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Yee SW, Macdonald CB, Mitrovic D, Zhou X, Koleske ML, Yang J, Buitrago Silva D, Rockefeller Grimes P, Trinidad DD, More SS, Kachuri L, Witte JS, Delemotte L, Giacomini KM, Coyote-Maestas W. The full spectrum of SLC22 OCT1 mutations illuminates the bridge between drug transporter biophysics and pharmacogenomics. Mol Cell 2024; 84:1932-1947.e10. [PMID: 38703769 DOI: 10.1016/j.molcel.2024.04.008] [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: 07/11/2023] [Revised: 01/04/2024] [Accepted: 04/15/2024] [Indexed: 05/06/2024]
Abstract
Mutations in transporters can impact an individual's response to drugs and cause many diseases. Few variants in transporters have been evaluated for their functional impact. Here, we combine saturation mutagenesis and multi-phenotypic screening to dissect the impact of 11,213 missense single-amino-acid deletions, and synonymous variants across the 554 residues of OCT1, a key liver xenobiotic transporter. By quantifying in parallel expression and substrate uptake, we find that most variants exert their primary effect on protein abundance, a phenotype not commonly measured alongside function. Using our mutagenesis results combined with structure prediction and molecular dynamic simulations, we develop accurate structure-function models of the entire transport cycle, providing biophysical characterization of all known and possible human OCT1 polymorphisms. This work provides a complete functional map of OCT1 variants along with a framework for integrating functional genomics, biophysical modeling, and human genetics to predict variant effects on disease and drug efficacy.
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Affiliation(s)
- Sook Wah Yee
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Christian B Macdonald
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Darko Mitrovic
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, 12121 Solna, Stockholm, Stockholm County 114 28, Sweden
| | - Xujia Zhou
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Megan L Koleske
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jia Yang
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Dina Buitrago Silva
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Patrick Rockefeller Grimes
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Donovan D Trinidad
- Department of Medicine, Division of Infectious Disease, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Swati S More
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Linda Kachuri
- Department of Epidemiology and Population Health, Stanford University, Stanford, CA 94305, USA; Stanford Cancer Institute, Stanford University, Stanford, CA 94305, USA
| | - John S Witte
- Department of Epidemiology and Population Health, Stanford University, Stanford, CA 94305, USA; Stanford Cancer Institute, Stanford University, Stanford, CA 94305, USA
| | - Lucie Delemotte
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, 12121 Solna, Stockholm, Stockholm County 114 28, Sweden.
| | - Kathleen M Giacomini
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94143, USA.
| | - Willow Coyote-Maestas
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, CA 94143, USA; Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA 94143, USA; Chan Zuckerberg Biohub, San Francisco, CA 94148, USA.
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2
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Zeng YC, Sobti M, Quinn A, Smith NJ, Brown SHJ, Vandenberg JI, Ryan RM, O'Mara ML, Stewart AG. Structural basis of promiscuous substrate transport by Organic Cation Transporter 1. Nat Commun 2023; 14:6374. [PMID: 37821493 PMCID: PMC10567722 DOI: 10.1038/s41467-023-42086-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 09/29/2023] [Indexed: 10/13/2023] Open
Abstract
Organic Cation Transporter 1 (OCT1) plays a crucial role in hepatic metabolism by mediating the uptake of a range of metabolites and drugs. Genetic variations can alter the efficacy and safety of compounds transported by OCT1, such as those used for cardiovascular, oncological, and psychological indications. Despite its importance in drug pharmacokinetics, the substrate selectivity and underlying structural mechanisms of OCT1 remain poorly understood. Here, we present cryo-EM structures of full-length human OCT1 in the inward-open conformation, both ligand-free and drug-bound, indicating the basis for its broad substrate recognition. Comparison of our structures with those of outward-open OCTs provides molecular insight into the alternating access mechanism of OCTs. We observe that hydrophobic gates stabilize the inward-facing conformation, whereas charge neutralization in the binding pocket facilitates the release of cationic substrates. These findings provide a framework for understanding the structural basis of the promiscuity of drug binding and substrate translocation in OCT1.
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Affiliation(s)
- Yi C Zeng
- Molecular, Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.
- School of Clinical Medicine, Faculty of Medicine and Health, UNSW Sydney, Sydney, NSW, Australia.
| | - Meghna Sobti
- Molecular, Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
- School of Clinical Medicine, Faculty of Medicine and Health, UNSW Sydney, Sydney, NSW, Australia
| | - Ada Quinn
- Australian Institute of Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD, Australia
| | - Nicola J Smith
- School of Biomedical Sciences, Faculty of Medicine & Health, UNSW Sydney, Kensington, NSW, Australia
| | - Simon H J Brown
- School of Chemistry and Molecular Bioscience, Molecular Horizons, and Australian Research Council Centre for Cryo-electron Microscopy of Membrane Proteins, University of Wollongong, Wollongong, NSW, Australia
| | - Jamie I Vandenberg
- School of Clinical Medicine, Faculty of Medicine and Health, UNSW Sydney, Sydney, NSW, Australia
- Molecular Cardiology and Biophysics Division, The Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
| | - Renae M Ryan
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Megan L O'Mara
- Australian Institute of Bioengineering and Nanotechnology, University of Queensland, Brisbane, QLD, Australia
| | - Alastair G Stewart
- Molecular, Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia.
- School of Clinical Medicine, Faculty of Medicine and Health, UNSW Sydney, Sydney, NSW, Australia.
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3
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Meyer-Tönnies MJ, Tzvetkov MV. The end of the beginning in understanding SLC22 polyspecificity. Trends Pharmacol Sci 2023; 44:397-399. [PMID: 37117104 DOI: 10.1016/j.tips.2023.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 04/06/2023] [Accepted: 04/12/2023] [Indexed: 04/30/2023]
Abstract
SLC22 transporters involved in drug elimination and organ distribution are polyspecific. Now, the first cryo-EM structure of SLC22A3 (OCT3) is available from the Sitte and Korkhov groups. It paves the way for better understanding OCT3 function and for revealing the exact mechanisms conferring polyspecificity of the whole SLC22 family.
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Affiliation(s)
- Marleen Julia Meyer-Tönnies
- Department of General Pharmacology, Institute of Pharmacology, Center of Drug Absorption and Transport (C_DAT), University Medicine Greifswald, Greifswald, Germany
| | - Mladen Vassilev Tzvetkov
- Department of General Pharmacology, Institute of Pharmacology, Center of Drug Absorption and Transport (C_DAT), University Medicine Greifswald, Greifswald, Germany.
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4
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Suo Y, Wright NJ, Guterres H, Fedor JG, Butay KJ, Borgnia MJ, Im W, Lee SY. Molecular basis of polyspecific drug and xenobiotic recognition by OCT1 and OCT2. Nat Struct Mol Biol 2023; 30:1001-1011. [PMID: 37291422 PMCID: PMC10895701 DOI: 10.1038/s41594-023-01017-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 05/04/2023] [Indexed: 06/10/2023]
Abstract
A wide range of endogenous and xenobiotic organic ions require facilitated transport systems to cross the plasma membrane for their disposition. In mammals, organic cation transporter (OCT) subtypes 1 and 2 (OCT1 and OCT2, also known as SLC22A1 and SLC22A2, respectively) are polyspecific transporters responsible for the uptake and clearance of structurally diverse cationic compounds in the liver and kidneys, respectively. Notably, it is well established that human OCT1 and OCT2 play central roles in the pharmacokinetics and drug-drug interactions of many prescription medications, including metformin. Despite their importance, the basis of polyspecific cationic drug recognition and the alternating access mechanism for OCTs have remained a mystery. Here we present four cryo-electron microscopy structures of apo, substrate-bound and drug-bound OCT1 and OCT2 consensus variants, in outward-facing and outward-occluded states. Together with functional experiments, in silico docking and molecular dynamics simulations, these structures uncover general principles of organic cation recognition by OCTs and provide insights into extracellular gate occlusion. Our findings set the stage for a comprehensive structure-based understanding of OCT-mediated drug-drug interactions, which will prove critical in the preclinical evaluation of emerging therapeutics.
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Affiliation(s)
- Yang Suo
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Nicholas J Wright
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Hugo Guterres
- Departments of Biological Sciences, Chemistry, and Bioengineering, Lehigh University, Bethlehem, PA, USA
| | - Justin G Fedor
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA
| | - Kevin John Butay
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Mario J Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, Durham, NC, USA
| | - Wonpil Im
- Departments of Biological Sciences, Chemistry, and Bioengineering, Lehigh University, Bethlehem, PA, USA
| | - Seok-Yong Lee
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, USA.
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Yee SW, Macdonald C, Mitrovic D, Zhou X, Koleske ML, Yang J, Silva DB, Grimes PR, Trinidad D, More SS, Kachuri L, Witte JS, Delemotte L, Giacomini KM, Coyote-Maestas W. The full spectrum of OCT1 (SLC22A1) mutations bridges transporter biophysics to drug pharmacogenomics. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.06.543963. [PMID: 37333090 PMCID: PMC10274788 DOI: 10.1101/2023.06.06.543963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Membrane transporters play a fundamental role in the tissue distribution of endogenous compounds and xenobiotics and are major determinants of efficacy and side effects profiles. Polymorphisms within these drug transporters result in inter-individual variation in drug response, with some patients not responding to the recommended dosage of drug whereas others experience catastrophic side effects. For example, variants within the major hepatic Human organic cation transporter OCT1 (SLC22A1) can change endogenous organic cations and many prescription drug levels. To understand how variants mechanistically impact drug uptake, we systematically study how all known and possible single missense and single amino acid deletion variants impact expression and substrate uptake of OCT1. We find that human variants primarily disrupt function via folding rather than substrate uptake. Our study revealed that the major determinants of folding reside in the first 300 amino acids, including the first 6 transmembrane domains and the extracellular domain (ECD) with a stabilizing and highly conserved stabilizing helical motif making key interactions between the ECD and transmembrane domains. Using the functional data combined with computational approaches, we determine and validate a structure-function model of OCT1s conformational ensemble without experimental structures. Using this model and molecular dynamic simulations of key mutants, we determine biophysical mechanisms for how specific human variants alter transport phenotypes. We identify differences in frequencies of reduced function alleles across populations with East Asians vs European populations having the lowest and highest frequency of reduced function variants, respectively. Mining human population databases reveals that reduced function alleles of OCT1 identified in this study associate significantly with high LDL cholesterol levels. Our general approach broadly applied could transform the landscape of precision medicine by producing a mechanistic basis for understanding the effects of human mutations on disease and drug response.
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Affiliation(s)
- Sook Wah Yee
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States
| | - Christian Macdonald
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States
| | - Darko Mitrovic
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, 12121 Solna, Sweden
| | - Xujia Zhou
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States
| | - Megan L Koleske
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States
| | - Jia Yang
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States
| | - Dina Buitrago Silva
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States
| | - Patrick Rockefeller Grimes
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States
| | - Donovan Trinidad
- Department of Medicine, Division of Infectious Disease, University of California, San Francisco, United States
| | - Swati S More
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States
- Current address: Center for Drug Design (CDD), College of Pharmacy, University of Minnesota, Minnesota, United States
| | - Linda Kachuri
- Epidemiology and Population Health, Stanford University, California, United States
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, United States
| | - John S Witte
- Epidemiology and Population Health, Stanford University, California, United States
- Department of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, United States
| | - Lucie Delemotte
- Science for Life Laboratory, Department of Applied Physics, KTH Royal Institute of Technology, 12121 Solna, Sweden
| | - Kathleen M Giacomini
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States
| | - Willow Coyote-Maestas
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States
- Quantitative Biosciences Institute, University of California, San Francisco, United States
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6
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Suo Y, Wright NJ, Guterres H, Fedor JG, Butay KJ, Borgnia MJ, Im W, Lee SY. Molecular basis of polyspecific drug binding and transport by OCT1 and OCT2. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.15.532610. [PMID: 36993738 PMCID: PMC10055046 DOI: 10.1101/2023.03.15.532610] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
A wide range of endogenous and xenobiotic organic ions require facilitated transport systems to cross the plasma membrane for their disposition 1, 2 . In mammals, organic cation transporter subtypes 1 and 2 (OCT1 and OCT2, also known as SLC22A1 and SLC22A2, respectively) are polyspecific transporters responsible for the uptake and clearance of structurally diverse cationic compounds in the liver and kidneys, respectively 3, 4 . Notably, it is well established that human OCT1 and OCT2 play central roles in the pharmacokinetics, pharmacodynamics, and drug-drug interactions (DDI) of many prescription medications, including metformin 5, 6 . Despite their importance, the basis of polyspecific cationic drug recognition and the alternating access mechanism for OCTs have remained a mystery. Here, we present four cryo-EM structures of apo, substrate-bound, and drug-bound OCT1 and OCT2 in outward-facing and outward-occluded states. Together with functional experiments, in silico docking, and molecular dynamics simulations, these structures uncover general principles of organic cation recognition by OCTs and illuminate unexpected features of the OCT alternating access mechanism. Our findings set the stage for a comprehensive structure-based understanding of OCT-mediated DDI, which will prove critical in the preclinical evaluation of emerging therapeutics.
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Affiliation(s)
- Yang Suo
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina, 27710, USA
| | - Nicholas J. Wright
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina, 27710, USA
| | - Hugo Guterres
- Departments of Biological Sciences, Chemistry, and Bioengineering, Lehigh University, Bethlehem, Pennsylvania, 18015, USA
| | - Justin G. Fedor
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina, 27710, USA
| | - Kevin John Butay
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Mario J. Borgnia
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Wonpil Im
- Departments of Biological Sciences, Chemistry, and Bioengineering, Lehigh University, Bethlehem, Pennsylvania, 18015, USA
| | - Seok-Yong Lee
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina, 27710, USA
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7
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Cloning and Functional Characterization of Dog OCT1 and OCT2: Another Step in Exploring Species Differences in Organic Cation Transporters. Int J Mol Sci 2022; 23:ijms23095100. [PMID: 35563491 PMCID: PMC9102066 DOI: 10.3390/ijms23095100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/28/2022] [Accepted: 04/30/2022] [Indexed: 12/21/2022] Open
Abstract
OCT1 and OCT2 are polyspecific membrane transporters that are involved in hepatic and renal drug clearance in humans and mice. In this study, we cloned dog OCT1 and OCT2 and compared their function to the human and mouse orthologs. We used liver and kidney RNA to clone dog OCT1 and OCT2. The cloned and the publicly available RNA-Seq sequences differed from the annotated exon-intron structure of OCT1 in the dog genome CanFam3.1. An additional exon between exons 2 and 3 was identified and confirmed by sequencing in six additional dog breeds. Next, dog OCT1 and OCT2 were stably overexpressed in HEK293 cells and the transport kinetics of five drugs were analyzed. We observed strong differences in the transport kinetics between dog and human orthologs. Dog OCT1 transported fenoterol with 12.9-fold higher capacity but 14.3-fold lower affinity (higher KM) than human OCT1. Human OCT1 transported ipratropium with 5.2-fold higher capacity but 8.4-fold lower affinity than dog OCT1. Compared to human OCT2, dog OCT2 showed 10-fold lower transport of fenoterol and butylscopolamine. In conclusion, the functional characterization of dog OCT1 and OCT2 reported here may have implications when using dogs as pre-clinical models as well as for drug therapy in dogs.
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