1
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Wang N, Waghray D, Caveney NA, Jude KM, Garcia KC. Structural insights into human MHC-II association with invariant chain. Proc Natl Acad Sci U S A 2024; 121:e2403031121. [PMID: 38687785 PMCID: PMC11087810 DOI: 10.1073/pnas.2403031121] [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: 02/13/2024] [Accepted: 03/29/2024] [Indexed: 05/02/2024] Open
Abstract
The loading of processed peptides on to major histocompatibility complex II (MHC-II) molecules for recognition by T cells is vital to cell-mediated adaptive immunity. As part of this process, MHC-II associates with the invariant chain (Ii) during biosynthesis in the endoplasmic reticulum to prevent premature peptide loading and to serve as a scaffold for subsequent proteolytic processing into MHC-II-CLIP. Cryo-electron microscopy structures of full-length Human Leukocyte Antigen-DR (HLA-DR) and HLA-DQ complexes associated with Ii, resolved at 3.0 to 3.1 Å, elucidate the trimeric assembly of the HLA/Ii complex and define atomic-level interactions between HLA, Ii transmembrane domains, loop domains, and class II-associated invariant chain peptides (CLIP). Together with previous structures of MHC-II peptide loading intermediates DO and DM, our findings complete the structural path governing class II antigen presentation.
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Affiliation(s)
- Nan Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA94305
- HHMI, Stanford University School of Medicine, Stanford, CA94305
| | - Deepa Waghray
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA94305
| | - Nathanael A. Caveney
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA94305
| | - Kevin M. Jude
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA94305
- HHMI, Stanford University School of Medicine, Stanford, CA94305
| | - K. Christopher Garcia
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA94305
- HHMI, Stanford University School of Medicine, Stanford, CA94305
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA94305
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2
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Toth M, Reithofer M, Dutra G, Pereira Aguilar P, Dürauer A, Grabherr R. Comprehensive Comparison of Baculoviral and Plasmid Gene Delivery in Mammalian Cells. Viruses 2024; 16:426. [PMID: 38543791 PMCID: PMC10974095 DOI: 10.3390/v16030426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/08/2024] [Accepted: 03/08/2024] [Indexed: 05/23/2024] Open
Abstract
(1) Recombinant protein production in mammalian cells is either based on transient transfection processes, often inefficient and underlying high batch-to-batch variability, or on laborious generation of stable cell lines. Alternatively, BacMam, a transduction process using the baculovirus, can be employed. (2) Six transfecting agents were compared to baculovirus transduction in terms of transient and stable protein expression characteristics of the model protein ACE2-eGFP using HEK293-6E, CHO-K1, and Vero cell lines. Furthermore, process optimization such as expression enhancement using sodium butyrate and TSA or baculovirus purification was assessed. (3) Baculovirus transduction efficiency was superior to all transfection agents for all cell lines. Transduced protein expression was moderate, but an 18-fold expression increase was achieved using the enhancer sodium butyrate. Ultracentrifugation of baculovirus from a 3.5 L bioreactor significantly improved the transduction efficiency and protein expression. Stable cell lines were obtained with each baculovirus transduction, yet stable cell line generation after transfection was highly unreliable. (4) This study demonstrated the superiority of the BacMam platform to standard transfections. The baculovirus efficiently transduced an array of cell lines both transiently and stably and achieved the highest efficiency for all tested cell lines. The feasibility of the scale-up of baculovirus production was demonstrated and the possibility of baculovirus purification was successfully explored.
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Affiliation(s)
- Maria Toth
- Department of Biotechnology, University of Natural Resources and Life Sciences Vienna, 1190 Vienna, AT, Austria
| | - Manuel Reithofer
- Department of Biotechnology, University of Natural Resources and Life Sciences Vienna, 1190 Vienna, AT, Austria
| | - Gregory Dutra
- Austrian Centre of Industrial Biotechnology (ACIB), 1190 Vienna, AT, Austria
| | | | - Astrid Dürauer
- Department of Biotechnology, University of Natural Resources and Life Sciences Vienna, 1190 Vienna, AT, Austria
| | - Reingard Grabherr
- Department of Biotechnology, University of Natural Resources and Life Sciences Vienna, 1190 Vienna, AT, Austria
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3
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Li J, Canham SM, Wu H, Henault M, Chen L, Liu G, Chen Y, Yu G, Miller HR, Hornak V, Brittain SM, Michaud GA, Tutter A, Broom W, Digan ME, McWhirter SM, Sivick KE, Pham HT, Chen CH, Tria GS, McKenna JM, Schirle M, Mao X, Nicholson TB, Wang Y, Jenkins JL, Jain RK, Tallarico JA, Patel SJ, Zheng L, Ross NT, Cho CY, Zhang X, Bai XC, Feng Y. Activation of human STING by a molecular glue-like compound. Nat Chem Biol 2024; 20:365-372. [PMID: 37828400 PMCID: PMC10907298 DOI: 10.1038/s41589-023-01434-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 09/02/2023] [Indexed: 10/14/2023]
Abstract
Stimulator of interferon genes (STING) is a dimeric transmembrane adapter protein that plays a key role in the human innate immune response to infection and has been therapeutically exploited for its antitumor activity. The activation of STING requires its high-order oligomerization, which could be induced by binding of the endogenous ligand, cGAMP, to the cytosolic ligand-binding domain. Here we report the discovery through functional screens of a class of compounds, named NVS-STGs, that activate human STING. Our cryo-EM structures show that NVS-STG2 induces the high-order oligomerization of human STING by binding to a pocket between the transmembrane domains of the neighboring STING dimers, effectively acting as a molecular glue. Our functional assays showed that NVS-STG2 could elicit potent STING-mediated immune responses in cells and antitumor activities in animal models.
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Affiliation(s)
- Jie Li
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Stephen M Canham
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA.
| | - Hua Wu
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Martin Henault
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Lihao Chen
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Guoxun Liu
- Novartis Institutes for BioMedical Research, San Diego, CA, USA
| | - Yu Chen
- Novartis Institutes for BioMedical Research, San Diego, CA, USA
| | - Gary Yu
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Howard R Miller
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Viktor Hornak
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | | | | | - Antonin Tutter
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Wendy Broom
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | | | | | | | - Helen T Pham
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | | | - George S Tria
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | | | - Markus Schirle
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Xiaohong Mao
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | | | - Yuan Wang
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | | | - Rishi K Jain
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | | | - Sejal J Patel
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Lianxing Zheng
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Nathan T Ross
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA
| | - Charles Y Cho
- Novartis Institutes for BioMedical Research, San Diego, CA, USA
| | - Xuewu Zhang
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Xiao-Chen Bai
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Yan Feng
- Novartis Institutes for BioMedical Research, Cambridge, MA, USA.
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4
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Madapally HV, Abe K, Dubey V, Khandelia H. Specific protonation of acidic residues confers K + selectivity to the gastric proton pump. J Biol Chem 2024; 300:105542. [PMID: 38072058 PMCID: PMC10825007 DOI: 10.1016/j.jbc.2023.105542] [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: 10/22/2023] [Revised: 11/20/2023] [Accepted: 11/29/2023] [Indexed: 01/11/2024] Open
Abstract
The gastric proton pump (H+,K+-ATPase) transports a proton into the stomach lumen for every K+ ion exchanged in the opposite direction. In the lumen-facing state of the pump (E2), the pump selectively binds K+ despite the presence of a 10-fold higher concentration of Na+. The molecular basis for the ion selectivity of the pump is unknown. Using molecular dynamics simulations, free energy calculations, and Na+ and K+-dependent ATPase activity assays, we demonstrate that the K+ selectivity of the pump depends upon the simultaneous protonation of the acidic residues E343 and E795 in the ion-binding site. We also show that when E936 is protonated, the pump becomes Na+ sensitive. The protonation-mimetic mutant E936Q exhibits weak Na+-activated ATPase activity. A 2.5-Å resolution cryo-EM structure of the E936Q mutant in the K+-occluded E2-Pi form shows, however, no significant structural difference compared with wildtype except less-than-ideal coordination of K+ in the mutant. The selectivity toward a specific ion correlates with a more rigid and less fluctuating ion-binding site. Despite being exposed to a pH of 1, the fundamental principle driving the K+ ion selectivity of H+,K+-ATPase is similar to that of Na+,K+-ATPase: the ionization states of the acidic residues in the ion-binding sites determine ion selectivity. Unlike the Na+,K+-ATPase, however, protonation of an ion-binding glutamate residue (E936) confers Na+ sensitivity.
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Affiliation(s)
- Hridya Valia Madapally
- PHYLIFE, Physical Life Science, Department of Physics Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - Kazuhiro Abe
- Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan; Cellular and Structural Physiology Institute, Nagoya University, Nagoya, Japan
| | - Vikas Dubey
- PHYLIFE, Physical Life Science, Department of Physics Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark
| | - Himanshu Khandelia
- PHYLIFE, Physical Life Science, Department of Physics Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark.
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5
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Puente-Massaguer E, Gòdia F. Recombinant Protein Production in Suspension Mammalian Cells Using the BacMam Baculovirus Expression System. Methods Mol Biol 2024; 2829:329-339. [PMID: 38951347 DOI: 10.1007/978-1-0716-3961-0_25] [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] [Indexed: 07/03/2024]
Abstract
Mammalian cell lines are one of the best options when it comes to the production of complex proteins requiring specific glycosylation patterns. Plasmid DNA transfection and stable cell lines are frequently used for recombinant protein production, but they are expensive at large scale or can become time-consuming, respectively. The BacMam baculovirus (BV) is a safe and cost-effective platform to produce recombinant proteins in mammalian cells. The process of generating BacMam BVs is straightforward and similar to the generation of "insect" BVs, with different commercially available platforms. Although there are several protocols that describe recombinant protein expression with the BacMam BV in adherent cell lines, limited information is available on suspension cells. Therefore, it is of relevance to define the conditions to produce recombinant proteins in suspension cell cultures with BacMam BVs that facilitate bioprocess transfer to larger volumes. Here, we describe a method to generate a high titer BacMam BV stock and produce recombinant proteins in suspension HEK293 cells.
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Affiliation(s)
- Eduard Puente-Massaguer
- Department of Chemical, Biological and Environmental Engineering, Universitat Autònoma de Barcelona, Barcelona, Spain.
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Francesc Gòdia
- Department of Chemical, Biological and Environmental Engineering, Universitat Autònoma de Barcelona, Barcelona, Spain
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6
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Flock J, Xie Y, Lemaitre R, Lapouge K, Remans K. The Use of Baculovirus-Mediated Gene Expression in Mammalian Cells for Recombinant Protein Production. Methods Mol Biol 2024; 2810:29-53. [PMID: 38926271 DOI: 10.1007/978-1-0716-3878-1_3] [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] [Indexed: 06/28/2024]
Abstract
Baculovirus-mediated gene expression in mammalian cells, BacMam, is a useful alternative to transient transfection for recombinant protein production in various types of mammalian cell lines. We decided to establish BacMam in our lab in order to streamline our workflows for gene expression in insect and mammalian cells, as it is straightforward to parallelize the baculovirus generation for both types of eukaryotic cells. This chapter provides a step-by-step description of the protocols we use for the generation of the recombinant BacMam viruses, the transduction of mammalian cell cultures, and optimization of the protein production conditions through small-scale expression and purification tests.
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Affiliation(s)
- Julia Flock
- Protein Expression and Purification Core Facility, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Yexin Xie
- Protein Expression and Purification Core Facility, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Régis Lemaitre
- Protein Biochemistry Facility, Max Planck Institute of Molecular Cell Biology and Genetics (MPI-CBG), Dresden, Germany
| | - Karine Lapouge
- Protein Expression and Purification Core Facility, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Kim Remans
- Protein Expression and Purification Core Facility, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany.
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7
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Artigas P, Meyer DJ, Young VC, Spontarelli K, Eastman J, Strandquist E, Rui H, Roux B, Birk MA, Nakanishi H, Abe K, Gatto C. A Na pump with reduced stoichiometry is up-regulated by brine shrimp in extreme salinities. Proc Natl Acad Sci U S A 2023; 120:e2313999120. [PMID: 38079564 PMCID: PMC10756188 DOI: 10.1073/pnas.2313999120] [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: 08/14/2023] [Accepted: 10/27/2023] [Indexed: 12/18/2023] Open
Abstract
Brine shrimp (Artemia) are the only animals to thrive at sodium concentrations above 4 M. Salt excretion is powered by the Na+,K+-ATPase (NKA), a heterodimeric (αβ) pump that usually exports 3Na+ in exchange for 2 K+ per hydrolyzed ATP. Artemia express several NKA catalytic α-subunit subtypes. High-salinity adaptation increases abundance of α2KK, an isoform that contains two lysines (Lys308 and Lys758 in transmembrane segments TM4 and TM5, respectively) at positions where canonical NKAs have asparagines (Xenopus α1's Asn333 and Asn785). Using de novo transcriptome assembly and qPCR, we found that Artemia express two salinity-independent canonical α subunits (α1NN and α3NN), as well as two β variants, in addition to the salinity-controlled α2KK. These β subunits permitted heterologous expression of the α2KK pump and determination of its CryoEM structure in a closed, ion-free conformation, showing Lys758 residing within the ion-binding cavity. We used electrophysiology to characterize the function of α2KK pumps and compared it to that of Xenopus α1 (and its α2KK-mimicking single- and double-lysine substitutions). The double substitution N333K/N785K confers α2KK-like characteristics to Xenopus α1, and mutant cycle analysis reveals energetic coupling between these two residues, illustrating how α2KK's Lys308 helps to maintain high affinity for external K+ when Lys758 occupies an ion-binding site. By measuring uptake under voltage clamp of the K+-congener 86Rb+, we prove that double-lysine-substituted pumps transport 2Na+ and 1 K+ per catalytic cycle. Our results show how the two lysines contribute to generate a pump with reduced stoichiometry allowing Artemia to maintain steeper Na+ gradients in hypersaline environments.
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Affiliation(s)
- Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX79430
| | - Dylan J. Meyer
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX79430
| | - Victoria C. Young
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX79430
| | - Kerri Spontarelli
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX79430
| | - Jessica Eastman
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX79430
| | - Evan Strandquist
- School of Biological Sciences, Illinois State University, Normal, IL61790
| | - Huan Rui
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL60637
| | - Benoît Roux
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL60637
| | - Matthew A. Birk
- Department of Biology, Saint Francis University, Loretto, PA15940
| | - Hanayo Nakanishi
- Department of Basic Medical Sciences, Cellular and Structural Physiology Institute, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya464-8601, Japan
| | - Kazuhiro Abe
- Department of Basic Medical Sciences, Cellular and Structural Physiology Institute, Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya464-8601, Japan
| | - Craig Gatto
- School of Biological Sciences, Illinois State University, Normal, IL61790
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8
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Abe K, Nishizawa T, Artigas P. An unusual conformation from Na +-sensitive non-gastric proton pump mutants reveals molecular mechanisms of cooperative Na +-binding. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119543. [PMID: 37482134 DOI: 10.1016/j.bbamcr.2023.119543] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/29/2023] [Accepted: 07/14/2023] [Indexed: 07/25/2023]
Abstract
The Na+,K+-ATPase (NKA) and non-gastric H+,K+- ATPase (ngHKA) share ~65 % sequence identity, and nearly identical catalytic cycles. These pumps alternate between inward-facing (E1) and outward-facing (E2) conformations and differ in their exported substrate (Na+ or H+) and stoichiometries (3 Na+:2 K+ or 1 H+:1 K+). We reported that structures of the NKA-mimetic ngHKA mutant K794S/A797P/W940/R949C (SPWC) with 2 K+ occluded in E2-Pi and 3 Na+-bound in E1·ATP states were nearly identical to NKA structures in equivalent states. Here we report the cryo-EM structures of K794A and K794S, two poorly-selective ngHKA mutants, under conditions to stabilize the E1·ATP state. Unexpectedly, the structures show a hybrid with both E1- and E2-like structural features. While transmembrane segments TM1-TM3 and TM4's extracellular half adopted an E2-like conformation, the rest of the protein assumed an E1 configuration. Two spherical densities, likely bound Na+, were observed at cation-binding sites I and III, without density at site II. This explains the E2-like conformation of TM4's exoplasmic half. In NKA, oxygen atoms derived from the unwound portion of TM4 coordinated Na+ at site II. Thus, the lack of Na+ at site II of K794A/S prevents the luminal portion of TM4 from taking an E1-like position. The K794A structure also suggests that incomplete coordination of Na+ at site III induces the halfway rotation of TM6, which impairs Na+-binding at the site II. Thus, our observations provide insight into the molecular mechanism of E2-E1 transition and cooperative Na+-binding in the NKA and other related cation pumps.
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Affiliation(s)
- Kazuhiro Abe
- Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya 464-8601, Japan; Cellular and Structural Physiology Institute, Nagoya University, Nagoya 464-8601, Japan; Center for One Medicine Innovative Translational Research, Gifu University Institute for Advanced Study, Japan.
| | - Tomohiro Nishizawa
- Graduate School of Medical Life Sciences, Yokohama City University, Tsurumi, Yokohama 230-0045, Japan
| | - Pablo Artigas
- Department of Cell Physiology and Molecular Biophysics, Center for Membrane Protein Research, Texas Tech University Health Sciences Center, Lubbock, TX, USA
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9
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Eltokhi A, Catterall WA, Gamal El-Din TM. Cell-cycle arrest at the G1/S boundary enhances transient voltage-gated ion channel expression in human and insect cells. CELL REPORTS METHODS 2023; 3:100559. [PMID: 37751687 PMCID: PMC10545908 DOI: 10.1016/j.crmeth.2023.100559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 06/01/2023] [Accepted: 07/20/2023] [Indexed: 09/28/2023]
Abstract
Heterologous expression of recombinant ion channel subunits in cell lines is often limited by the presence of a low number of channels at the cell surface level. Here, we introduce a combination of two techniques: viral expression using the baculovirus system plus cell-cycle arrest at the G1/S boundary using either thymidine or hydroxyurea. This method achieved a manifold increase in the peak current density of expressed ion channels compared with the classical liposome-mediated transfection methods. The enhanced ionic current was accompanied by an increase in the density of gating charges, confirming that the increased yield of protein and ionic current reflects the functional localization of channels in the plasma membrane. This modified method of viral expression coordinated with the cell cycle arrest will pave the way to better decipher the structure and function of ion channels and their association with ion channelopathies.
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Affiliation(s)
- Ahmed Eltokhi
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA.
| | - William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA
| | - Tamer M Gamal El-Din
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA.
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10
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Abe K, Ozako M, Inukai M, Matsuyuki Y, Kitayama S, Kanai C, Nagai C, Gopalasingam CC, Gerle C, Shigematsu H, Umekubo N, Yokoshima S, Yoshimori A. Deep learning driven de novo drug design based on gastric proton pump structures. Commun Biol 2023; 6:956. [PMID: 37726448 PMCID: PMC10509173 DOI: 10.1038/s42003-023-05334-8] [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: 08/11/2023] [Accepted: 09/08/2023] [Indexed: 09/21/2023] Open
Abstract
Existing drugs often suffer in their effectiveness due to detrimental side effects, low binding affinity or pharmacokinetic problems. This may be overcome by the development of distinct compounds. Here, we exploit the rich structural basis of drug-bound gastric proton pump to develop compounds with strong inhibitory potency, employing a combinatorial approach utilizing deep generative models for de novo drug design with organic synthesis and cryo-EM structural analysis. Candidate compounds that satisfy pharmacophores defined in the drug-bound proton pump structures, were designed in silico utilizing our deep generative models, a workflow termed Deep Quartet. Several candidates were synthesized and screened according to their inhibition potencies in vitro, and their binding poses were in turn identified by cryo-EM. Structures reaching up to 2.10 Å resolution allowed us to evaluate and re-design compound structures, heralding the most potent compound in this study, DQ-18 (N-methyl-4-((2-(benzyloxy)-5-chlorobenzyl)oxy)benzylamine), which shows a Ki value of 47.6 nM. Further high-resolution cryo-EM analysis at 2.08 Å resolution unambiguously determined the DQ-18 binding pose. Our integrated approach offers a framework for structure-based de novo drug development based on the desired pharmacophores within the protein structure.
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Affiliation(s)
- Kazuhiro Abe
- Cellular and Structural Physiology Institute, Nagoya University, Nagoya, Aichi, 464-8601, Japan.
- Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan.
- Center for One Medicine Innovative Translational Research (COMIT), Nagoya University, Nagoya, Aichi, 464-8601, Japan.
| | - Mami Ozako
- Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Miki Inukai
- Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Yoe Matsuyuki
- Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Shinnosuke Kitayama
- Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Chisato Kanai
- INTAGE Healthcare, Inc., 3-5-7, Kawaramachi Chuo-ku, Osaka, 541-0048, Japan
| | - Chiaki Nagai
- Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | | | - Christoph Gerle
- RIKEN SPring-8 Center, Kouto, Sayo-gun, Hyogo, 679-5148, Japan
| | - Hideki Shigematsu
- Japan Synchrotron Radiation Research Institute (JASRI), SPring-8, 1-1-1 Kouto, Sayo, Hyogo, 679-5148, Japan
| | - Nariyoshi Umekubo
- Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Satoshi Yokoshima
- Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan.
| | - Atsushi Yoshimori
- Institute for Theoretical Medicine, Inc., 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa, 251-0012, Japan.
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11
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Tsutsumi N, Masoumi Z, James SC, Tucker JA, Winkelmann H, Grey W, Picton LK, Moss L, Wilson SC, Caveney NA, Jude KM, Gati C, Piehler J, Hitchcock IS, Garcia KC. Structure of the thrombopoietin-MPL receptor complex is a blueprint for biasing hematopoiesis. Cell 2023; 186:4189-4203.e22. [PMID: 37633268 PMCID: PMC10528194 DOI: 10.1016/j.cell.2023.07.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 06/26/2023] [Accepted: 07/28/2023] [Indexed: 08/28/2023]
Abstract
Thrombopoietin (THPO or TPO) is an essential cytokine for hematopoietic stem cell (HSC) maintenance and megakaryocyte differentiation. Here, we report the 3.4 Å resolution cryoelectron microscopy structure of the extracellular TPO-TPO receptor (TpoR or MPL) signaling complex, revealing the basis for homodimeric MPL activation and providing a structural rationalization for genetic loss-of-function thrombocytopenia mutations. The structure guided the engineering of TPO variants (TPOmod) with a spectrum of signaling activities, from neutral antagonists to partial- and super-agonists. Partial agonist TPOmod decoupled JAK/STAT from ERK/AKT/CREB activation, driving a bias for megakaryopoiesis and platelet production without causing significant HSC expansion in mice and showing superior maintenance of human HSCs in vitro. These data demonstrate the functional uncoupling of the two primary roles of TPO, highlighting the potential utility of TPOmod in hematology research and clinical HSC transplantation.
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Affiliation(s)
- Naotaka Tsutsumi
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan.
| | - Zahra Masoumi
- York Biomedical Research Institute, Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Sophie C James
- York Biomedical Research Institute, Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Julie A Tucker
- York Biomedical Research Institute, Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Hauke Winkelmann
- Department of Biology/Chemistry and Center of Cellular Nanoanalytics, Osnabrück University, 49076 Osnabrück, Germany
| | - William Grey
- York Biomedical Research Institute, Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Lora K Picton
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lucie Moss
- York Biomedical Research Institute, Department of Biology, University of York, Heslington, York YO10 5DD, UK
| | - Steven C Wilson
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Nathanael A Caveney
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kevin M Jude
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Cornelius Gati
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Biosciences Division, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA
| | - Jacob Piehler
- Department of Biology/Chemistry and Center of Cellular Nanoanalytics, Osnabrück University, 49076 Osnabrück, Germany
| | - Ian S Hitchcock
- York Biomedical Research Institute, Department of Biology, University of York, Heslington, York YO10 5DD, UK.
| | - K Christopher Garcia
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA.
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12
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Kim A, Park JH, Lee MJ, Kim SM. Interferon alpha and beta receptor 1 knockout in human embryonic kidney 293 cells enhances the production efficiency of proteins or adenoviral vectors related to type I interferons. Front Bioeng Biotechnol 2023; 11:1192291. [PMID: 37476482 PMCID: PMC10355049 DOI: 10.3389/fbioe.2023.1192291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 05/16/2023] [Indexed: 07/22/2023] Open
Abstract
Human embryonic kidney (HEK) 293 cells are widely used in protein and viral vector production owing to their high transfection efficiency, rapid growth, and suspension growth capability. Given their antiviral, anticancer, and immune-enhancing effects, type I interferons (IFNs) have been used to prevent and treat human and animal diseases. However, the binding of type I IFNs to the IFN-α and-β receptor (IFNAR) stimulates the expression of IFN-stimulated genes (ISGs). This phenomenon induces an antiviral state and promotes apoptosis in cells, thereby impeding protein or viral vector production. In this study, we generated an IFNAR subtype 1 knockout (KO) HEK 293 suspension (IFNAR-KO) cell line by using clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein-9 nuclease (Cas9) technology. Upon treatment with human IFN-α, the IFNAR-KO cells showed a constant expression of ISGs, including 2'-5'-oligoadenylate synthetase 1 (OAS1), myxovirus resistance 1 (Mx1), protein kinase RNA-activated (PKR), and IFN-induced transmembrane protein 1 (IFITM1), when compared with the wild-type HEK 293 (WT) cells, wherein the ISGs were significantly upregulated. As a result, the titer of recombinant adenovirus expressing porcine IFN-α was significantly higher in the IFNAR-KO cells than in the WT cells. Furthermore, the IFNAR-KO cells continuously produced higher amounts of IFN-α protein than the WT cells. Thus, the CRISPR-Cas9-mediated IFNAR1 KO cell line can improve the production efficiency of proteins or viral vectors related to IFNs. The novel cell line may be used for producing vaccines and elucidating the type I IFN signaling pathway in cells.
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13
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Abstract
This chapter explores the existing structural and functional studies on the endo-lysosomal channel TRPML1 and its analogs TRPML2, TRPML3. These channels represent the mucolipin subfamily of the TRP channel superfamily comprising important roles in sensory physiology, ion homeostasis, and signal transduction. Since 2016, numerous structures have been determined for all three members using either cryo-EM or X-ray crystallography. These studies along with recent functional analysis have considerably strengthened our knowledge on TRPML channels and its related endo-lysosomal function. This chapter, together with relevant reports in other chapters from this handbook, provides an informative and detailed tool to study the endo-lysosomal cation channels.
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Affiliation(s)
- Michael Fine
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Xiaochun Li
- Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
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14
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Lin Z, Li Y, Hang Y, Wang C, Liu B, Li J, Yin L, Jiang X, Du X, Qiao Z, Zhu F, Zhang Z, Zhang Q, Zhou Z. Tuning the Size of Large Dense-Core Vesicles and Quantal Neurotransmitter Release via Secretogranin II Liquid-Liquid Phase Separation. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202263. [PMID: 35896896 PMCID: PMC9507364 DOI: 10.1002/advs.202202263] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 06/12/2022] [Indexed: 06/15/2023]
Abstract
Large dense-core vesicles (LDCVs) are larger in volume than synaptic vesicles, and are filled with multiple neuropeptides, hormones, and neurotransmitters that participate in various physiological processes. However, little is known about the mechanism determining the size of LDCVs. Here, it is reported that secretogranin II (SgII), a vesicle matrix protein, contributes to LDCV size regulation through its liquid-liquid phase separation in neuroendocrine cells. First, SgII undergoes pH-dependent polymerization and the polymerized SgII forms phase droplets with Ca2+ in vitro and in vivo. Further, the Ca2+ -induced SgII droplets recruit reconstituted bio-lipids, mimicking the LDCVs biogenesis. In addition, SgII knockdown leads to significant decrease of the quantal neurotransmitter release by affecting LDCV size, which is differently rescued by SgII truncations with different degrees of phase separation. In conclusion, it is shown that SgII is a unique intravesicular matrix protein undergoing liquid-liquid phase separation, and present novel insights into how SgII determines LDCV size and the quantal neurotransmitter release.
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Affiliation(s)
- Zhaohan Lin
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| | - Yinglin Li
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| | - Yuqi Hang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| | - Changhe Wang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| | - Bing Liu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| | - Jie Li
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| | - Lili Yin
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| | - Xiaohan Jiang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| | - Xingyu Du
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| | - Zhongjun Qiao
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| | - Feipeng Zhu
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| | - Zhe Zhang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| | - Quanfeng Zhang
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
| | - Zhuan Zhou
- State Key Laboratory of Membrane Biology and Beijing Key Laboratory of Cardiometabolic Molecular MedicineInstitute of Molecular MedicineCollege of Future TechnologyPeking‐Tsinghua Center for Life Sciences, and PKU‐IDG/McGovern Institute for Brain ResearchPeking UniversityBeijing100871China
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15
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Wilson SC, Caveney NA, Yen M, Pollmann C, Xiang X, Jude KM, Hafer M, Tsutsumi N, Piehler J, Garcia KC. Organizing structural principles of the IL-17 ligand-receptor axis. Nature 2022; 609:622-629. [PMID: 35863378 PMCID: PMC9477748 DOI: 10.1038/s41586-022-05116-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 07/15/2022] [Indexed: 12/01/2022]
Abstract
The IL-17 family of cytokines and receptors have central roles in host defence against infection and development of inflammatory diseases1. The compositions and structures of functional IL-17 family ligand-receptor signalling assemblies remain unclear. IL-17E (also known as IL-25) is a key regulator of type 2 immune responses and driver of inflammatory diseases, such as allergic asthma, and requires both IL-17 receptor A (IL-17RA) and IL-17RB to elicit functional responses2. Here we studied IL-25-IL-17RB binary and IL-25-IL-17RB-IL-17RA ternary complexes using a combination of cryo-electron microscopy, single-molecule imaging and cell-based signalling approaches. The IL-25-IL-17RB-IL-17RA ternary signalling assembly is a C2-symmetric complex in which the IL-25-IL-17RB homodimer is flanked by two 'wing-like' IL-17RA co-receptors through a 'tip-to-tip' geometry that is the key receptor-receptor interaction required for initiation of signal transduction. IL-25 interacts solely with IL-17RB to allosterically promote the formation of the IL-17RB-IL-17RA tip-to-tip interface. The resulting large separation between the receptors at the membrane-proximal level may reflect proximity constraints imposed by the intracellular domains for signalling. Cryo-electron microscopy structures of IL-17A-IL-17RA and IL-17A-IL-17RA-IL-17RC complexes reveal that this tip-to-tip architecture is a key organizing principle of the IL-17 receptor family. Furthermore, these studies reveal dual actions for IL-17RA sharing among IL-17 cytokine complexes, by either directly engaging IL-17 cytokines or alternatively functioning as a co-receptor.
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Affiliation(s)
- Steven C Wilson
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Nathanael A Caveney
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Michelle Yen
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Christoph Pollmann
- Divison of Biophysics, Department of Biology, University of Osnabrück, Osnabrück, Germany
| | - Xinyu Xiang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Kevin M Jude
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Maximillian Hafer
- Divison of Biophysics, Department of Biology, University of Osnabrück, Osnabrück, Germany
| | - Naotaka Tsutsumi
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Jacob Piehler
- Divison of Biophysics, Department of Biology, University of Osnabrück, Osnabrück, Germany
| | - K Christopher Garcia
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.
- Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA.
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16
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Greven JA, Brett TJ. Production of Eukaryotic Glycoproteins for Structural and Functional Studies Using Expi293F Cells. Curr Protoc 2022; 2:e512. [PMID: 35998009 PMCID: PMC9405080 DOI: 10.1002/cpz1.512] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Milligram quantities of pure proteins are required for structural, functional, and pharmaceutical screening studies. These requirements can be challenging for a majority of important therapeutic targets that are secreted glycoproteins, receptors, membrane proteins, or large cytosolic complexes. Here, we present protocols for producing and purifying large amounts of secreted glycoproteins using the mammalian cell-based Expi293F system via large-scale transient transfection. This system can be easily adapted for the production of membrane proteins and large cytosolic complexes. The method can be utilized to quickly evaluate numerous expression constructs to identify optimal expressers. Use of mammalian cells ensures proper post-translational modifications, including disulfide bonds and glycosylation, that can be important for accurate functional studies. In addition, minor modifications can be introduced to produce labeled or deglycosylated proteins for structural studies by X-ray crystallography, nuclear magnetic resonance, or cryo-electron microscopy. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Production of milligram quantities of plasmid DNA for large-scale transient transfection Basic Protocol 2: Large-scale culture and transient transfection of Expi293F cells Basic Protocol 3: Purification of hexahistidine-tagged proteins from medium.
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Affiliation(s)
- Jessica A. Greven
- Department of Medicine, Division of Pulmonary and Critical Care, Washington University School of Medicine, Saint Louis, MO 63110
| | - Tom J. Brett
- Department of Medicine, Division of Pulmonary and Critical Care, Washington University School of Medicine, Saint Louis, MO 63110
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO 63110
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO 63110
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17
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The dopamine transporter antiports potassium to increase the uptake of dopamine. Nat Commun 2022; 13:2446. [PMID: 35508541 PMCID: PMC9068915 DOI: 10.1038/s41467-022-30154-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 04/18/2022] [Indexed: 12/11/2022] Open
Abstract
The dopamine transporter facilitates dopamine reuptake from the extracellular space to terminate neurotransmission. The transporter belongs to the neurotransmitter:sodium symporter family, which includes transporters for serotonin, norepinephrine, and GABA that utilize the Na+ gradient to drive the uptake of substrate. Decades ago, it was shown that the serotonin transporter also antiports K+, but investigations of K+-coupled transport in other neurotransmitter:sodium symporters have been inconclusive. Here, we show that ligand binding to the Drosophila- and human dopamine transporters are inhibited by K+, and the conformational dynamics of the Drosophila dopamine transporter in K+ are divergent from the apo- and Na+-states. Furthermore, we find that K+ increases dopamine uptake by the Drosophila dopamine transporter in liposomes, and visualize Na+ and K+ fluxes in single proteoliposomes using fluorescent ion indicators. Our results expand on the fundamentals of dopamine transport and prompt a reevaluation of the impact of K+ on other transporters in this pharmacologically important family. The dopamine transporter, DAT, controls dopamine signaling by facilitating its reuptake using the Na+ gradient as driving force. Here, the authors uncover that an antiport of K+ ions also contributes to setting the rate of DAT-mediated dopamine clearance.
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18
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Transduction of HEK293 Cells with BacMam Baculovirus Is an Efficient System for the Production of HIV-1 Virus-like Particles. Viruses 2022; 14:v14030636. [PMID: 35337043 PMCID: PMC8954388 DOI: 10.3390/v14030636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/06/2022] [Accepted: 03/15/2022] [Indexed: 12/13/2022] Open
Abstract
Gag virus-like particles (VLPs) are promising vaccine candidates against infectious diseases. VLPs are generally produced using the insect cell/baculovirus expression vector system (BEVS), or in mammalian cells by plasmid DNA transient gene expression (TGE). However, VLPs produced with the insect cell/BEVS are difficult to purify and might not display the appropriate post-translational modifications, whereas plasmid DNA TGE approaches are expensive and have a limited scale-up capability. In this study, the production of Gag VLPs with the BacMam expression system in a suspension culture of HEK293 cells is addressed. The optimal conditions of multiplicity of infection (MOI), viable cell density (VCD) at infection, and butyric acid (BA) concentration that maximize cell transduction and VLP production are determined. In these conditions, a maximum cell transduction efficiency of 91.5 ± 1.1%, and a VLP titer of 2.8 ± 0.1 × 109 VLPs/mL are achieved. Successful VLP generation in transduced HEK293 cells is validated using super-resolution fluorescence microscopy, with VLPs produced resembling immature HIV-1 virions and with an average size comprised in the 100–200 nm range. Additionally, evidence that BacMam transduction occurs via different pathways including dynamin-mediated endocytosis and macropinocytosis is provided. This work puts the basis for future studies aiming at scaling up the BacMam baculovirus system as an alternative strategy for VLP production.
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19
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Kuzuya M, Hirano H, Hayashida K, Watanabe M, Kobayashi K, Terada T, Mahmood MI, Tama F, Tani K, Fujiyoshi Y, Oshima A. Structures of human pannexin-1 in nanodiscs reveal gating mediated by dynamic movement of the N terminus and phospholipids. Sci Signal 2022; 15:eabg6941. [PMID: 35133866 DOI: 10.1126/scisignal.abg6941] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Pannexin (PANX) family proteins form large-pore channels that mediate purinergic signaling. We analyzed the cryo-EM structures of human PANX1 in lipid nanodiscs to elucidate the gating mechanism and its regulation by the amino terminus in phospholipids. The wild-type channel has an amino-terminal funnel in the pore, but in the presence of the inhibitor probenecid, a cytoplasmically oriented amino terminus and phospholipids obstruct the pore. Functional analysis using whole-cell patch-clamp and oocyte voltage clamp showed that PANX1 lacking the amino terminus did not open and had a dominant negative effect on channel activity, thus confirming that the amino-terminal domain played an essential role in channel opening. These observations suggest that dynamic conformational changes in the amino terminus of human PANX1 are associated with lipid movement in and out of the pore. Moreover, the data provide insight into the gating mechanism of PANX1 and, more broadly, other large-pore channels.
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Affiliation(s)
- Maki Kuzuya
- Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Hidemi Hirano
- Cellular and Structural Physiology Institute (CeSPI), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Kenichi Hayashida
- Cellular and Structural Physiology Institute (CeSPI), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Masakatsu Watanabe
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | | | - Tohru Terada
- Department of Biotechnology, Graduate School of Agricultural and Life Sciences, University of Tokyo, 1-1-1 Yayoi, Bunkyō-ku, Tokyo 113-8657, Japan
| | - Md Iqbal Mahmood
- Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Florence Tama
- Department of Physics, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.,Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.,RIKEN Center for Computational Science, Kobe, Hyogo 650-0047, Japan
| | - Kazutoshi Tani
- Graduate School of Medicine, Mie University, 2-174 Edobashi Tsu, Mie 514-8507, Japan
| | - Yoshinori Fujiyoshi
- Advanced Research Institute, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyō-ku, Tokyo 113-8510, Japan.,CeSPIA Inc., Otemachi, Chiyoda, Tokyo 100-0004, Japan
| | - Atsunori Oshima
- Department of Basic Medicinal Sciences, Graduate School of Pharmaceutical Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.,Cellular and Structural Physiology Institute (CeSPI), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.,Institute for Glyco-core Research (iGCORE), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
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20
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Guo W, Wang M, Chen L. A co-expression vector for baculovirus-mediated protein expression in mammalian cells. Biochem Biophys Res Commun 2022; 594:69-73. [DOI: 10.1016/j.bbrc.2022.01.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 01/13/2022] [Indexed: 11/02/2022]
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21
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Bruguera ES, Mahoney JP, Weis WI. Reconstitution of purified membrane protein dimers in lipid nanodiscs with defined stoichiometry and orientation using a split GFP tether. J Biol Chem 2022; 298:101628. [PMID: 35074428 PMCID: PMC8980801 DOI: 10.1016/j.jbc.2022.101628] [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: 12/10/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 12/12/2022] Open
Abstract
Many membrane proteins function as dimers or larger oligomers, including transporters, channels, certain signaling receptors, and adhesion molecules. In some cases, the interactions between individual proteins may be weak and/or dependent on specific lipids, such that detergent solubilization used for biochemical and structural studies disrupts functional oligomerization. Solubilized membrane protein oligomers can be captured in lipid nanodiscs, but this is an inefficient process that can produce stoichiometrically and topologically heterogeneous preparations. Here, we describe a technique to obtain purified homogeneous membrane protein dimers in nanodiscs using a split GFP (sGFP) tether. Complementary sGFP tags associate to tether the coexpressed dimers and control both stoichiometry and orientation within the nanodiscs, as assessed by quantitative Western blotting and negative-stain EM. The sGFP tether confers several advantages over other methods: it is highly stable in solution and in SDS-PAGE, which facilitates screening of dimer expression and purification by fluorescence, and also provides a dimer-specific purification handle for use with GFP nanobody–conjugated resin. We used this method to purify a Frizzled-4 homodimer and a Frizzled-4/low-density lipoprotein receptor–related protein 6 heterodimer in nanodiscs. These examples demonstrate the utility and flexibility of this method, which enables subsequent mechanistic molecular and structural studies of membrane protein pairs.
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Affiliation(s)
- Elise S Bruguera
- Departments of Molecular & Cellular Physiology and Structural Biology, Stanford University School of Medicine; Stanford, CA 94305
| | - Jacob P Mahoney
- Departments of Molecular & Cellular Physiology and Structural Biology, Stanford University School of Medicine; Stanford, CA 94305
| | - William I Weis
- Departments of Molecular & Cellular Physiology and Structural Biology, Stanford University School of Medicine; Stanford, CA 94305.
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22
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Nakanishi H, Hayashida K, Nishizawa T, Oshima A, Abe K. Cryo-EM of the ATP11C flippase reconstituted in Nanodiscs shows a distended phospholipid bilayer inner membrane around transmembrane helix 2. J Biol Chem 2021; 298:101498. [PMID: 34922944 PMCID: PMC8733269 DOI: 10.1016/j.jbc.2021.101498] [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: 11/06/2021] [Revised: 12/08/2021] [Accepted: 12/10/2021] [Indexed: 11/26/2022] Open
Abstract
ATP11C is a member of the P4-ATPase flippase family that mediates translocation of phosphatidylserine (PtdSer) across the lipid bilayer. In order to characterize the structure and function of ATP11C in a model natural lipid environment, we revisited and optimized a quick procedure for reconstituting ATP11C into Nanodiscs using methyl-β-cyclodextrin as a reagent for the detergent removal. ATP11C was efficiently reconstituted with the endogenous lipid, or the mixture of endogenous lipid and synthetic dioleoylphosphatidylcholine (DOPC)/dioleoylphosphatidylserine (DOPS), all of which retained the ATPase activity. We obtained 3.4 Å and 3.9 Å structures using single-particle cryo-electron microscopy (cryo-EM) of AlF- and BeF-stabilized ATP11C transport intermediates, respectively, in a bilayer containing DOPS. We show that the latter exhibited a distended inner membrane around ATP11C transmembrane helix 2, possibly reflecting the perturbation needed for phospholipid release to the lipid bilayer. Our structures of ATP11C in the lipid membrane indicate that the membrane boundary varies upon conformational changes of the enzyme and is no longer flat around the protein, a change that likely contributes to phospholipid translocation across the membrane leaflets.
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Affiliation(s)
- Hanayo Nakanishi
- Cellular and Structural Physiology Institute, Nagoya University, 464-8601, Japan
| | - Kenichi Hayashida
- Cellular and Structural Physiology Institute, Nagoya University, 464-8601, Japan
| | - Tomohiro Nishizawa
- Graduate School of Medical Life Science, Yokohama City University, Tsurumi, Yokohama, 230-0045, Japan
| | - Atsunori Oshima
- Cellular and Structural Physiology Institute, Nagoya University, 464-8601, Japan; Graduate School of Pharmaceutical Sciences, Nagoya University, 464-8601, Japan; Institute for Glyco-core Research (iGCORE), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Kazuhiro Abe
- Cellular and Structural Physiology Institute, Nagoya University, 464-8601, Japan; Graduate School of Pharmaceutical Sciences, Nagoya University, 464-8601, Japan.
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Wang J, Miao Y, Wicklein R, Sun Z, Wang J, Jude KM, Fernandes RA, Merrill SA, Wernig M, Garcia KC, Südhof TC. RTN4/NoGo-receptor binding to BAI adhesion-GPCRs regulates neuronal development. Cell 2021; 184:5869-5885.e25. [PMID: 34758294 PMCID: PMC8620742 DOI: 10.1016/j.cell.2021.10.016] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/01/2021] [Accepted: 10/13/2021] [Indexed: 10/19/2022]
Abstract
RTN4-binding proteins were widely studied as "NoGo" receptors, but their physiological interactors and roles remain elusive. Similarly, BAI adhesion-GPCRs were associated with numerous activities, but their ligands and functions remain unclear. Using unbiased approaches, we observed an unexpected convergence: RTN4 receptors are high-affinity ligands for BAI adhesion-GPCRs. A single thrombospondin type 1-repeat (TSR) domain of BAIs binds to the leucine-rich repeat domain of all three RTN4-receptor isoforms with nanomolar affinity. In the 1.65 Å crystal structure of the BAI1/RTN4-receptor complex, C-mannosylation of tryptophan and O-fucosylation of threonine in the BAI TSR-domains creates a RTN4-receptor/BAI interface shaped by unusual glycoconjugates that enables high-affinity interactions. In human neurons, RTN4 receptors regulate dendritic arborization, axonal elongation, and synapse formation by differential binding to glial versus neuronal BAIs, thereby controlling neural network activity. Thus, BAI binding to RTN4/NoGo receptors represents a receptor-ligand axis that, enabled by rare post-translational modifications, controls development of synaptic circuits.
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Affiliation(s)
- Jie Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yi Miao
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Rebecca Wicklein
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Zijun Sun
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jinzhao Wang
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Institute for Stem Cell Biology and Regenerative Medicine, Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kevin M Jude
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ricardo A Fernandes
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sean A Merrill
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Marius Wernig
- Institute for Stem Cell Biology and Regenerative Medicine, Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - K Christopher Garcia
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA.
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24
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Studies of SMOOTHENED Activation in Cell-Free and Reconstituted Systems. Methods Mol Biol 2021. [PMID: 34562251 DOI: 10.1007/978-1-0716-1701-4_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Much of our current understanding of Hedgehog signal transduction derives from studies involving intact cells and organisms. Here we describe the use of cell-free and reconstituted systems to study a key step in Hedgehog signal transduction: the activation of SMOOTHENED by membrane lipids. These methods can be adapted to study other steps in Hedgehog signal transduction, particularly those that occur at the membrane.
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25
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Abstract
Mammalian protein expression systems are ideally suited for the high-level production of recombinant eukaryotic secreted and membrane proteins for structural biology applications. Here, we present genetic transduction of HEK293-derived cells using lentivirus as a robust and cost-efficient method for the rapid generation of stable expression cell lines. We describe the features of the lentiviral transfer plasmid pHR-CMV-TetO2, as well as detailed protocols for production of lentiviral particles, determination of functional lentiviral titer, infection of expression cells, culture and expansion of the resulting stable cell lines, their adaptation to adherent and suspension growth, and constitutive or inducible milligram-scale protein production. The typical lead-time for a full production run is ~3-4 weeks, with an anticipated yield of up to tens of milligrams of protein per liter of expression medium.
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26
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Varikkodan MM, Chen CC, Wu TY. Recombinant Baculovirus: A Flexible Drug Screening Platform for Chikungunya Virus. Int J Mol Sci 2021; 22:ijms22157891. [PMID: 34360656 PMCID: PMC8347121 DOI: 10.3390/ijms22157891] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/12/2021] [Accepted: 07/21/2021] [Indexed: 11/16/2022] Open
Abstract
Chikungunya virus (CHIKV) is a mosquito-transmitted infectious agent that causes an endemic or epidemic outbreak(s) of Chikungunya fever that is reported in almost all countries. This virus is an intense global threat, due to its high rate of contagion and the lack of effective remedies. In this study, we developed two baculovirus expression vector system (BEVS)-based approaches for the screening of anti-CHIKV drugs in Spodoptera frugiperda insect (Sf21) cells and U-2OS cells. First, structural protein of CHIKV was co-expressed through BEVS and thereby induced cell fusion in Sf21 cells. We used an internal ribosome entry site (IRES) to co-express the green fluorescent protein (EGFP) for identifying these fusion events. The EGFP-positive Sf21 cells fused with each other and with uninfected cells to form syncytia. We identified that ursolic acid has potential anti-CHIKV activity in vitro, by using this approach. Second, BacMam virus-based gene delivery has been successfully applied for the transient expression of non-structural proteins with a subgenomic promoter-EGFP (SP-EGFP) cassette in U-2OS cells to act as an in vitro CHIKV replicon system. Our BacMam-based screening system has identified that the potential effects of baicalin and baicalein phytocompounds can inhibit the replicon activity of CHIKV in U-2OS cells. In conclusion, our results suggested that BEVS can be a potential tool for screening drugs against CHIKV.
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Affiliation(s)
- Muhammed Muhsin Varikkodan
- Department of Chemistry, Chung Yuan Christian University, Chungli 320, Taiwan;
- Department of Bioscience Technology, Chung Yuan Christian University, Chungli 320, Taiwan;
| | - Chun-Chung Chen
- Department of Bioscience Technology, Chung Yuan Christian University, Chungli 320, Taiwan;
| | - Tzong-Yuan Wu
- Department of Chemistry, Chung Yuan Christian University, Chungli 320, Taiwan;
- Department of Bioscience Technology, Chung Yuan Christian University, Chungli 320, Taiwan;
- Correspondence: ; Tel.: +886-3-2653520
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27
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Tsutsumi N, Qu Q, Mavri M, Baggesen MS, Maeda S, Waghray D, Berg C, Kobilka BK, Rosenkilde MM, Skiniotis G, Garcia KC. Structural basis for the constitutive activity and immunomodulatory properties of the Epstein-Barr virus-encoded G protein-coupled receptor BILF1. Immunity 2021; 54:1405-1416.e7. [PMID: 34216564 DOI: 10.1016/j.immuni.2021.06.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 03/21/2021] [Accepted: 06/01/2021] [Indexed: 12/22/2022]
Abstract
Epstein-Barr virus (EBV) encodes a G protein-coupled receptor (GPCR) termed BILF1 that is essential for EBV-mediated immunosuppression and oncogenesis. BILF1 couples with inhibitory G protein (Gi), the major intracellular signaling effector for human chemokine receptors, and exhibits constitutive signaling activity; the ligand(s) for BILF1 are unknown. We studied the origins of BILF1's constitutive activity through structure determination of BILF1 bound to the inhibitory G protein (Gi) heterotrimer. The 3.2-Å resolution cryo-electron microscopy structure revealed an extracellular loop within BILF1 that blocked the typical chemokine binding site, suggesting ligand-autonomous receptor activation. Rather, amino acid substitutions within BILF1 transmembrane regions at hallmark ligand-activated class A GPCR "microswitches" stabilized a constitutively active BILF1 conformation for Gi coupling in a ligand-independent fashion. Thus, the constitutive activity of BILF1 promotes immunosuppression and virulence independent of ligand availability, with implications for the function of GPCRs encoded by related viruses and for therapeutic targeting of EBV.
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Affiliation(s)
- Naotaka Tsutsumi
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA
| | - Qianhui Qu
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Maša Mavri
- Department of Biomedical Sciences, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark; Institute of Preclinical Sciences, Veterinary Faculty, University of Ljubljana, Ljubljana, Slovenia
| | - Maibritt S Baggesen
- Department of Biomedical Sciences, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Shoji Maeda
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Deepa Waghray
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Christian Berg
- Department of Biomedical Sciences, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Brian K Kobilka
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Science, University of Copenhagen, Copenhagen, Denmark
| | - Georgios Skiniotis
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - K Christopher Garcia
- Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA; Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA, USA.
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28
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Puthenveetil R, Lee CJ, Banerjee A. Production of Recombinant Transmembrane Proteins from Mammalian Cells for Biochemical and Structural Analyses. ACTA ACUST UNITED AC 2021; 87:e106. [PMID: 32515556 DOI: 10.1002/cpcb.106] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Eukaryotic integral membrane proteins are key components of various biological processes. Because they are implicated in multiple diseases, it is important to understand their mechanism of action by elucidating their structure and function. Complex technical challenges associated with the generation of recombinant membrane proteins severely impair our ability to understand them using structural and biochemical methods. Here, we provide a detailed procedure to address and mitigate difficulties involved in the large-scale heterologous overexpression and purification of eukaryotic membrane proteins using HEK293S GnTi- cells transduced with baculovirus. Two human proteins, hDHHC15 and hPORCN, are presented as examples, with step-by-step instructions for transient transfection and generation of baculoviruses, followed by overexpression and purification from HEK293S GnTi- cells. © 2020 Wiley Periodicals LLC. Basic Protocol 1: Small-scale protein expression in mammalian HEK293T cells Basic Protocol 2: Generation of baculovirus from Sf9 (insect) cells Alternate Protocol: Enumeration-free method for generating P2 viral stock Support Protocol 1: Small-scale transduction of HEK293T cells with P2 baculovirus Basic Protocol 3: Large-scale viral transduction of HEK293S GnTi- cells Support Protocol 2: Large-scale membrane preparation from HEK293S GnTi- cells Basic Protocol 4: Large-scale purification of membrane proteins from HEK293S GnTi- cells.
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Affiliation(s)
- Robbins Puthenveetil
- Unit on Structural and Chemical Biology of Membrane Proteins, Neurosciences and Cellular and Structural Biology Division (NCSBD), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland
| | - Chul-Jin Lee
- Unit on Structural and Chemical Biology of Membrane Proteins, Neurosciences and Cellular and Structural Biology Division (NCSBD), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland
| | - Anirban Banerjee
- Unit on Structural and Chemical Biology of Membrane Proteins, Neurosciences and Cellular and Structural Biology Division (NCSBD), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland
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29
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Khalaj AJ, Sterky FH, Sclip A, Schwenk J, Brunger AT, Fakler B, Südhof TC. Deorphanizing FAM19A proteins as pan-neurexin ligands with an unusual biosynthetic binding mechanism. J Cell Biol 2021; 219:151974. [PMID: 32706374 PMCID: PMC7480106 DOI: 10.1083/jcb.202004164] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/01/2020] [Accepted: 06/05/2020] [Indexed: 12/14/2022] Open
Abstract
Neurexins are presynaptic adhesion molecules that organize synapses by binding to diverse trans-synaptic ligands, but how neurexins are regulated is incompletely understood. Here we identify FAM19A/TAFA proteins, “orphan" cytokines, as neurexin regulators that interact with all neurexins, except for neurexin-1γ, via an unusual mechanism. Specifically, we show that FAM19A1-A4 bind to the cysteine-loop domain of neurexins by forming intermolecular disulfide bonds during transport through the secretory pathway. FAM19A-binding required both the cysteines of the cysteine-loop domain and an adjacent sequence of neurexins. Genetic deletion of neurexins suppressed FAM19A1 expression, demonstrating that FAM19As physiologically interact with neurexins. In hippocampal cultures, expression of exogenous FAM19A1 decreased neurexin O-glycosylation and suppressed its heparan sulfate modification, suggesting that FAM19As regulate the post-translational modification of neurexins. Given the selective expression of FAM19As in specific subtypes of neurons and their activity-dependent regulation, these results suggest that FAM19As serve as cell type–specific regulators of neurexin modifications.
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Affiliation(s)
- Anna J Khalaj
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA
| | - Fredrik H Sterky
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA
| | - Alessandra Sclip
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA
| | - Jochen Schwenk
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA
| | - Bernd Fakler
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.,Centres for Biological Signalling Studies (BIOSS) and Integrative Biological Signalling Studies (CIBSS), Freiburg, Germany.,Center for Basics in NeuroModulation, Freiburg, Germany
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA
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30
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Glassman CR, Mathiharan YK, Jude KM, Su L, Panova O, Lupardus PJ, Spangler JB, Ely LK, Thomas C, Skiniotis G, Garcia KC. Structural basis for IL-12 and IL-23 receptor sharing reveals a gateway for shaping actions on T versus NK cells. Cell 2021; 184:983-999.e24. [PMID: 33606986 PMCID: PMC7899134 DOI: 10.1016/j.cell.2021.01.018] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 11/23/2020] [Accepted: 01/14/2021] [Indexed: 02/06/2023]
Abstract
Interleukin-12 (IL-12) and IL-23 are heterodimeric cytokines that are produced by antigen-presenting cells to regulate the activation and differentiation of lymphocytes, and they share IL-12Rβ1 as a receptor signaling subunit. We present a crystal structure of the quaternary IL-23 (IL-23p19/p40)/IL-23R/IL-12Rβ1 complex, together with cryoelectron microscopy (cryo-EM) maps of the complete IL-12 (IL-12p35/p40)/IL-12Rβ2/IL-12Rβ1 and IL-23 receptor (IL-23R) complexes, which reveal "non-canonical" topologies where IL-12Rβ1 directly engages the common p40 subunit. We targeted the shared IL-12Rβ1/p40 interface to design a panel of IL-12 partial agonists that preserved interferon gamma (IFNγ) induction by CD8+ T cells but impaired cytokine production from natural killer (NK) cells in vitro. These cell-biased properties were recapitulated in vivo, where IL-12 partial agonists elicited anti-tumor immunity to MC-38 murine adenocarcinoma absent the NK-cell-mediated toxicity seen with wild-type IL-12. Thus, the structural mechanism of receptor sharing used by IL-12 family cytokines provides a protein interface blueprint for tuning this cytokine axis for therapeutics.
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Affiliation(s)
- Caleb R Glassman
- Program in Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yamuna Kalyani Mathiharan
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kevin M Jude
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Leon Su
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ouliana Panova
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Patrick J Lupardus
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jamie B Spangler
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lauren K Ely
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Christoph Thomas
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Georgios Skiniotis
- Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - K Christopher Garcia
- Program in Immunology, Stanford University School of Medicine, Stanford, CA 94305, USA; Departments of Molecular and Cellular Physiology and Structural Biology, Stanford University School of Medicine, Stanford, CA 94305, USA; Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305, USA.
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31
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Mahajan P, Ellis K, Mukhopadhyay S, Fernandez-Cid A, Chi G, Man H, Dürr KL, Burgess-Brown NA. Expression Screening of Human Integral Membrane Proteins Using BacMam. Methods Mol Biol 2021; 2199:95-115. [PMID: 33125646 DOI: 10.1007/978-1-0716-0892-0_6] [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: 12/13/2022]
Abstract
This chapter describes the step-by-step methods employed by the Structural Genomics Consortium (SGC) for screening and producing proteins in the BacMam system. This eukaryotic expression system was selected and a screening process established in 2016 to enable production of highly challenging human integral membrane proteins (IMPs), which are a significant component of our target list. Here, we discuss our recently developed platform for identifying expression and monodispersity of IMPs from 3 mL of HEK293 cells.
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Affiliation(s)
| | | | | | | | - Gamma Chi
- Structural Genomics Consortium, University of Oxford, Oxford, UK
| | - Henry Man
- Structural Genomics Consortium, University of Oxford, Oxford, UK
| | - Katharina L Dürr
- Structural Genomics Consortium, University of Oxford, Oxford, UK
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32
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Kermani AA. A guide to membrane protein X‐ray crystallography. FEBS J 2020; 288:5788-5804. [DOI: 10.1111/febs.15676] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 11/17/2020] [Accepted: 12/14/2020] [Indexed: 12/18/2022]
Affiliation(s)
- Ali A. Kermani
- Department of Molecular, Cellular, and Developmental Biology University of Michigan Ann Arbor MI USA
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33
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Dumitru AC, Deepak RNVK, Liu H, Koehler M, Zhang C, Fan H, Alsteens D. Submolecular probing of the complement C5a receptor-ligand binding reveals a cooperative two-site binding mechanism. Commun Biol 2020; 3:786. [PMID: 33339958 PMCID: PMC7749166 DOI: 10.1038/s42003-020-01518-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 11/20/2020] [Indexed: 01/10/2023] Open
Abstract
A current challenge to produce effective therapeutics is to accurately determine the location of the ligand-biding site and to characterize its properties. So far, the mechanisms underlying the functional activation of cell surface receptors by ligands with a complex binding mechanism remain poorly understood due to a lack of suitable nanoscopic methods to study them in their native environment. Here, we elucidated the ligand-binding mechanism of the human G protein-coupled C5a receptor (C5aR). We discovered for the first time a cooperativity between the two orthosteric binding sites. We found that the N-terminus C5aR serves as a kinetic trap, while the transmembrane domain acts as the functional site and both contributes to the overall high-affinity interaction. In particular, Asp282 plays a key role in ligand binding thermodynamics, as revealed by atomic force microscopy and steered molecular dynamics simulation. Our findings provide a new structural basis for the functional and mechanistic understanding of the GPCR family that binds large macromolecular ligands.
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Affiliation(s)
- Andra C Dumitru
- Université catholique de Louvain, Louvain Institute of Biomolecular Science and Technology, 1348, Louvain-la-Neuve, Belgium
| | - R N V Krishna Deepak
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Heng Liu
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Melanie Koehler
- Université catholique de Louvain, Louvain Institute of Biomolecular Science and Technology, 1348, Louvain-la-Neuve, Belgium
| | - Cheng Zhang
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
| | - Hao Fan
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore.
| | - David Alsteens
- Université catholique de Louvain, Louvain Institute of Biomolecular Science and Technology, 1348, Louvain-la-Neuve, Belgium.
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34
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Transport Cycle of Plasma Membrane Flippase ATP11C by Cryo-EM. Cell Rep 2020; 32:108208. [DOI: 10.1016/j.celrep.2020.108208] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/29/2020] [Accepted: 09/09/2020] [Indexed: 02/08/2023] Open
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35
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Current pivotal strategies leading a difficult target protein to a sample suitable for crystallographic analysis. Biochem Soc Trans 2020; 48:1661-1673. [PMID: 32677661 DOI: 10.1042/bst20200106] [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] [Received: 05/16/2020] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 12/15/2022]
Abstract
Crystallographic structural analysis is an essential method for the determination of protein structure. However, crystallization of a protein of interest is the most difficult process in the analysis. The process is often hampered during the sample preparation, including expression and purification. Even after a sample has been purified, not all candidate proteins crystallize. In this mini-review, the current methodologies used to overcome obstacles encountered during protein crystallization are sorted. Specifically, the strategy for an effective crystallization is compared with a pipeline where various expression hosts and constructs, purification and crystallization conditions, and crystallization chaperones as target-specific binder proteins are assessed by a precrystallization screening. These methodologies are also developed continuously to improve the process. The described methods are useful for sample preparation in crystallographic analysis and other structure determination techniques, such as cryo-electron microscopy.
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36
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Kwon M, Park K, Hyun K, Lee JH, Zhou L, Cho YW, Ge K, Skalnik DG, Muir TW, Kim J. H2B ubiquitylation enhances H3K4 methylation activities of human KMT2 family complexes. Nucleic Acids Res 2020; 48:5442-5456. [PMID: 32365172 PMCID: PMC7261165 DOI: 10.1093/nar/gkaa317] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 03/27/2020] [Accepted: 04/21/2020] [Indexed: 02/07/2023] Open
Abstract
In mammalian cells, distinct H3K4 methylation states are created by deposition of methyl groups by multiple complexes of histone lysine methyltransferase 2 (KMT2) family proteins. For comprehensive analyses that directly compare the catalytic properties of all six human KMT2 complexes, we employed a biochemically defined system reconstituted with recombinant KMT2 core complexes (KMT2CoreCs) containing minimal components required for nucleosomal H3K4 methylation activity. We found that each KMT2CoreC generates distinct states and different levels of H3K4 methylation, and except for MLL3 all are stimulated by H2Bub. Notably, SET1BCoreC exhibited the strongest H3K4 methylation activity and, to our surprise, did not require H2B ubiquitylation (H2Bub); in contrast, H2Bub was required for the H3K4me2/3 activity of the paralog SET1ACoreC. We also found that WDR5, RbBP5, ASH2L and DPY30 are required for efficient H3K4 methyltransferase activities of all KMT2CoreCs except MLL3, which could produce H3K4me1 in the absence of WDR5. Importantly, deletion of the PHD2 domain of CFP1 led to complete loss of the H3K4me2/3 activities of SET1A/BCoreCs in the presence of H2Bub, indicating a critical role for this domain in the H2Bub-stimulated H3K4 methylation. Collectively, our results suggest that each KMT2 complex methylates H3K4 through distinct mechanisms in which individual subunits differentially participate.
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Affiliation(s)
- Minjung Kwon
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
| | - Kihyun Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
| | - Kwangbeom Hyun
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
| | - Jeong-Heon Lee
- Biology Department, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Linjiao Zhou
- Department of Chemistry, Princeton University, Frick Laboratory, Princeton, NJ 08544, USA
| | - Young-Wook Cho
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kai Ge
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - David G Skalnik
- Biology Department, School of Science, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Tom W Muir
- Department of Chemistry, Princeton University, Frick Laboratory, Princeton, NJ 08544, USA
| | - Jaehoon Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon 34141, South Korea
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37
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Tsutsumi N, Mukherjee S, Waghray D, Janda CY, Jude KM, Miao Y, Burg JS, Aduri NG, Kossiakoff AA, Gati C, Garcia KC. Structure of human Frizzled5 by fiducial-assisted cryo-EM supports a heterodimeric mechanism of canonical Wnt signaling. eLife 2020; 9:e58464. [PMID: 32762848 PMCID: PMC7442489 DOI: 10.7554/elife.58464] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 08/06/2020] [Indexed: 01/19/2023] Open
Abstract
Frizzleds (Fzd) are the primary receptors for Wnt morphogens, which are essential regulators of stem cell biology, yet the structural basis of Wnt signaling through Fzd remains poorly understood. Here we report the structure of an unliganded human Fzd5 determined by single-particle cryo-EM at 3.7 Å resolution, with the aid of an antibody chaperone acting as a fiducial marker. We also analyzed the topology of low-resolution XWnt8/Fzd5 complex particles, which revealed extreme flexibility between the Wnt/Fzd-CRD and the Fzd-TM regions. Analysis of Wnt/β-catenin signaling in response to Wnt3a versus a 'surrogate agonist' that cross-links Fzd to LRP6, revealed identical structure-activity relationships. Thus, canonical Wnt/β-catenin signaling appears to be principally reliant on ligand-induced Fzd/LRP6 heterodimerization, versus the allosteric mechanisms seen in structurally analogous class A G protein-coupled receptors, and Smoothened. These findings deepen our mechanistic understanding of Wnt signal transduction, and have implications for harnessing Wnt agonism in regenerative medicine.
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Affiliation(s)
- Naotaka Tsutsumi
- Department of Molecular and Cellular Physiology, Stanford University School of MedicineStanfordUnited States
- Department of Structural Biology, Stanford University School of MedicineStanfordUnited States
- Howard Hughes Medical Institute, Stanford University School of MedicineStanfordUnited States
| | - Somnath Mukherjee
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
| | - Deepa Waghray
- Department of Molecular and Cellular Physiology, Stanford University School of MedicineStanfordUnited States
| | - Claudia Y Janda
- Department of Molecular and Cellular Physiology, Stanford University School of MedicineStanfordUnited States
- Department of Structural Biology, Stanford University School of MedicineStanfordUnited States
- Princess Máxima Center for Pediatric OncologyUtrechtNetherlands
| | - Kevin M Jude
- Department of Molecular and Cellular Physiology, Stanford University School of MedicineStanfordUnited States
- Department of Structural Biology, Stanford University School of MedicineStanfordUnited States
- Howard Hughes Medical Institute, Stanford University School of MedicineStanfordUnited States
| | - Yi Miao
- Department of Molecular and Cellular Physiology, Stanford University School of MedicineStanfordUnited States
- Department of Structural Biology, Stanford University School of MedicineStanfordUnited States
| | - John S Burg
- Department of Molecular and Cellular Physiology, Stanford University School of MedicineStanfordUnited States
- Department of Structural Biology, Stanford University School of MedicineStanfordUnited States
| | - Nanda Gowtham Aduri
- Department of Structural Biology, Stanford University School of MedicineStanfordUnited States
- SLAC National Accelerator Laboratory, Bioscience DivisionMenlo ParkUnited States
| | - Anthony A Kossiakoff
- Department of Biochemistry and Molecular Biology, The University of ChicagoChicagoUnited States
| | - Cornelius Gati
- Department of Structural Biology, Stanford University School of MedicineStanfordUnited States
- SLAC National Accelerator Laboratory, Bioscience DivisionMenlo ParkUnited States
| | - K Christopher Garcia
- Department of Molecular and Cellular Physiology, Stanford University School of MedicineStanfordUnited States
- Department of Structural Biology, Stanford University School of MedicineStanfordUnited States
- Howard Hughes Medical Institute, Stanford University School of MedicineStanfordUnited States
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38
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The structure of lipid nanodisc-reconstituted TRPV3 reveals the gating mechanism. Nat Struct Mol Biol 2020; 27:645-652. [PMID: 32572254 DOI: 10.1038/s41594-020-0439-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 04/24/2020] [Indexed: 12/17/2022]
Abstract
Transient receptor potential vanilloid subfamily member 3 (TRPV3) is a temperature-sensitive cation channel. Previous cryo-EM analyses of TRPV3 in detergent micelles or amphipol proposed that the lower gate opens by α-to-π helical transitions of the nearby S6 helix. However, it remains unclear how physiological lipids are involved in the TRPV3 activation. Here we determined the apo state structure of mouse (Mus musculus) TRPV3 in a lipid nanodisc at 3.3 Å resolution. The structure revealed that lipids bound to the pore domain stabilize the selectivity filter in the narrow state, suggesting that the selectivity filter of TRPV3 affects cation permeation. When the lower gate is closed in nanodisc-reconstituted TRPV3, the S6 helix adopts the π-helical conformation without agonist- or heat-sensitization, potentially stabilized by putative intra-subunit hydrogen bonds and lipid binding. Our findings provide insights into the lipid-associated gating mechanism of TRPV3.
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39
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Nakanishi H, Irie K, Segawa K, Hasegawa K, Fujiyoshi Y, Nagata S, Abe K. Crystal structure of a human plasma membrane phospholipid flippase. J Biol Chem 2020; 295:10180-10194. [PMID: 32493773 DOI: 10.1074/jbc.ra120.014144] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/29/2020] [Indexed: 12/27/2022] Open
Abstract
ATP11C, a member of the P4-ATPase flippase, translocates phosphatidylserine from the outer to the inner plasma membrane leaflet, and maintains the asymmetric distribution of phosphatidylserine in the living cell. We present the crystal structures of a human plasma membrane flippase, ATP11C-CDC50A complex, in a stabilized E2P conformation. The structure revealed a deep longitudinal crevice along transmembrane helices continuing from the cell surface to the phospholipid occlusion site in the middle of the membrane. We observed that the extension of the crevice on the exoplasmic side is open, and the complex is therefore in an outward-open E2P state, similar to a recently reported cryo-EM structure of yeast flippase Drs2p-Cdc50p complex. We noted extra densities, most likely bound phosphatidylserines, in the crevice and in its extension to the extracellular side. One was close to the phosphatidylserine occlusion site as previously reported for the human ATP8A1-CDC50A complex, and the other in a cavity at the surface of the exoplasmic leaflet of the bilayer. Substitutions in either of the binding sites or along the path between them impaired specific ATPase and transport activities. These results provide evidence that the observed crevice is the conduit along that phosphatidylserine traverses from the outer leaflet to its occlusion site in the membrane and suggest that the exoplasmic cavity is important for phospholipid recognition. They also yield insights into how phosphatidylserine is incorporated from the outer leaflet of the plasma membrane into the transmembrane.
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Affiliation(s)
- Hanayo Nakanishi
- Cellular and Structural Physiology Institute, Nagoya University, Nagoya, Japan
| | - Katsumasa Irie
- Cellular and Structural Physiology Institute, Nagoya University, Nagoya, Japan.,Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan
| | - Katsumori Segawa
- WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Kazuya Hasegawa
- Japan Synchrotron Radiation Research Institute, 1-1-1 Kouto, Sayo, Japan
| | - Yoshinori Fujiyoshi
- TMDU Advanced Research Institute, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, Japan.,CeSPIA Inc, 2-1-1, Otemachi, Chiyoda, Tokyo, Japan
| | - Shigekazu Nagata
- WPI Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Kazuhiro Abe
- Cellular and Structural Physiology Institute, Nagoya University, Nagoya, Japan .,Graduate School of Pharmaceutical Sciences, Nagoya University, Nagoya, Japan
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40
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Errey JC, Fiez-Vandal C. Production of membrane proteins in industry: The example of GPCRs. Protein Expr Purif 2020; 169:105569. [DOI: 10.1016/j.pep.2020.105569] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 01/07/2020] [Accepted: 01/12/2020] [Indexed: 01/08/2023]
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41
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Kuo YC, Chen H, Shang G, Uchikawa E, Tian H, Bai XC, Zhang X. Cryo-EM structure of the PlexinC1/A39R complex reveals inter-domain interactions critical for ligand-induced activation. Nat Commun 2020; 11:1953. [PMID: 32327662 PMCID: PMC7181871 DOI: 10.1038/s41467-020-15862-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 04/01/2020] [Indexed: 11/09/2022] Open
Abstract
Plexins are receptors for semaphorins that transduce signals for regulating neuronal development and other processes. Plexins are single-pass transmembrane proteins with multiple domains in both the extracellular and intracellular regions. Semaphorin activates plexin by binding to its extracellular N-terminal Sema domain, inducing the active dimer of the plexin intracellular region. The mechanism underlying this activation process of plexin is incompletely understood. We present cryo-electron microscopic structure of full-length human PlexinC1 in complex with the viral semaphorin mimic A39R. The structure shows that A39R induces a specific dimer of PlexinC1 where the membrane-proximal domains from the two PlexinC1 protomers are placed close to each other, poised to promote the active dimer of the intracellular region. This configuration is imposed by a distinct conformation of the PlexinC1 extracellular region, stabilized by inter-domain interactions among the Sema and membrane-proximal domains. Our mutational analyses support the critical role of this conformation in PlexinC1 activation. Plexins are the receptors for the guidance molecules semaphorins and regulate immunity and the development of the nervous and cardiovascular systems. Here authors present a structure of full-length human PlexinC1 in complex with its ligand A39R, which reveals how inter-domain interactions couple extracellular ligand binding to receptor activation and signaling.
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Affiliation(s)
- Yi-Chun Kuo
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Hua Chen
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Guijun Shang
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Emiko Uchikawa
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Hui Tian
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Xiao-Chen Bai
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA. .,Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, USA.
| | - Xuewu Zhang
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA. .,Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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42
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Progress in nicotinic receptor structural biology. Neuropharmacology 2020; 171:108086. [PMID: 32272141 DOI: 10.1016/j.neuropharm.2020.108086] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 03/31/2020] [Indexed: 02/07/2023]
Abstract
Here we begin by briefly reviewing landmark structural studies on the nicotinic acetylcholine receptor. We highlight challenges that had to be overcome to push through resolution barriers, then focus on what has been gleaned in the past few years from crystallographic and single particle cryo-EM studies of different nicotinic receptor subunit assemblies and ligand complexes. We discuss insights into ligand recognition, ion permeation, and allosteric gating. We then highlight some foundational aspects of nicotinic receptor structural biology that remain unresolved and are areas ripe for future exploration. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.
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43
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Haffke M, Duckely M, Bergsdorf C, Jaakola VP, Shrestha B. Development of a biochemical and biophysical suite for integral membrane protein targets: A review. Protein Expr Purif 2020; 167:105545. [DOI: 10.1016/j.pep.2019.105545] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 11/18/2019] [Accepted: 11/24/2019] [Indexed: 12/11/2022]
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44
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Wilson SC, White KI, Zhou Q, Pfuetzner RA, Choi UB, Südhof TC, Brunger AT. Structures of neurexophilin-neurexin complexes reveal a regulatory mechanism of alternative splicing. EMBO J 2019; 38:e101603. [PMID: 31566781 PMCID: PMC6856630 DOI: 10.15252/embj.2019101603] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 08/29/2019] [Accepted: 08/30/2019] [Indexed: 01/09/2023] Open
Abstract
Neurexins are presynaptic, cell-adhesion molecules that specify the functional properties of synapses via interactions with trans-synaptic ligands. Neurexins are extensively alternatively spliced at six canonical sites that regulate multifarious ligand interactions, but the structural mechanisms underlying alternative splicing-dependent neurexin regulation are largely unknown. Here, we determined high-resolution structures of the complex of neurexophilin-1 and the second laminin/neurexin/sex-hormone-binding globulin domain (LNS2) of neurexin-1 and examined how alternative splicing at splice site #2 (SS2) regulates the complex. Our data reveal a unique, extensive, neurexophilin-neurexin binding interface that extends the jelly-roll β-sandwich of LNS2 of neurexin-1 into neurexophilin-1. The SS2A insert of LNS2 augments this interface, increasing the binding affinity of LNS2 for neurexophilin-1. Taken together, our data reveal an unexpected architecture of neurexophilin-neurexin complexes that accounts for the modulation of binding by alternative splicing, which in turn regulates the competition of neurexophilin for neurexin binding with other ligands.
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Affiliation(s)
- Steven C Wilson
- Department of Molecular and Cellular PhysiologyStanford UniversityStanfordCAUSA
| | - K Ian White
- Department of Molecular and Cellular PhysiologyStanford UniversityStanfordCAUSA
| | - Qiangjun Zhou
- Department of Molecular and Cellular PhysiologyStanford UniversityStanfordCAUSA
| | - Richard A Pfuetzner
- Department of Molecular and Cellular PhysiologyStanford UniversityStanfordCAUSA
| | - Ucheor B Choi
- Department of Molecular and Cellular PhysiologyStanford UniversityStanfordCAUSA
| | - Thomas C Südhof
- Department of Molecular and Cellular PhysiologyStanford UniversityStanfordCAUSA
- Howard Hughes Medical InstituteStanford UniversityStanfordCAUSA
| | - Axel T Brunger
- Department of Molecular and Cellular PhysiologyStanford UniversityStanfordCAUSA
- Howard Hughes Medical InstituteStanford UniversityStanfordCAUSA
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45
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Nielsen AK, Möller IR, Wang Y, Rasmussen SGF, Lindorff-Larsen K, Rand KD, Loland CJ. Substrate-induced conformational dynamics of the dopamine transporter. Nat Commun 2019; 10:2714. [PMID: 31221956 PMCID: PMC6586795 DOI: 10.1038/s41467-019-10449-w] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 05/09/2019] [Indexed: 02/02/2023] Open
Abstract
The dopamine transporter is a member of the neurotransmitter:sodium symporters (NSSs), which are responsible for termination of neurotransmission through Na+-driven reuptake of neurotransmitter from the extracellular space. Experimental evidence elucidating the coordinated conformational rearrangements related to the transport mechanism has so far been limited. Here we probe the global Na+- and dopamine-induced conformational dynamics of the wild-type Drosophila melanogaster dopamine transporter using hydrogen-deuterium exchange mass spectrometry. We identify Na+- and dopamine-induced changes in specific regions of the transporter, suggesting their involvement in protein conformational transitions. Furthermore, we detect ligand-dependent slow cooperative fluctuations of helical stretches in several domains of the transporter, which could be a molecular mechanism that assists in the transporter function. Our results provide a framework for understanding the molecular mechanism underlying the function of NSSs by revealing detailed insight into the state-dependent conformational changes associated with the alternating access model of the dopamine transporter.
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Affiliation(s)
- Anne Kathrine Nielsen
- Laboratory for Membrane Protein Dynamics, Department of Neuroscience, University of Copenhagen, 2200, Copenhagen N, Denmark
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, 2100, Copenhagen Ø, Denmark
| | - Ingvar R Möller
- Laboratory for Membrane Protein Dynamics, Department of Neuroscience, University of Copenhagen, 2200, Copenhagen N, Denmark
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, 2100, Copenhagen Ø, Denmark
| | - Yong Wang
- Structural Biology and NMR Laboratory, Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, 2200, Copenhagen N, Denmark
| | - Søren G F Rasmussen
- Department of Neuroscience, University of Copenhagen, 2200, Copenhagen N, Denmark
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory, Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, 2200, Copenhagen N, Denmark
| | - Kasper D Rand
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, 2100, Copenhagen Ø, Denmark.
| | - Claus J Loland
- Laboratory for Membrane Protein Dynamics, Department of Neuroscience, University of Copenhagen, 2200, Copenhagen N, Denmark.
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46
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Pearce KH, Overton LK, Gampe RT, Barrett GB, Taylor JD, McKee DD, Campobasso N, Nolte RT, Reid RA. BacMam production and crystal structure of nonglycosylated apo human furin at 1.89 Å resolution. Acta Crystallogr F Struct Biol Commun 2019; 75:239-245. [PMID: 30950824 PMCID: PMC6450522 DOI: 10.1107/s2053230x19001419] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 01/25/2019] [Indexed: 02/06/2023] Open
Abstract
Furin, also called proprotein convertase subtilisin/kexin 3 (PCSK3), is a calcium-dependent serine endoprotease that processes a wide variety of proproteins involved in cell function and homeostasis. Dysregulation of furin has been implicated in numerous disease states, including cancer and fibrosis. Mammalian cell expression of the furin ectodomain typically produces a highly glycosylated, heterogeneous protein, which can make crystallographic studies difficult. Here, the expression and purification of nonglycosylated human furin using the BacMam technology and site-directed mutagenesis of the glycosylation sites is reported. Nonglycosylated furin produced using this system retains full proteolytic activity indistinguishable from that of the glycosylated protein. Importantly, the nonglycosylated furin protein reliably forms extremely durable apo crystals that diffract to high resolution. These crystals can be soaked with a wide variety of inhibitors to enable a structure-guided drug-discovery campaign.
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Affiliation(s)
- Kenneth H. Pearce
- Eshelman School of Pharmacy, Division of Chemical Biology and Medicinal Chemistry, Center for Integrative Chemical Biology and Drug Discovery, University of North Carolina at Chapel Hill, 125 Mason Farm Road, Chapel Hill, NC 27599, USA
| | - Laurie K. Overton
- Platform Technology and Science, Department of Protein Cellular and Structural Sciences, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, PA 19426, USA
| | - Robert T. Gampe
- Platform Technology and Science, Department of Protein Cellular and Structural Sciences, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, PA 19426, USA
| | - George B. Barrett
- Platform Technology and Science, Department of Protein Cellular and Structural Sciences, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, PA 19426, USA
| | - J. David Taylor
- Platform Technology and Science, Department of Protein Cellular and Structural Sciences, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, PA 19426, USA
| | - David D. McKee
- Platform Technology and Science, Department of Protein Cellular and Structural Sciences, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, PA 19426, USA
| | - Nino Campobasso
- Platform Technology and Science, Department of Protein Cellular and Structural Sciences, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, PA 19426, USA
| | - Robert T. Nolte
- Platform Technology and Science, Department of Protein Cellular and Structural Sciences, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, PA 19426, USA
| | - Robert A. Reid
- Platform Technology and Science, Department of Protein Cellular and Structural Sciences, GlaxoSmithKline, 1250 South Collegeville Road, Collegeville, PA 19426, USA
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47
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Cryo-EM structures of STING reveal its mechanism of activation by cyclic GMP-AMP. Nature 2019; 567:389-393. [PMID: 30842659 DOI: 10.1038/s41586-019-0998-5] [Citation(s) in RCA: 379] [Impact Index Per Article: 75.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 02/12/2019] [Indexed: 12/25/2022]
Abstract
Infections by pathogens that contain DNA trigger the production of type-I interferons and inflammatory cytokines through cyclic GMP-AMP synthase, which produces 2'3'-cyclic GMP-AMP (cGAMP) that binds to and activates stimulator of interferon genes (STING; also known as TMEM173, MITA, ERIS and MPYS)1-8. STING is an endoplasmic-reticulum membrane protein that contains four transmembrane helices followed by a cytoplasmic ligand-binding and signalling domain9-13. The cytoplasmic domain of STING forms a dimer, which undergoes a conformational change upon binding to cGAMP9,14. However, it remains unclear how this conformational change leads to STING activation. Here we present cryo-electron microscopy structures of full-length STING from human and chicken in the inactive dimeric state (about 80 kDa in size), as well as cGAMP-bound chicken STING in both the dimeric and tetrameric states. The structures show that the transmembrane and cytoplasmic regions interact to form an integrated, domain-swapped dimeric assembly. Closure of the ligand-binding domain, induced by cGAMP, leads to a 180° rotation of the ligand-binding domain relative to the transmembrane domain. This rotation is coupled to a conformational change in a loop on the side of the ligand-binding-domain dimer, which leads to the formation of the STING tetramer and higher-order oligomers through side-by-side packing. This model of STING oligomerization and activation is supported by our structure-based mutational analyses.
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48
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Lacabanne D, Fogeron ML, Wiegand T, Cadalbert R, Meier BH, Böckmann A. Protein sample preparation for solid-state NMR investigations. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 110:20-33. [PMID: 30803692 DOI: 10.1016/j.pnmrs.2019.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/11/2019] [Accepted: 01/12/2019] [Indexed: 06/09/2023]
Abstract
Preparation of a protein sample for solid-state NMR is in many aspects similar to solution-state NMR approaches, mainly with respect to the need for stable isotope labeling. But the possibility of using solid-state NMR to investigate membrane proteins in (native) lipids adds the important requirement of adapted membrane-reconstitution schemes. Also, dynamic nuclear polarization and paramagnetic NMR in solids need specific schemes using metal ions and radicals. Sample sedimentation has enabled structural investigations of objects inaccessible to other structural techniques, but rotor filling using sedimentation has become increasingly complex with smaller and smaller rotors, as needed for higher and higher magic-angle spinning (MAS) frequencies. Furthermore, solid-state NMR can investigate very large proteins and their complexes without the concomitant increase in line widths, motivating the use of selective labeling and unlabeling strategies, as well as segmental labeling, to decongest spectra. The possibility of investigating sub-milligram amounts of protein today using advanced fast MAS techniques enables alternative protein synthesis schemes such as cell-free expression. Here we review these specific aspects of solid-state NMR sample preparation.
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Affiliation(s)
- Denis Lacabanne
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, 69367 Lyon, France; Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Marie-Laure Fogeron
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, 69367 Lyon, France
| | - Thomas Wiegand
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | | | - Beat H Meier
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland.
| | - Anja Böckmann
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, 69367 Lyon, France.
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49
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Dissecting diverse functions of NMDA receptors by structural biology. Curr Opin Struct Biol 2019; 54:34-42. [PMID: 30703613 DOI: 10.1016/j.sbi.2018.12.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/09/2018] [Accepted: 12/20/2018] [Indexed: 12/18/2022]
Abstract
N-Methyl-d-aspartate receptors (NMDARs) are glutamate-gated ion channels, which are critically involved in brain development, learning and memory, cognition, as well as a number of neurological diseases and disorders. Structural biology of NMDARs has been challenging due to technical difficulties associated with assembling a number of different membrane protein subunits. Here, we review historical X-ray crystallographic studies on isolated extracellular domains, which are still the most effective mean to delineate compound binding modes, as well as the most recent studies using electron cryo-microscopy (cryo-EM). A number of NMDAR structures accumulated over the past 15 years provide insights into the hetero-tetrameric assembly pattern, pharmacological specificities elicited by subtypes and alternative splicing, and potential patterns of conformational dynamics; however, many more important unanswered questions remain.
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50
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Rana MS, Wang X, Banerjee A. An Improved Strategy for Fluorescent Tagging of Membrane Proteins for Overexpression and Purification in Mammalian Cells. Biochemistry 2018; 57:6741-6751. [PMID: 30481009 PMCID: PMC7266526 DOI: 10.1021/acs.biochem.8b01070] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An essential prerequisite for in vitro biochemical or structural studies is a construct that is amenable to high level expression and purification and is biochemically "well-behaved". In the field of membrane protein research, the use of green fluorescent protein (GFP) to monitor and optimize the heterologous expression in different hosts has radically changed the ease of streamlining and multiplexing the testing of a large number of candidate constructs. This is achieved by genetically fusing the fluorescent proteins to the N- or C-terminus of the proteins of interest to act as reporters which can then be followed by methods such as microscopy, spectroscopy, or in-gel fluorescence. Nonetheless, a systematic study on the effect of GFP and its spectral variants on the expression and yields of recombinant membrane proteins is lacking. In this study, we genetically appended four common fluorescent protein tags, namely, mEGFP, mVenus, mCerulean, and mCherry, to the N- or C-terminus of different membrane proteins and assessed their expression in mammalian cells by fluorescence-detection size exclusion chromatography (FSEC) and protein purification. We find that, of the four fluorescent proteins, tagging with mVenus systematically results in higher expression levels that translates to higher yields in preparative purifications, thus making a case for switching to this yellow spectral variant as a better fusion tag.
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Affiliation(s)
- Mitra S. Rana
- Cell Biology and Neurobiology Branch, National Institutes of Child Health and Human Development, National Institutes of Health, Bethesda, MD-20892
| | - Xiyu Wang
- Cell Biology and Neurobiology Branch, National Institutes of Child Health and Human Development, National Institutes of Health, Bethesda, MD-20892
| | - Anirban Banerjee
- Cell Biology and Neurobiology Branch, National Institutes of Child Health and Human Development, National Institutes of Health, Bethesda, MD-20892
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