the coordination of endoplasmic reticulum homeostasis in COS-7 cells is particularly error prone. This finding suggests that COS-7 cells may be extremely useful to study the molecular mechanisms regulating endoplasmic reticulum size and architecture.
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Affiliation(s)
- Massimo D'Agostino
- Department of Molecular medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
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38
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Tao YX, Conn PM. Chaperoning G protein-coupled receptors: from cell biology to therapeutics. Endocr Rev 2014; 35:602-47. [PMID: 24661201 PMCID: PMC4105357 DOI: 10.1210/er.2013-1121] [Citation(s) in RCA: 96] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 03/14/2014] [Indexed: 12/13/2022]
Abstract
G protein-coupled receptors (GPCRs) are membrane proteins that traverse the plasma membrane seven times (hence, are also called 7TM receptors). The polytopic structure of GPCRs makes the folding of GPCRs difficult and complex. Indeed, many wild-type GPCRs are not folded optimally, and defects in folding are the most common cause of genetic diseases due to GPCR mutations. Both general and receptor-specific molecular chaperones aid the folding of GPCRs. Chemical chaperones have been shown to be able to correct the misfolding in mutant GPCRs, proving to be important tools for studying the structure-function relationship of GPCRs. However, their potential therapeutic value is very limited. Pharmacological chaperones (pharmacoperones) are potentially important novel therapeutics for treating genetic diseases caused by mutations in GPCR genes that resulted in misfolded mutant proteins. Pharmacoperones also increase cell surface expression of wild-type GPCRs; therefore, they could be used to treat diseases that do not harbor mutations in GPCRs. Recent studies have shown that indeed pharmacoperones work in both experimental animals and patients. High-throughput assays have been developed to identify new pharmacoperones that could be used as therapeutics for a number of endocrine and other genetic diseases.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology, and Pharmacology (Y.-X.T.), College of Veterinary Medicine, Auburn University, Auburn, Alabama 36849-5519; and Departments of Internal Medicine and Cell Biology (P.M.C.), Texas Tech University Health Science Center, Lubbock, Texas 79430-6252
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A disorder-to-order structural transition in the COOH-tail of Fz4 determines misfolding of the L501fsX533-Fz4 mutant. Sci Rep 2014; 3:2659. [PMID: 24036468 PMCID: PMC3773625 DOI: 10.1038/srep02659] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 08/20/2013] [Indexed: 11/08/2022] Open
Abstract
Frizzled 4 belongs to the superfamily of G protein coupled receptors. The unstructured cytosolic tail of the receptor is essential for its activity. The mutation L501fsX533 in the fz4 gene results in a new COOH-tail of the receptor and causes a form of Familial exudative vitreoretinopathy. Here we show that the mutated tail is structured. Two amphipathic helices, displaying affinity for membranes and resembling the structure of Influenza Hemagglutinin fusion peptide, constitute the new fold. This tail induces the aggregation of the receptor in the Endoplasmic Reticulum and it is sufficient to block the export to the Golgi of a chimeric VSVG protein containing the mutated tail. Affecting the tail's structure, net charge or amphipathicity relocates the mutated Fz4 receptor to the Plasma Membrane. Such disorder-to-order structural transition was never described in GPCRs and opens a new scenario on the possible effect of mutations on unstructured regions of proteins.
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40
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Kuwahara A, Sakai H, Xu Y, Itoh Y, Hirabayashi Y, Gotoh Y. Tcf3 represses Wnt-β-catenin signaling and maintains neural stem cell population during neocortical development. PLoS One 2014; 9:e94408. [PMID: 24832538 PMCID: PMC4022625 DOI: 10.1371/journal.pone.0094408] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 03/15/2014] [Indexed: 01/02/2023] Open
Abstract
During mouse neocortical development, the Wnt–β-catenin signaling pathway plays essential roles in various phenomena including neuronal differentiation and proliferation of neural precursor cells (NPCs). Production of the appropriate number of neurons without depletion of the NPC population requires precise regulation of the balance between differentiation and maintenance of NPCs. However, the mechanism that suppresses Wnt signaling to prevent premature neuronal differentiation of NPCs is poorly understood. We now show that the HMG box transcription factor Tcf3 (also known as Tcf7l1) contributes to this mechanism. Tcf3 is highly expressed in undifferentiated NPCs in the mouse neocortex, and its expression is reduced in intermediate neuronal progenitors (INPs) committed to the neuronal fate. We found Tcf3 to be a repressor of Wnt signaling in neocortical NPCs in a reporter gene assay. Tcf3 bound to the promoter of the proneural bHLH gene Neurogenin1 (Neurog1) and repressed its expression. Consistent with this, Tcf3 repressed neuronal differentiation and increased the self-renewal activity of NPCs. We also found that Wnt signal stimulation reduces the level of Tcf3, and increases those of Tcf1 (also known as Tcf7) and Lef1, positive mediators of Wnt signaling, in NPCs. Together, these results suggest that Tcf3 antagonizes Wnt signaling in NPCs, thereby maintaining their undifferentiated state in the neocortex and that Wnt signaling promotes the transition from Tcf3-mediated repression to Tcf1/Lef1-mediated enhancement of Wnt signaling, constituting a positive feedback loop that facilitates neuronal differentiation.
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Affiliation(s)
- Atsushi Kuwahara
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Hiroshi Sakai
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Yuanjiang Xu
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Yasuhiro Itoh
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
| | - Yusuke Hirabayashi
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
- * E-mail:
| | - Yukiko Gotoh
- Laboratory of Cell Signaling, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo, Japan
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Shastry BS. Genetics of familial exudative vitreoretinopathy and its implications for management. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.12.40] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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Ke J, Harikumar KG, Erice C, Chen C, Gu X, Wang L, Parker N, Cheng Z, Xu W, Williams BO, Melcher K, Miller LJ, Xu HE. Structure and function of Norrin in assembly and activation of a Frizzled 4-Lrp5/6 complex. Genes Dev 2013; 27:2305-19. [PMID: 24186977 PMCID: PMC3828517 DOI: 10.1101/gad.228544.113] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Norrin is an important growth factor and Wnt ligand required for angiogenesis in the eye, ear, brain, and female reproductive organs. Structural and functional studies by Ke et al. now reveal that Norrin forms a unique dimer required for binding and activation of the Frizzled 4 (Fz4) receptor. Interestingly, Norrin contains separate binding sites for Wnt ligand coreceptors Lrp5/6 and induces the formation of a ternary complex with Fz4 and Lrp5/6 extracellular domains. This study provides critical new insight into the Wnt and Norrin signaling pathways. Norrin is a cysteine-rich growth factor that is required for angiogenesis in the eye, ear, brain, and female reproductive organs. It functions as an atypical Wnt ligand by specifically binding to the Frizzled 4 (Fz4) receptor. Here we report the crystal structure of Norrin, which reveals a unique dimeric structure with each monomer adopting a conserved cystine knot fold. Functional studies demonstrate that the novel Norrin dimer interface is required for Fz4 activation. Furthermore, we demonstrate that Norrin contains separate binding sites for Fz4 and for the Wnt ligand coreceptor Lrp5 (low-density lipoprotein-related protein 5) or Lrp6. Instead of inducing Fz4 dimerization, Norrin induces the formation of a ternary complex with Fz4 and Lrp5/6 by binding to their respective extracellular domains. These results provide crucial insights into the assembly and activation of the Norrin–Fz4–Lrp5/6 signaling complex.
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Affiliation(s)
- Jiyuan Ke
- Laboratory of Structural Sciences, Van Andel Research Institute, Grand Rapids, Michigan 49503, USA
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Mizumoto K, Shen K. Two Wnts instruct topographic synaptic innervation in C. elegans. Cell Rep 2013; 5:389-96. [PMID: 24139806 DOI: 10.1016/j.celrep.2013.09.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 07/18/2013] [Accepted: 09/09/2013] [Indexed: 11/26/2022] Open
Abstract
Gradients of topographic cues play essential roles in the organization of sensory systems by guiding axonal growth cones. Little is known about whether there are additional mechanisms for precise topographic mapping of synaptic connections. Whereas the C. elegans DA8 and DA9 neurons have similar axonal trajectories, their synapses are positioned in distinct but adjacent domains in the anterior-posterior axis. We found that two Wnts, LIN-44 and EGL-20, are responsible for this spatial organization of synapses. Both Wnts form putative posterior-high, anterior-low gradients. The posteriorly expressed LIN-44 inhibits synapse formation in both DA9 and DA8, and creates a synapse-free domain on both axons via LIN-17 /Frizzled. EGL-20, a more anteriorly expressed Wnt, inhibits synapse formation through MIG-1/Frizzled, which is expressed in DA8 but not in DA9. The Wnt-Frizzled specificity and selective Frizzled expression dictate the stereotyped, topographic positioning of synapses between these two neurons.
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Affiliation(s)
- Kota Mizumoto
- Howard Hughes Medical Institute, Department of Biology, Stanford University, 385 Serra Mall, Stanford, CA 94305, USA
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D'Agostino M, Lemma V, Chesi G, Stornaiuolo M, Cannata Serio M, D'Ambrosio C, Scaloni A, Polishchuk R, Bonatti S. The cytosolic chaperone α-crystallin B rescues folding and compartmentalization of misfolded multispan transmembrane proteins. J Cell Sci 2013; 126:4160-72. [PMID: 23843626 DOI: 10.1242/jcs.125443] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The α-crystallin B chain (CRYAB or HspB5) is a cytosolic chaperone belonging to the small heat shock protein family, which is known to help in the folding of cytosolic proteins. Here we show that CRYAB binds the mutant form of at least two multispan transmembrane proteins (TMPs), exerting an anti-aggregation activity. It rescues the folding of mutant Frizzled4, which is responsible for a rare autosomal dominant form of familial exudative vitreoretinopathy (Fz4-FEVR), and the mutant ATP7B Cu transporter (ATP7B-H1069Q) associated with a common form of Wilson's disease. In the case of Fz4-FEVR, CRYAB prevents the formation of inter-chain disulfide bridges between the lumenal ectodomains of the aggregated mutant chains, which enables correct folding and promotes appropriate compartmentalization on the plasma membrane. ATP7B-H1069Q, with help from CRYAB, folds into the proper conformation, moves to the Golgi complex, and responds to copper overload in the same manner as wild-type ATP7B. These findings strongly suggest that CRYAB plays a pivotal role, previously undetected, in the folding of multispan TMPs and, from the cytosol, is able to orchestrate folding events that take place in the lumen of the ER. Our results contribute to the explanation of the complex scenario behind multispan TMP folding; additionally, they serve to expose interesting avenues for novel therapeutic approaches.
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Affiliation(s)
- Massimo D'Agostino
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, 80131 Naples, Italy
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Wertman J, Dupré DJ. G protein-coupled receptor dimers: look like their parents, but act like teenagers! J Recept Signal Transduct Res 2013; 33:135-8. [PMID: 23323734 DOI: 10.3109/10799893.2012.759591] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
G protein-coupled receptors (GPCRs) represent the largest group of cell surface receptors and an important pharmacological target. Though originally thought to act in a one receptor-one effector fashion, it is now known that these receptors are capable of oligomerization and can function as dimers or higher order oligomers in native tissue. They do not only assemble with identical receptors as homodimers, but also associate with different GPCRs to form heterodimers. We discuss here how heterodimeric GPCRs can assemble, traffic and signal in a manner distinct from their individual receptor components or from homodimers. These receptor pairs are also demonstrated to be regulated by different chaperones, Rabs and scaffolding proteins, further emphasizing their potential as unique targets. We believe in the importance of investigating each GPCR heterodimer as an individual signaling complex, as they appear to act differently from each monomer constituting them. Just as teenagers may resemble their parents and share their genetic makeup, they can still act in a manner that is entirely unique!
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Affiliation(s)
- Jaime Wertman
- Department of Pharmacology, Faculty of Medicine, Sir Charles Tupper Medical Building, Dalhousie University, Halifax, NS, Canada
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Kuang YQ, Charette N, Frazer J, Holland PJ, Attwood KM, Dellaire G, Dupré DJ. Dopamine receptor-interacting protein 78 acts as a molecular chaperone for CCR5 chemokine receptor signaling complex organization. PLoS One 2012; 7:e40522. [PMID: 22815758 PMCID: PMC3398031 DOI: 10.1371/journal.pone.0040522] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Accepted: 06/11/2012] [Indexed: 11/18/2022] Open
Abstract
Chemokine receptors are members of the G protein-coupled receptor (GPCR) family. CCR5 and CXCR4 act as co-receptors for human immunodeficiency virus (HIV) and several efforts have been made to develop ligands to inhibit HIV infection by blocking those receptors. Removal of chemokine receptors from the cell surface using polymorphisms or other means confers some levels of immunity against HIV infection. Up to now, very limited success has been obtained using ligand therapies so we explored potential avenues to regulate chemokine receptor expression at the plasma membrane. We identified a molecular chaperone, DRiP78, that interacts with both CXCR4 and CCR5, but not the heterodimer formed by these receptors. We further characterized the effects of DRiP78 on CCR5 function. We show that the molecular chaperone inhibits CCR5 localization to the plasma membrane. We identified the interaction region on the receptor, the F(x)6LL motif, and show that upon mutation of this motif the chaperone cannot interact with the receptor. We also show that DRiP78 is involved in the assembly of CCR5 chemokine signaling complex as a homodimer, as well as with the Gαi protein. Finally, modulation of DRiP78 levels will affect receptor functions, such as cell migration in cells that endogenously express CCR5. Our results demonstrate that modulation of the functions of a chaperone can affect signal transduction at the cell surface.
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Affiliation(s)
- Yi-Qun Kuang
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Nicholle Charette
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jennifer Frazer
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Patrick J. Holland
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kathleen M. Attwood
- Department of Pathology, Biochemistry and Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Graham Dellaire
- Department of Pathology, Biochemistry and Molecular Biology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Denis J. Dupré
- Department of Pharmacology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada
- * E-mail:
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Comps‐Agrar L, Kniazeff J, Brock C, Trinquet E, Pin J. Stability of GABA
B
receptor oligomers revealed by dual TR‐FRET and drug‐induced cell surface targeting. FASEB J 2012; 26:3430-9. [DOI: 10.1096/fj.12-203646] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Laëtitia Comps‐Agrar
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR)‐5203Institut National de la Santé et de la Recherche Médicale (INSERM) U661 Montpellier France
- Universités Montpellier 1 and 2 Montpellier France
- Cisbio Bioassays Codolet France
| | - Julie Kniazeff
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR)‐5203Institut National de la Santé et de la Recherche Médicale (INSERM) U661 Montpellier France
- Universités Montpellier 1 and 2 Montpellier France
| | - Carsten Brock
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR)‐5203Institut National de la Santé et de la Recherche Médicale (INSERM) U661 Montpellier France
- Universités Montpellier 1 and 2 Montpellier France
| | - Eric Trinquet
- Universités Montpellier 1 and 2 Montpellier France
- Cisbio Bioassays Codolet France
| | - Jean‐Philippe Pin
- Institut de Génomique Fonctionnelle, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR)‐5203Institut National de la Santé et de la Recherche Médicale (INSERM) U661 Montpellier France
- Universités Montpellier 1 and 2 Montpellier France
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Kim SD, Pahuja KB, Ravazzola M, Yoon J, Boyadjiev SA, Hammamoto S, Schekman R, Orci L, Kim J. The [corrected] SEC23-SEC31 [corrected] interface plays critical role for export of procollagen from the endoplasmic reticulum. J Biol Chem 2012; 287:10134-10144. [PMID: 22298774 DOI: 10.1074/jbc.m111.283382] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
COPII proteins are essential for exporting most cargo molecules from the endoplasmic reticulum. The membrane-facing surface of the COPII proteins (especially SEC23-SEC24) interacts directly or indirectly with the cargo molecules destined for exit. As we characterized the SEC23A mutations at the SEC31 binding site identified from patients with cranio-lenticulo-sutural dysplasia, we discovered that the SEC23-SEC31 interface can also influence cargo selection. Remarkably, M702V SEC23A does not compromise COPII assembly, vesicle size, and packaging of cargo molecules into COPII vesicles that we have tested but induces accumulation of procollagen in the endoplasmic reticulum when expressed in normal fibroblasts. We observed that M702V SEC23A activates SAR1B GTPase more than wild-type SEC23A when SEC13-SEC31 is present, indicating that M702V SEC23A causes premature dissociation of COPII from the membrane. Our results indicate that a longer stay of COPII proteins on the membrane is required to cargo procollagen than other molecules and suggest that the SEC23-SEC31 interface plays a critical role in capturing various cargo molecules.
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Affiliation(s)
- Sun-Don Kim
- Section of Genetics, Department of Pediatrics, University of California Davis Medical Center, Sacramento, California 95817
| | - Kanika Bajaj Pahuja
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California Berkeley, Berkeley, California 94720, and
| | - Mariella Ravazzola
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center, 1211 Geneva 4, Switzerland
| | - Joonsik Yoon
- Section of Genetics, Department of Pediatrics, University of California Davis Medical Center, Sacramento, California 95817
| | - Simeon A Boyadjiev
- Section of Genetics, Department of Pediatrics, University of California Davis Medical Center, Sacramento, California 95817
| | - Susan Hammamoto
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California Berkeley, Berkeley, California 94720, and
| | - Randy Schekman
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California Berkeley, Berkeley, California 94720, and
| | - Lelio Orci
- Department of Cell Physiology and Metabolism, University of Geneva Medical Center, 1211 Geneva 4, Switzerland
| | - Jinoh Kim
- Section of Genetics, Department of Pediatrics, University of California Davis Medical Center, Sacramento, California 95817,.
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Katanaev VL, Kryuchkov MV. The eye of Drosophila as a model system for studying intracellular signaling in ontogenesis and pathogenesis. BIOCHEMISTRY (MOSCOW) 2012; 76:1556-81. [DOI: 10.1134/s0006297911130116] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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50
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Tadagaki K, Jockers R, Kamal M. History and biological significance of GPCR heteromerization in the neuroendocrine system. Neuroendocrinology 2012; 95:223-31. [PMID: 22156565 DOI: 10.1159/000330000] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 06/07/2011] [Indexed: 12/18/2022]
Abstract
G protein-coupled receptors (GPCRs) constitute a large family of seven transmembrane proteins that regulate major cellular functions. The important role of GPCRs in the neuroendocrine system is outlined by the great interest of pharmaceutical companies in developing new drugs targeting these receptors. GPCRs exist as monomers, but can also be organized in oligomeric structures composed of either homo- or heteromers. GPCR heteromerization may play an important role in modulating and fine-tuning GPCR function and signaling. The literature reports many examples of GPCR heteromers in vitro raising the question of the physiological relevance of these complexes in tissues. Considerable efforts are currently being directed towards conclusive evidence for the existence of GPCRs heteromers in vivo, a crucial step for the validation of the concept of GPCR heteromerization and future drug development. The present review will give a brief history of GPCR oligomerization and emphasize the importance and physiological relevance of GPCR heteromerization by discussing key examples of GPCR couples.
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Affiliation(s)
- Kenjiro Tadagaki
- Inserm, U1016, Institut Cochin, CNRS UMR 8104, Université Paris Descartes, Paris, France
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