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Houghton FM, Adams SE, Ríos AS, Masino L, Purkiss AG, Briggs DC, Ledda F, McDonald NQ. Architecture and regulation of a GDNF-GFRα1 synaptic adhesion assembly. Nat Commun 2023; 14:7551. [PMID: 37985758 PMCID: PMC10661694 DOI: 10.1038/s41467-023-43148-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 11/01/2023] [Indexed: 11/22/2023] Open
Abstract
Glial-cell line derived neurotrophic factor (GDNF) bound to its co-receptor GFRα1 stimulates the RET receptor tyrosine kinase, promoting neuronal survival and neuroprotection. The GDNF-GFRα1 complex also supports synaptic cell adhesion independently of RET. Here, we describe the structure of a decameric GDNF-GFRα1 assembly determined by crystallography and electron microscopy, revealing two GFRα1 pentamers bridged by five GDNF dimers. We reconsitituted the assembly between adhering liposomes and used cryo-electron tomography to visualize how the complex fulfils its membrane adhesion function. The GFRα1:GFRα1 pentameric interface was further validated both in vitro by native PAGE and in cellulo by cell-clustering and dendritic spine assays. Finally, we provide biochemical and cell-based evidence that RET and heparan sulfate cooperate to prevent assembly of the adhesion complex by competing for the adhesion interface. Our results provide a mechanistic framework to understand GDNF-driven cell adhesion, its relationship to trophic signalling, and the central role played by GFRα1.
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Affiliation(s)
- F M Houghton
- Signalling and Structural Biology laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - S E Adams
- Signalling and Structural Biology laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
- Vertex Pharmaceuticals, 86-88 Jubilee Avenue, Milton Park, Abingdon, Oxfordshire, OX14 4RW, UK
| | - A S Ríos
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires, Av. Patricias Argentinas 435, C1405BWE, Buenos Aires, Argentina
| | - L Masino
- Structural Biology Science and Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - A G Purkiss
- Structural Biology Science and Technology Platform, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - D C Briggs
- Signalling and Structural Biology laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK
| | - F Ledda
- Fundación Instituto Leloir, Instituto de Investigaciones Bioquímicas de Buenos Aires, Av. Patricias Argentinas 435, C1405BWE, Buenos Aires, Argentina
| | - N Q McDonald
- Signalling and Structural Biology laboratory, The Francis Crick Institute, 1 Midland Road, London, NW1 1AT, UK.
- Institute of Structural and Molecular Biology, Department of Biological Sciences, Birkbeck College, Malet Street, London, WC1E 7HX, UK.
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Missense Variants in GFRA1 and NPNT Are Associated with Congenital Anomalies of the Kidney and Urinary Tract. Genes (Basel) 2022; 13:genes13101687. [PMID: 36292572 PMCID: PMC9601797 DOI: 10.3390/genes13101687] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 09/10/2022] [Accepted: 09/12/2022] [Indexed: 11/16/2022] Open
Abstract
The use of next-generation sequencing (NGS) has helped in identifying many genes that cause congenital anomalies of the kidney and urinary tract (CAKUT). Bilateral renal agenesis (BRA) is the most severe presentation of CAKUT, and its association with autosomal recessively inherited genes is expanding. Highly consanguineous populations can impact the detection of recessively inherited genes. Here, we report two families harboring homozygous missense variants in recently described genes, NPNT and GFRA1. Two consanguineous families with neonatal death due to CAKUT were investigated. Fetal ultrasound of probands identified BRA in the first family and severe renal cystic dysplasia in the second family. Exome sequencing coupled with homozygosity mapping was performed, and Sanger sequencing was used to confirm segregation of alleles in both families. In the first family with BRA, we identified a homozygous missense variant in GFRA1: c.362A>G; p.(Tyr121Cys), which is predicted to damage the protein structure. In the second family with renal cystic dysplasia, we identified a homozygous missense variant in NPNT: c.56C>G; p.(Ala19Gly), which is predicted to disrupt the signal peptide site. We report two Saudi Arabian consanguineous families with CAKUT phenotypes that included renal agenesis caused by missense variants in GFRA1 and NPNT, confirming the role of these two genes in human kidney development.
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Abstract
Single-pass transmembrane receptors (SPTMRs) represent a diverse group of integral membrane proteins that are involved in many essential cellular processes, including signal transduction, cell adhesion, and transmembrane transport of materials. Dysregulation of the SPTMRs is linked with many human diseases. Despite extensive efforts in past decades, the mechanisms of action of the SPTMRs remain incompletely understood. One major hurdle is the lack of structures of the full-length SPTMRs in different functional states. Such structural information is difficult to obtain by traditional structural biology methods such as X-ray crystallography and nuclear magnetic resonance (NMR). The recent rapid development of single-particle cryo-electron microscopy (cryo-EM) has led to an exponential surge in the number of high-resolution structures of integral membrane proteins, including SPTMRs. Cryo-EM structures of SPTMRs solved in the past few years have tremendously improved our understanding of how SPTMRs function. In this review, we will highlight these progresses in the structural studies of SPTMRs by single-particle cryo-EM, analyze important structural details of each protein involved, and discuss their implications on the underlying mechanisms. Finally, we also briefly discuss remaining challenges and exciting opportunities in the field.
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Affiliation(s)
- Kai Cai
- Departments of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas 75231, USA
| | - Xuewu Zhang
- Departments of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas 75231, USA
- Departments of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75231, USA
- Corresponding Author: Xuewu Zhang, Department of pharmacology, UT Southwestern Medical Center, Dallas, TX 75390, USA;
| | - Xiao-chen Bai
- Departments of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas 75231, USA
- Departments of Cell Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75231, USA
- Corresponding Author: Xiao-chen Bai, Department of Biophysics, UT Southwestern Medical Center, Dallas, TX 75390, USA;
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Unexpected structures formed by the kinase RET C634R mutant extracellular domain suggest potential oncogenic mechanisms in MEN2A. J Biol Chem 2022; 298:102380. [PMID: 35985422 PMCID: PMC9490035 DOI: 10.1016/j.jbc.2022.102380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 07/31/2022] [Accepted: 08/03/2022] [Indexed: 11/25/2022] Open
Abstract
The RET receptor tyrosine kinase plays a pivotal role in cell survival, proliferation, and differentiation, and its abnormal activation leads to cancers through receptor fusions or point mutations. Mutations that disrupt the disulfide network in the extracellular domain (ECD) of RET drive multiple endocrine neoplasia type 2A (MEN2A), a hereditary syndrome associated with the development of thyroid cancers. However, structural details of how specific mutations affect RET are unclear. Here, we present the first structural insights into the ECD of the RET(C634R) mutant, the most common mutation in MEN2A. Using electron microscopy, we demonstrate that the C634R mutation causes ligand-independent dimerization of the RET ECD, revealing an unusual tail-to-tail conformation that is distinct from the ligand-induced signaling dimer of WT RET. Additionally, we show that the RETC634R ECD dimer can form complexes with at least two of the canonical RET ligands and that these complexes form very different structures than WT RET ECD upon ligand binding. In conclusion, this structural analysis of cysteine-mutant RET ECD suggests a potential key mechanism of cancer induction in MEN2A, both in the absence and presence of its native ligands, and may offer new targets for therapeutic intervention.
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TAKAHASHI M. RET receptor signaling: Function in development, metabolic disease, and cancer. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2022; 98:112-125. [PMID: 35283407 PMCID: PMC8948417 DOI: 10.2183/pjab.98.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 01/11/2022] [Indexed: 06/14/2023]
Abstract
The RET proto-oncogene encodes a receptor tyrosine kinase whose alterations are responsible for various human cancers and developmental disorders, including thyroid cancer, non-small cell lung cancer, multiple endocrine neoplasia type 2, and Hirschsprung's disease. RET receptors are physiologically activated by glial cell line-derived neurotrophic factor (GDNF) family ligands that bind to the coreceptor GDNF family receptor α (GFRα). Signaling via the GDNF/GFRα1/RET ternary complex plays crucial roles in the development of the enteric nervous system, kidneys, and urinary tract, as well as in the self-renewal of spermatogonial stem cells. In addition, another ligand, growth differentiation factor-15 (GDF15), has been shown to bind to GFRα-like and activate RET, regulating body weight. GDF15 is a stress response cytokine, and its elevated serum levels affect metabolism and anorexia-cachexia syndrome. Moreover, recent development of RET-specific kinase inhibitors contributed significantly to progress in the treatment of patients with RET-altered cancer. This review focuses on the broad roles of RET in development, metabolic diseases, and cancer.
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Affiliation(s)
- Masahide TAKAHASHI
- International Center for Cell and Gene Therapy, Fujita Health University, Toyoake, Aichi, Japan
- Department of Pathology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
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