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Howard MK, Hoppe N, Huang XP, Macdonald CB, Mehrota E, Grimes PR, Zahm A, Trinidad DD, English J, Coyote-Maestas W, Manglik A. Molecular basis of proton-sensing by G protein-coupled receptors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.17.590000. [PMID: 38659943 PMCID: PMC11042331 DOI: 10.1101/2024.04.17.590000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Three proton-sensing G protein-coupled receptors (GPCRs), GPR4, GPR65, and GPR68, respond to changes in extracellular pH to regulate diverse physiology and are implicated in a wide range of diseases. A central challenge in determining how protons activate these receptors is identifying the set of residues that bind protons. Here, we determine structures of each receptor to understand the spatial arrangement of putative proton sensing residues in the active state. With a newly developed deep mutational scanning approach, we determined the functional importance of every residue in proton activation for GPR68 by generating ~9,500 mutants and measuring effects on signaling and surface expression. This unbiased screen revealed that, unlike other proton-sensitive cell surface channels and receptors, no single site is critical for proton recognition in GPR68. Instead, a network of titratable residues extend from the extracellular surface to the transmembrane region and converge on canonical class A GPCR activation motifs to activate proton-sensing GPCRs. More broadly, our approach integrating structure and unbiased functional interrogation defines a new framework for understanding the rich complexity of GPCR signaling.
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Affiliation(s)
- Matthew K. Howard
- Tetrad graduate program, University of California, San Francisco, CA, USA
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
- Department of Bioengineering and Therapeutic Science, University of California, San Francisco, CA, USA
| | - Nicholas Hoppe
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
- Biophysics graduate program, University of California, San Francisco, CA, USA
| | - Xi-Ping Huang
- Department of Pharmacology and the National Institute of Mental Health Psychoactive Drug Screening Program (NIMH PDSP), The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Christian B. Macdonald
- Department of Bioengineering and Therapeutic Science, University of California, San Francisco, CA, USA
| | - Eshan Mehrota
- Tetrad graduate program, University of California, San Francisco, CA, USA
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
- Medical Scientist Training Program, University of California, San Francisco, CA, USA
| | | | - Adam Zahm
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Donovan D. Trinidad
- Department of Medicine, Division of Infectious Disease, University of California, San Francisco, United States
| | - Justin English
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Willow Coyote-Maestas
- Department of Bioengineering and Therapeutic Science, University of California, San Francisco, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
- Quantitative Biosciences Institute, University of California, San Francisco, USA
| | - Aashish Manglik
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA, USA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
- Quantitative Biosciences Institute, University of California, San Francisco, USA
- Department of Anesthesia and Perioperative Care, University of California, San Francisco, CA, USA
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Choquet H, Duot M, Herrera VA, Shrestha SK, Meyers TJ, Hoffmann TJ, Sangani PK, Lachke SA. Multi-tissue transcriptome-wide association study identifies novel candidate susceptibility genes for cataract. FRONTIERS IN OPHTHALMOLOGY 2024; 4:1362350. [PMID: 38984127 PMCID: PMC11182099 DOI: 10.3389/fopht.2024.1362350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 04/01/2024] [Indexed: 07/11/2024]
Abstract
Introduction Cataract is the leading cause of blindness among the elderly worldwide. Twin and family studies support an important role for genetic factors in cataract susceptibility with heritability estimates up to 58%. To date, 55 loci for cataract have been identified by genome-wide association studies (GWAS), however, much work remains to identify the causal genes. Here, we conducted a transcriptome-wide association study (TWAS) of cataract to prioritize causal genes and identify novel ones, and examine the impact of their expression. Methods We performed tissue-specific and multi-tissue TWAS analyses to assess associations between imputed gene expression from 54 tissues (including 49 from the Genotype Tissue Expression (GTEx) Project v8) with cataract using FUSION software. Meta-analyzed GWAS summary statistics from 59,944 cataract cases and 478,571 controls, all of European ancestry and from two cohorts (GERA and UK Biobank) were used. We then examined the expression of the novel genes in the lens tissue using the iSyTE database. Results Across tissue-specific and multi-tissue analyses, we identified 99 genes for which genetically predicted gene expression was associated with cataract after correcting for multiple testing. Of these 99 genes, 20 (AC007773.1, ANKH, ASIP, ATP13A2, CAPZB, CEP95, COQ6, CREB1, CROCC, DDX5, EFEMP1, EIF2S2, ESRRB, GOSR2, HERC4, INSRR, NIPSNAP2, PICALM, SENP3, and SH3YL1) did not overlap with previously reported cataract-associated loci. Tissue-specific analysis identified 202 significant gene-tissue associations for cataract, of which 166 (82.2%), representing 9 unique genes, were attributed to the previously reported 11q13.3 locus. Tissue-enrichment analysis revealed that gastrointestinal tissues represented one of the highest proportions of the Bonferroni-significant gene-tissue associations (21.3%). Moreover, this gastrointestinal tissue type was the only anatomical category significantly enriched in our results, after correcting for the number of tissue donors and imputable genes for each reference panel. Finally, most of the novel cataract genes (e.g., Capzb) were robustly expressed in iSyTE lens data. Discussion Our results provide evidence of the utility of imputation-based TWAS approaches to characterize known GWAS risk loci and identify novel candidate genes that may increase our understanding of cataract etiology. Our findings also highlight the fact that expression of genes associated with cataract susceptibility is not necessarily restricted to lens tissue.
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Affiliation(s)
- Hélène Choquet
- Kaiser Permanente Northern California (KPNC), Division of Research, Oakland, CA, United States
| | - Matthieu Duot
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
- The National Centre for Scientific Research (CNRS), IGDR (Institut de Génétique et Développement de Rennes) - Joint Research Units (UMR), Univ Rennes, Rennes, France
| | - Victor A Herrera
- Kaiser Permanente Northern California (KPNC), Division of Research, Oakland, CA, United States
| | - Sanjaya K Shrestha
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
| | - Travis J Meyers
- Kaiser Permanente Northern California (KPNC), Division of Research, Oakland, CA, United States
| | - Thomas J Hoffmann
- Institute for Human Genetics, University of California San Francisco (UCSF), San Francisco, CA, United States
- Department of Epidemiology and Biostatistics, UCSF, San Francisco, CA, United States
| | - Poorab K Sangani
- Department of Ophthalmology, KPNC, South San Francisco, CA, United States
| | - Salil A Lachke
- Department of Biological Sciences, University of Delaware, Newark, DE, United States
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, United States
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Brazier F, Cornière N, Picard N, Chambrey R, Eladari D. Pendrin: linking acid base to blood pressure. Pflugers Arch 2024; 476:533-543. [PMID: 38110744 DOI: 10.1007/s00424-023-02897-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/11/2023] [Accepted: 12/11/2023] [Indexed: 12/20/2023]
Abstract
Pendrin (SLC26A4) is an anion exchanger from the SLC26 transporter family which is mutated in human patients affected by Pendred syndrome, an autosomal recessive disease characterized by sensoneurinal deafness and hypothyroidism. Pendrin is also expressed in the kidney where it mediates the exchange of internal HCO3- for external Cl- at the apical surface of renal type B and non-A non-B-intercalated cells. Studies using pendrin knockout mice have first revealed that pendrin is essential for renal base excretion. However, subsequent studies have demonstrated that pendrin also controls chloride absorption by the distal nephron and that this mechanism is critical for renal NaCl balance. Furthermore, pendrin has been shown to control vascular volume and ultimately blood pressure. This review summarizes the current knowledge about how pendrin is linking renal acid-base regulation to blood pressure control.
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Affiliation(s)
- François Brazier
- Centre de dépistage et de Médecine de précision des Maladies Rénales, Service de Néphrologie, Centre Hospitalier Universitaire Amiens-Picardie, Université de Picardie Jules Verne, F-80000, Amiens, France
| | - Nicolas Cornière
- Centre de dépistage et de Médecine de précision des Maladies Rénales, Service de Néphrologie, Centre Hospitalier Universitaire Amiens-Picardie, Université de Picardie Jules Verne, F-80000, Amiens, France
| | - Nicolas Picard
- Laboratory of Tissue Biology and Therapeutic Engineering, UMR 5305 CNRS, University Lyon 1, Lyon, France
| | - Régine Chambrey
- Paris Cardiovascular Research Center (PARCC), INSERM U970, F-75015, Paris, France
| | - Dominique Eladari
- Centre de dépistage et de Médecine de précision des Maladies Rénales, Service de Néphrologie, Centre Hospitalier Universitaire Amiens-Picardie, Université de Picardie Jules Verne, F-80000, Amiens, France.
- Laboratory of Tissue Biology and Therapeutic Engineering, UMR 5305 CNRS, University Lyon 1, Lyon, France.
- French Clinical Research Infrastructure Network (F-CRIN): INI-CRCT, Vandœuvre-lès-Nancy, France.
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An W, Hall C, Li J, Hung A, Wu J, Park J, Wang L, Bai XC, Choi E. Activation of the insulin receptor by insulin-like growth factor 2. Nat Commun 2024; 15:2609. [PMID: 38521788 PMCID: PMC10960814 DOI: 10.1038/s41467-024-46990-6] [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: 01/09/2024] [Accepted: 03/15/2024] [Indexed: 03/25/2024] Open
Abstract
Insulin receptor (IR) controls growth and metabolism. Insulin-like growth factor 2 (IGF2) has different binding properties on two IR isoforms, mimicking insulin's function. However, the molecular mechanism underlying IGF2-induced IR activation remains unclear. Here, we present cryo-EM structures of full-length human long isoform IR (IR-B) in both the inactive and IGF2-bound active states, and short isoform IR (IR-A) in the IGF2-bound active state. Under saturated IGF2 concentrations, both the IR-A and IR-B adopt predominantly asymmetric conformations with two or three IGF2s bound at site-1 and site-2, which differs from that insulin saturated IR forms an exclusively T-shaped symmetric conformation. IGF2 exhibits a relatively weak binding to IR site-2 compared to insulin, making it less potent in promoting full IR activation. Cell-based experiments validated the functional importance of IGF2 binding to two distinct binding sites in optimal IR signaling and trafficking. In the inactive state, the C-terminus of α-CT of IR-B contacts FnIII-2 domain of the same protomer, hindering its threading into the C-loop of IGF2, thus reducing the association rate of IGF2 with IR-B. Collectively, our studies demonstrate the activation mechanism of IR by IGF2 and reveal the molecular basis underlying the different affinity of IGF2 to IR-A and IR-B.
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Affiliation(s)
- Weidong An
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Catherine Hall
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
| | - Jie Li
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Albert Hung
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
| | - Jiayi Wu
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
| | - Junhee Park
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA
| | - Liwei Wang
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Xiao-Chen Bai
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
| | - Eunhee Choi
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, 10032, USA.
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Abstract
Cancers undergo sequential changes to proton (H+) concentration and sensing that are consequences of the disease and facilitate its further progression. The impact of protonation state on protein activity can arise from alterations to amino acids or their titration. Indeed, many cancer-initiating mutations influence pH balance, regulation or sensing in a manner that enables growth and invasion outside normal constraints as part of oncogenic transformation. These cancer-supporting effects become more prominent when tumours develop an acidic microenvironment owing to metabolic reprogramming and disordered perfusion. The ensuing intracellular and extracellular pH disturbances affect multiple aspects of tumour biology, ranging from proliferation to immune surveillance, and can even facilitate further mutagenesis. As a selection pressure, extracellular acidosis accelerates disease progression by favouring acid-resistant cancer cells, which are typically associated with aggressive phenotypes. Although acid-base disturbances in tumours often occur alongside hypoxia and lactate accumulation, there is now ample evidence for a distinct role of H+-operated responses in key events underpinning cancer. The breadth of these actions presents therapeutic opportunities to change the trajectory of disease.
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Affiliation(s)
- Pawel Swietach
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
| | - Ebbe Boedtkjer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.
| | - Stine Falsig Pedersen
- Department of Biology, University of Copenhagen, University of Copenhagen, Faculty of Science, København, Denmark.
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