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Matsell E, Andersen JP, Molday RS. Functional and in silico analysis of ATP8A2 and other P4-ATPase variants associated with human genetic diseases. Dis Model Mech 2024; 17:dmm050546. [PMID: 38436085 PMCID: PMC11073571 DOI: 10.1242/dmm.050546] [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: 10/10/2023] [Accepted: 02/21/2024] [Indexed: 03/05/2024] Open
Abstract
P4-ATPases flip lipids from the exoplasmic to cytoplasmic leaflet of cell membranes, a property crucial for many biological processes. Mutations in P4-ATPases are associated with severe inherited and complex human disorders. We determined the expression, localization and ATPase activity of four variants of ATP8A2, the P4-ATPase associated with the neurodevelopmental disorder known as cerebellar ataxia, impaired intellectual development and disequilibrium syndrome 4 (CAMRQ4). Two variants, G447R and A772P, harboring mutations in catalytic domains, expressed at low levels and mislocalized in cells. In contrast, the E459Q variant in a flexible loop displayed wild-type expression levels, Golgi-endosome localization and ATPase activity. The R1147W variant expressed at 50% of wild-type levels but showed normal localization and activity. These results indicate that the G447R and A772P mutations cause CAMRQ4 through protein misfolding. The E459Q mutation is unlikely to be causative, whereas the R1147W may display a milder disease phenotype. Using various programs that predict protein stability, we show that there is a good correlation between the experimental expression of the variants and in silico stability assessments, suggesting that such analysis is useful in identifying protein misfolding disease-associated variants.
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Affiliation(s)
- Eli Matsell
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | | | - Robert S. Molday
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
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2
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Hong JD, Salom D, Choi EH, Du SW, Tworak A, Smidak R, Gao F, Solano YJ, Zhang J, Kiser PD, Palczewski K. Retinylidene chromophore hydrolysis from mammalian visual and non-visual opsins. J Biol Chem 2024; 300:105678. [PMID: 38272218 PMCID: PMC10877631 DOI: 10.1016/j.jbc.2024.105678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 01/06/2024] [Accepted: 01/13/2024] [Indexed: 01/27/2024] Open
Abstract
Rhodopsin (Rho) and cone opsins are essential for detection of light. They respond via photoisomerization, converting their Schiff-base-adducted 11-cis-retinylidene chromophores to the all-trans configuration, eliciting conformational changes to activate opsin signaling. Subsequent Schiff-base hydrolysis releases all-trans-retinal, initiating two important cycles that maintain continuous vision-the Rho photocycle and visual cycle pathway. Schiff-base hydrolysis has been thoroughly studied with photoactivated Rho but not with cone opsins. Using established methodology, we directly measured the formation of Schiff-base between retinal chromophores with mammalian visual and nonvisual opsins of the eye. Next, we determined the rate of light-induced chromophore hydrolysis. We found that retinal hydrolysis from photoactivated cone opsins was markedly faster than from photoactivated Rho. Bovine retinal G protein-coupled receptor (bRGR) displayed rapid hydrolysis of its 11-cis-retinylidene photoproduct to quickly supply 11-cis-retinal and re-bind all-trans-retinal. Hydrolysis within bRGR in native retinal pigment epithelium microsomal membranes was >6-times faster than that of bRGR purified in detergent micelles. N-terminal-targeted antibodies significantly slowed bRGR hydrolysis, while C-terminal antibodies had no effect. Our study highlights the much faster photocycle of cone opsins relative to Rho and the crucial role of RGR in chromophore recycling in daylight. By contrast, in our experimental conditions, bovine peropsin did not form pigment in the presence of all-trans-retinal nor with any mono-cis retinal isomers, leaving uncertain the role of this opsin as a light sensor.
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Affiliation(s)
- John D Hong
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA; Department of Chemistry, University of California Irvine, Irvine, California, USA
| | - David Salom
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA.
| | - Elliot H Choi
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA
| | - Samuel W Du
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA; Department of Physiology and Biophysics, University of California Irvine, Irvine, California, USA
| | - Aleksander Tworak
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA
| | - Roman Smidak
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA
| | - Fangyuan Gao
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA
| | - Yasmeen J Solano
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA; Department of Physiology and Biophysics, University of California Irvine, Irvine, California, USA
| | - Jianye Zhang
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA
| | - Philip D Kiser
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA; Department of Physiology and Biophysics, University of California Irvine, Irvine, California, USA; Department of Clinical Pharmacy Practice, University of California Irvine, Irvine, California, USA; Research Service, VA Long Beach Healthcare System, Long Beach, California, USA
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, California, USA; Department of Chemistry, University of California Irvine, Irvine, California, USA; Department of Physiology and Biophysics, University of California Irvine, Irvine, California, USA; Department of Molecular Biology and Biochemistry, University of California Irvine, Irvine, California, USA.
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3
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Shumate AD, Farrens DL. A rapid, tag-free way to purify functional GPCRs. J Biol Chem 2024; 300:105558. [PMID: 38097184 PMCID: PMC10820827 DOI: 10.1016/j.jbc.2023.105558] [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: 05/12/2023] [Revised: 12/01/2023] [Accepted: 12/05/2023] [Indexed: 01/14/2024] Open
Abstract
G protein-coupled receptors (GPCRs) play diverse signaling roles and represent major pharmaceutical targets. Consequently, they are the focus of intense study, and numerous advances have been made in their handling and analysis. However, a universal way to purify GPCRs has remained elusive, in part because of their inherent instability when isolated from cells. To address this, we have developed a general, rapid, and tag-free way to purify GPCRs. The method uses short peptide analogs of the Gα subunit C terminus (Gα-CT) that are attached to chromatography beads (Gα-CT resin). Because the Gα-CT peptides bind active GPCRs with high affinity, the Gα-CT resin selectively purifies only active functional receptors. We use this method to purify both rhodopsin and the β2-adrenergic receptor and show they can be purified in either active conformations or inactive conformations, simply by varying elution conditions. While simple in concept-leveraging the conserved GPCR-Gα-CT binding interaction for the purpose of GPCR purification-we think this approach holds excellent potential to isolate functional receptors for a myriad of uses, from structural biology to proteomics.
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Affiliation(s)
- Anthony D Shumate
- Department of Chemical Biology and Physiology, Oregon Health and Science University, Portland, Oregon, USA
| | - David L Farrens
- Department of Chemical Biology and Physiology, Oregon Health and Science University, Portland, Oregon, USA.
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4
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Gu S, Huang M, Handel TM. On-bead purification and nanodisc reconstitution of human chemokine receptor complexes for structural and biophysical studies. STAR Protoc 2023; 4:102460. [PMID: 37516969 PMCID: PMC10407235 DOI: 10.1016/j.xpro.2023.102460] [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: 04/12/2023] [Revised: 06/02/2023] [Accepted: 06/23/2023] [Indexed: 08/01/2023] Open
Abstract
Chemokine receptors, a subfamily of G-protein-coupled receptors (GPCRs), are responsible for cell migration during physiological processes as well as in diseases like inflammation and cancers. Here, we present a protocol for solubilizing, purifying, and reconstituting complexes of chemokine receptors with their ligands in "nanodiscs," soluble lipid bilayers that mimic the native environment of membrane receptors. The protocol yields chemokine receptor complexes with sufficient purity and yield for structural and biophysical studies and should be applicable to other GPCRs.
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Affiliation(s)
- Siyi Gu
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, San Diego, CA 92093, USA.
| | - Mian Huang
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, San Diego, CA 92093, USA
| | - Tracy M Handel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, San Diego, CA 92093, USA.
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5
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Chang TH, Hsieh FL, Gu X, Smallwood PM, Kavran JM, Gabelli SB, Nathans J. Structural insights into plasmalemma vesicle-associated protein (PLVAP): Implications for vascular endothelial diaphragms and fenestrae. Proc Natl Acad Sci U S A 2023; 120:e2221103120. [PMID: 36996108 PMCID: PMC10083539 DOI: 10.1073/pnas.2221103120] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 02/20/2023] [Indexed: 03/31/2023] Open
Abstract
In many organs, small openings across capillary endothelial cells (ECs) allow the diffusion of low-molecular weight compounds and small proteins between the blood and tissue spaces. These openings contain a diaphragm composed of radially arranged fibers, and current evidence suggests that a single-span type II transmembrane protein, plasmalemma vesicle-associated protein-1 (PLVAP), constitutes these fibers. Here, we present the three-dimensional crystal structure of an 89-amino acid segment of the PLVAP extracellular domain (ECD) and show that it adopts a parallel dimeric alpha-helical coiled-coil configuration with five interchain disulfide bonds. The structure was solved using single-wavelength anomalous diffraction from sulfur-containing residues (sulfur SAD) to generate phase information. Biochemical and circular dichroism (CD) experiments show that a second PLVAP ECD segment also has a parallel dimeric alpha-helical configuration-presumably a coiled coil-held together with interchain disulfide bonds. Overall, ~2/3 of the ~390 amino acids within the PLVAP ECD adopt a helical configuration, as determined by CD. We also determined the sequence and epitope of MECA-32, an anti-PLVAP antibody. Taken together, these data lend strong support to the model of capillary diaphragms formulated by Tse and Stan in which approximately ten PLVAP dimers are arranged within each 60- to 80-nm-diameter opening like the spokes of a bicycle wheel. Passage of molecules through the wedge-shaped pores is presumably determined both by the length of PLVAP-i.e., the long dimension of the pore-and by the chemical properties of amino acid side chains and N-linked glycans on the solvent-accessible faces of PLVAP.
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Affiliation(s)
- Tao-Hsin Chang
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD21205
- HHMI, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Fu-Lien Hsieh
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD21205
- HHMI, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Xiaowu Gu
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD21205
- HHMI, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Philip M. Smallwood
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD21205
- HHMI, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Jennifer M. Kavran
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD21205
| | - Sandra B. Gabelli
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD21205
| | - Jeremy Nathans
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD21205
- HHMI, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD21205
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD21205
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6
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Le LTM, Thompson JR, Dehghani‐Ghahnaviyeh S, Pant S, Dang PX, French JB, Kanikeyo T, Tajkhorshid E, Alam A. Cryo-EM structures of human ABCA7 provide insights into its phospholipid translocation mechanisms. EMBO J 2023; 42:e111065. [PMID: 36484366 PMCID: PMC9890230 DOI: 10.15252/embj.2022111065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 11/07/2022] [Accepted: 11/10/2022] [Indexed: 12/13/2022] Open
Abstract
Phospholipid extrusion by ABC subfamily A (ABCA) exporters is central to cellular physiology, although the specifics of the underlying substrate interactions and transport mechanisms remain poorly resolved at the molecular level. Here we report cryo-EM structures of lipid-embedded human ABCA7 in an open state and in a nucleotide-bound, closed state at resolutions between 3.6 and 4.0 Å. The former reveals an ordered patch of bilayer lipids traversing the transmembrane domain (TMD), while the latter reveals a lipid-free, closed TMD with a small extracellular opening. These structures offer a structural framework for both substrate entry and exit from the ABCA7 TMD and highlight conserved rigid-body motions that underlie the associated conformational transitions. Combined with functional analysis and molecular dynamics (MD) simulations, our data also shed light on lipid partitioning into the ABCA7 TMD and localized membrane perturbations that underlie ABCA7 function and have broader implications for other ABCA family transporters.
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Affiliation(s)
- Le Thi My Le
- The Hormel InstituteUniversity of MinnesotaAustinMNUSA
| | | | - Sepehr Dehghani‐Ghahnaviyeh
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative BiologyUniversity of Illinois at Urbana‐ChampaignUrbanaILUSA
| | - Shashank Pant
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative BiologyUniversity of Illinois at Urbana‐ChampaignUrbanaILUSA
- Present address:
Loxo Oncology at LillyLouisvilleCOUSA
| | | | | | | | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, and Center for Biophysics and Quantitative BiologyUniversity of Illinois at Urbana‐ChampaignUrbanaILUSA
| | - Amer Alam
- The Hormel InstituteUniversity of MinnesotaAustinMNUSA
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7
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Mekhail K, Lee M, Sugiyama M, Astori A, St-Germain J, Latreille E, Khosraviani N, Wei K, Li Z, Rini J, Lee WL, Antonescu C, Raught B, Fairn GD. Fatty Acid Synthase inhibitor TVB-3166 prevents S-acylation of the Spike protein of human coronaviruses. J Lipid Res 2022; 63:100256. [PMID: 35921881 PMCID: PMC9339154 DOI: 10.1016/j.jlr.2022.100256] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/08/2022] [Accepted: 07/09/2022] [Indexed: 11/24/2022] Open
Abstract
The spike protein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other coronaviruses mediates host cell entry and is S-acylated on multiple phylogenetically conserved cysteine residues. Multiple protein acyltransferase enzymes have been reported to post-translationally modify spike proteins; however, strategies to exploit this modification are lacking. Using resin-assisted capture MS, we demonstrate that the spike protein is S-acylated in SARS-CoV-2-infected human and monkey epithelial cells. We further show that increased abundance of the acyltransferase ZDHHC5 associates with increased S-acylation of the spike protein, whereas ZDHHC5 knockout cells had a 40% reduction in the incorporation of an alkynyl-palmitate using click chemistry detection. We also found that the S-acylation of the spike protein is not limited to palmitate, as clickable versions of myristate and stearate were also labelled the protein. Yet, we observed that ZDHHC5 was only modified when incubated with alkyne-palmitate, suggesting it has specificity for this acyl-CoA, and that other ZDHHC enzymes may use additional fatty acids to modify the spike protein. Since multiple ZDHHC isoforms may modify the spike protein, we also examined the ability of the FASN inhibitor TVB-3166 to prevent S-acylation of the spike proteins of SARS-CoV-2 and human CoV-229E. We show that treating cells with TVB-3166 inhibited S-acylation of expressed spike proteins and attenuated the ability of SARS-CoV-2 and human CoV-229E to spread in vitro. Our findings further substantiate the necessity of CoV spike protein S-acylation and demonstrate that de novo fatty acid synthesis is critical for the proper S-acylation of the spike protein.
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Affiliation(s)
- Katrina Mekhail
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada
| | - Minhyoung Lee
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada
| | - Michael Sugiyama
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
| | - Audrey Astori
- Princess Margaret Cancer Centre, University Health Network, Ontario, Canada
| | | | - Elyse Latreille
- Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Negar Khosraviani
- Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada
| | - Kuiru Wei
- Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada
| | - Zhijie Li
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - James Rini
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Department of Molecular Genetics, University of Toronto, Ontario, Canada
| | - Warren L Lee
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada; Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Costin Antonescu
- Department of Chemistry and Biology, Ryerson University, Toronto, Ontario, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, University Health Network, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Ontario, Canada
| | - Gregory D Fairn
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada; Keenan Research Centre, St. Michael's Hospital, Unity Health Toronto, Toronto, Ontario, Canada; Department of Surgery, University of Toronto, Toronto, Ontario, Canada; Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.
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8
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Noda T, Blaha A, Fujihara Y, Gert KR, Emori C, Deneke VE, Oura S, Panser K, Lu Y, Berent S, Kodani M, Cabrera-Quio LE, Pauli A, Ikawa M. Sperm membrane proteins DCST1 and DCST2 are required for sperm-egg interaction in mice and fish. Commun Biol 2022; 5:332. [PMID: 35393517 PMCID: PMC8989947 DOI: 10.1038/s42003-022-03289-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Accepted: 03/17/2022] [Indexed: 12/28/2022] Open
Abstract
The process of sperm-egg fusion is critical for successful fertilization, yet the underlying mechanisms that regulate these steps have remained unclear in vertebrates. Here, we show that both mouse and zebrafish DCST1 and DCST2 are necessary in sperm to fertilize the egg, similar to their orthologs SPE-42 and SPE-49 in C. elegans and Sneaky in D. melanogaster. Mouse Dcst1 and Dcst2 single knockout (KO) sperm are able to undergo the acrosome reaction and show normal relocalization of IZUMO1, an essential factor for sperm-egg fusion, to the equatorial segment. While both single KO sperm can bind to the oolemma, they show the fusion defect, resulting that Dcst1 KO males become almost sterile and Dcst2 KO males become sterile. Similar to mice, zebrafish dcst1 KO males are subfertile and dcst2 and dcst1/2 double KO males are sterile. Zebrafish dcst1/2 KO sperm are motile and can approach the egg, but are defective in binding to the oolemma. Furthermore, we find that DCST1 and DCST2 interact with each other and are interdependent. These data demonstrate that DCST1/2 are essential for male fertility in two vertebrate species, highlighting their crucial role as conserved factors in fertilization.
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Affiliation(s)
- Taichi Noda
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Institute of Resource Development and Analysis, Kumamoto University, 2-2-1 Honjo, Chuo-ku, Kumamoto, 860-0811, Japan
- Priority Organization for Innovation and Excellence, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto, 860-8555, Japan
| | - Andreas Blaha
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and the Medical University of Vienna, 1030, Vienna, Austria
| | - Yoshitaka Fujihara
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Department of Bioscience and Genetics, National Cerebral and Cardiovascular Center, 6-1 Kishibe-Shimmachi, Suita, Osaka, 564-8565, Japan
| | - Krista R Gert
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and the Medical University of Vienna, 1030, Vienna, Austria
| | - Chihiro Emori
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Victoria E Deneke
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Seiya Oura
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Karin Panser
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Yonggang Lu
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Sara Berent
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Mayo Kodani
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Luis Enrique Cabrera-Quio
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
- Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and the Medical University of Vienna, 1030, Vienna, Austria
| | - Andrea Pauli
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria.
| | - Masahito Ikawa
- Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
- Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka, 565-0871, Japan.
- The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo, 108-8639, Japan.
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9
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Scortecci JF, Molday LL, Curtis SB, Garces FA, Panwar P, Van Petegem F, Molday RS. Cryo-EM structures of the ABCA4 importer reveal mechanisms underlying substrate binding and Stargardt disease. Nat Commun 2021; 12:5902. [PMID: 34625547 PMCID: PMC8501128 DOI: 10.1038/s41467-021-26161-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 09/20/2021] [Indexed: 12/04/2022] Open
Abstract
ABCA4 is an ATP-binding cassette (ABC) transporter that flips N-retinylidene-phosphatidylethanolamine (N-Ret-PE) from the lumen to the cytoplasmic leaflet of photoreceptor membranes. Loss-of-function mutations cause Stargardt disease (STGD1), a macular dystrophy associated with severe vision loss. To define the mechanisms underlying substrate binding and STGD1, we determine the cryo-EM structure of ABCA4 in its substrate-free and bound states. The two structures are similar and delineate an elongated protein with the two transmembrane domains (TMD) forming an outward facing conformation, extended and twisted exocytoplasmic domains (ECD), and closely opposed nucleotide binding domains. N-Ret-PE is wedged between the two TMDs and a loop from ECD1 within the lumen leaflet consistent with a lateral access mechanism and is stabilized through hydrophobic and ionic interactions with residues from the TMDs and ECDs. Our studies provide a framework for further elucidating the molecular mechanism associated with lipid transport and disease and developing promising disease interventions.
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Affiliation(s)
| | - Laurie L Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Susan B Curtis
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Fabian A Garces
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Pankaj Panwar
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC, Canada.
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, BC, Canada.
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10
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Pao PJ, Hsu MF, Chiang MH, Chen CT, Lee CC, Wang AHJ. Structural basis of an epitope tagging system derived from Haloarcula marismortui bacteriorhodopsin I D94N and its monoclonal antibody GD-26. FEBS J 2021; 289:730-747. [PMID: 34499806 PMCID: PMC9292375 DOI: 10.1111/febs.16184] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 07/12/2021] [Accepted: 09/06/2021] [Indexed: 02/05/2023]
Abstract
Specific antibody interactions with short peptides have made epitope tagging systems a vital tool employed in virtually all fields of biological research. Here, we present a novel epitope tagging system comprised of a monoclonal antibody named GD‐26, which recognises the TD peptide (GTGATPADD) derived from Haloarcula marismortui bacteriorhodopsin I (HmBRI) D94N mutant. The crystal structure of the antigen‐binding fragment (Fab) of GD‐26 complexed with the TD peptide was determined to a resolution of 1.45 Å. The TD peptide was found to adopt a 310 helix conformation within the binding cleft, providing a characteristic peptide structure for recognition by GD‐26 Fab. Based on the structure information, polar and nonpolar forces collectively contribute to the strong binding. Attempts to engineer the TD peptide show that the proline residue is crucial for the formation of the 310 helix in order to fit into the binding cleft. Isothermal calorimetry (ITC) reported a dissociation constant KD of 12 ± 2.8 nm, indicating a strong interaction between the TD peptide and GD‐26 Fab. High specificity of GD‐26 IgG to the TD peptide was demonstrated by western blotting, ELISA and immunofluorescence as only TD‐tagged proteins were detected, suggesting the effectiveness of the GD‐26/TD peptide tagging system. In addition to already‐existing epitope tags such as the FLAG tag and the ALFA tag adopting either extended or α‐helix conformations, the unique 310 helix conformation of the TD peptide together with the corresponding monoclonal antibody GD‐26 offers a novel tagging option for research.
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Affiliation(s)
- Po-Jung Pao
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Min-Feng Hsu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Ming-Hui Chiang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Chun-Ting Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Cheng-Chung Lee
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Andrew H-J Wang
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
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11
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SPATA33 localizes calcineurin to the mitochondria and regulates sperm motility in mice. Proc Natl Acad Sci U S A 2021; 118:2106673118. [PMID: 34446558 PMCID: PMC8536318 DOI: 10.1073/pnas.2106673118] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Calcineurin is a target of immunosuppressive drugs such as cyclosporine A and tacrolimus. In the immune system, calcineurin interacts with NFAT via the PxIxIT motif to activate T cells. In contrast, little is known about the proteins that interact with a testis-enriched calcineurin that is essential for sperm motility and male fertility. Here, we discovered that calcineurin interacts with SPATA33 via a PQIIIT sequence in the testis. Further analyses reveal that SPATA33 plays critical roles in sperm motility and male fertility. Our finding sheds new light on the molecular mechanisms of sperm motility regulation and the etiology of human male fertility. Furthermore, it may help us not only understand reproductive toxicities but also develop nonhormonal male contraceptives. Calcineurin is a calcium-dependent phosphatase that plays roles in a variety of biological processes including immune responses. In spermatozoa, there is a testis-enriched calcineurin composed of PPP3CC and PPP3R2 (sperm calcineurin) that is essential for sperm motility and male fertility. Because sperm calcineurin has been proposed as a target for reversible male contraceptives, identifying proteins that interact with sperm calcineurin widens the choice for developing specific inhibitors. Here, by screening the calcineurin-interacting PxIxIT consensus motif in silico and analyzing the function of candidate proteins through the generation of gene-modified mice, we discovered that SPATA33 interacts with sperm calcineurin via a PQIIIT sequence. Spata33 knockout mice exhibit reduced sperm motility because of an inflexible midpiece, leading to impaired male fertility, which phenocopies Ppp3cc and Ppp3r2 knockout mice. Further analysis reveals that sperm calcineurin disappears from the mitochondria in the Spata33 knockout testis. In addition, immunoprecipitation analysis indicates that sperm calcineurin interacts with not only SPATA33 but also the mitochondrial protein VDAC2. These results indicate that SPATA33 localizes calcineurin to the mitochondria and regulates sperm motility.
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12
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Pamula F, Tsai CJ. Biochemical Characterization of GPCR-G Protein Complex Formation. Methods Mol Biol 2021; 2302:37-48. [PMID: 33877621 DOI: 10.1007/978-1-0716-1394-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The complex of G protein-coupled receptors (GPCR) and G proteins is the core assembly in GPCR signaling in eukaryotes. With the recent development of cryo-electron microscopy, there has been a rapid growth in structures of GPCR-G protein complexes solved to near-atomic resolution, giving important insights into this signaling complex. Here we describe the biochemical protocol to study the interaction between GPCRs and G proteins before preparation of GPCR-G protein complexes for structural studies. We use gel filtration to analyze the binding properties between GPCR and G protein with the presence of agonist or antagonist, as well as the complex dissociation in the presence of GTP analogue. Methods used in the protocol are affinity purification and gel filtration, which are also commonly used in protein sample preparation for structural work. Therefore, the protocol can be easily adapted for large-scale sample preparation.
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Affiliation(s)
- Filip Pamula
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland
| | - Ching-Ju Tsai
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland.
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13
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Sander CL, Sears AE, Pinto AF, Choi EH, Kahremany S, Gao F, Salom D, Jin H, Pardon E, Suh S, Dong Z, Steyaert J, Saghatelian A, Skowronska-Krawczyk D, Kiser PD, Palczewski K. Nano-scale resolution of native retinal rod disk membranes reveals differences in lipid composition. J Cell Biol 2021; 220:e202101063. [PMID: 34132745 PMCID: PMC8240855 DOI: 10.1083/jcb.202101063] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 04/26/2021] [Accepted: 05/18/2021] [Indexed: 02/07/2023] Open
Abstract
Photoreceptors rely on distinct membrane compartments to support their specialized function. Unlike protein localization, identification of critical differences in membrane content has not yet been expanded to lipids, due to the difficulty of isolating domain-specific samples. We have overcome this by using SMA to coimmunopurify membrane proteins and their native lipids from two regions of photoreceptor ROS disks. Each sample's copurified lipids were subjected to untargeted lipidomic and fatty acid analysis. Extensive differences between center (rhodopsin) and rim (ABCA4 and PRPH2/ROM1) samples included a lower PC to PE ratio and increased LC- and VLC-PUFAs in the center relative to the rim region, which was enriched in shorter, saturated FAs. The comparatively few differences between the two rim samples likely reflect specific protein-lipid interactions. High-resolution profiling of the ROS disk lipid composition gives new insights into how intricate membrane structure and protein activity are balanced within the ROS, and provides a model for future studies of other complex cellular structures.
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Affiliation(s)
- Christopher L. Sander
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Avery E. Sears
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Antonio F.M. Pinto
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA
| | - Elliot H. Choi
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Shirin Kahremany
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Fangyuan Gao
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - David Salom
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Hui Jin
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
| | - Els Pardon
- Vlaams Instituut voor Biotechnologie–Vrije Universiteit Brussel Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Susie Suh
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Zhiqian Dong
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
| | - Jan Steyaert
- Vlaams Instituut voor Biotechnologie–Vrije Universiteit Brussel Center for Structural Biology, Vlaams Instituut voor Biotechnologie, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Alan Saghatelian
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA
| | - Dorota Skowronska-Krawczyk
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA
| | - Philip D. Kiser
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA
- Research Service, VA Long Beach Healthcare System, Long Beach, CA
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, Irvine, CA
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA
- Department of Chemistry, University of California, Irvine, Irvine, CA
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14
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Robinson RA, Griffiths SC, van de Haar LL, Malinauskas T, van Battum EY, Zelina P, Schwab RA, Karia D, Malinauskaite L, Brignani S, van den Munkhof MH, Düdükcü Ö, De Ruiter AA, Van den Heuvel DMA, Bishop B, Elegheert J, Aricescu AR, Pasterkamp RJ, Siebold C. Simultaneous binding of Guidance Cues NET1 and RGM blocks extracellular NEO1 signaling. Cell 2021; 184:2103-2120.e31. [PMID: 33740419 PMCID: PMC8063088 DOI: 10.1016/j.cell.2021.02.045] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 01/15/2021] [Accepted: 02/22/2021] [Indexed: 12/13/2022]
Abstract
During cell migration or differentiation, cell surface receptors are simultaneously exposed to different ligands. However, it is often unclear how these extracellular signals are integrated. Neogenin (NEO1) acts as an attractive guidance receptor when the Netrin-1 (NET1) ligand binds, but it mediates repulsion via repulsive guidance molecule (RGM) ligands. Here, we show that signal integration occurs through the formation of a ternary NEO1-NET1-RGM complex, which triggers reciprocal silencing of downstream signaling. Our NEO1-NET1-RGM structures reveal a "trimer-of-trimers" super-assembly, which exists in the cell membrane. Super-assembly formation results in inhibition of RGMA-NEO1-mediated growth cone collapse and RGMA- or NET1-NEO1-mediated neuron migration, by preventing formation of signaling-compatible RGM-NEO1 complexes and NET1-induced NEO1 ectodomain clustering. These results illustrate how simultaneous binding of ligands with opposing functions, to a single receptor, does not lead to competition for binding, but to formation of a super-complex that diminishes their functional outputs.
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Affiliation(s)
- Ross A Robinson
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Samuel C Griffiths
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Lieke L van de Haar
- Department of Translational Neuroscience, UMC Utrecht Brain Center, University Medical Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Tomas Malinauskas
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Eljo Y van Battum
- Department of Translational Neuroscience, UMC Utrecht Brain Center, University Medical Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Pavol Zelina
- Department of Translational Neuroscience, UMC Utrecht Brain Center, University Medical Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Rebekka A Schwab
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Dimple Karia
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Lina Malinauskaite
- MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Sara Brignani
- Department of Translational Neuroscience, UMC Utrecht Brain Center, University Medical Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Marleen H van den Munkhof
- Department of Translational Neuroscience, UMC Utrecht Brain Center, University Medical Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Özge Düdükcü
- Department of Translational Neuroscience, UMC Utrecht Brain Center, University Medical Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Anna A De Ruiter
- Department of Translational Neuroscience, UMC Utrecht Brain Center, University Medical Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Dianne M A Van den Heuvel
- Department of Translational Neuroscience, UMC Utrecht Brain Center, University Medical Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands
| | - Benjamin Bishop
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Jonathan Elegheert
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - A Radu Aricescu
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK; MRC Laboratory of Molecular Biology, Cambridge Biomedical Campus, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - R Jeroen Pasterkamp
- Department of Translational Neuroscience, UMC Utrecht Brain Center, University Medical Center, Utrecht University, Universiteitsweg 100, 3584 CG Utrecht, the Netherlands.
| | - Christian Siebold
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK.
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15
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Fluck EC, Pumroy RA, Moiseenkova-Bell VY. Production and purification of TRPV2 and TRPV5 for structural and functional studies. Methods Enzymol 2021; 653:49-74. [PMID: 34099181 DOI: 10.1016/bs.mie.2021.02.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The transient receptor potential (TRP) vanilloid 2 (TRPV2) and TRP vanilloid 5 (TRPV5) cation channels play an important role in various physiological and pathophysiological processes. The heterologous expression and purification of these channels is critical for functional and structural characterization of these important proteins. Full-length rat TRPV2 and rabbit TRPV5 can both be expressed in Saccharomyces cerevisiae and affinity purified using the 1D4 epitope and antibody to yield pure, functional channels. Further, these channels can be reconstituted into lipid nanodiscs for a more functionally relevant environment. Presented here are protocols for the expression of full-length rat TRPV2 and rabbit TRPV5 in Saccharomyces cerevisiae, their affinity purification, and their reconstitution into nanodiscs for structural and functional studies.
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Affiliation(s)
- Edwin C Fluck
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA, United States; Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Ruth A Pumroy
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA, United States
| | - Vera Y Moiseenkova-Bell
- Department of Systems Pharmacology and Translational Therapeutics, University of Pennsylvania, Philadelphia, PA, United States.
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16
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Koretz KS, McGraw CE, Stradley S, Elbaradei A, Malmstadt N, Robinson AS. Characterization of binding kinetics of A 2AR to Gα s protein by surface plasmon resonance. Biophys J 2021; 120:1641-1649. [PMID: 33675761 DOI: 10.1016/j.bpj.2021.02.032] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 02/11/2021] [Accepted: 02/17/2021] [Indexed: 01/09/2023] Open
Abstract
Because of their surface localization, G protein-coupled receptors (GPCRs) are often pharmaceutical targets as they respond to a variety of extracellular stimuli (e.g., light, hormones, small molecules) that may activate or inhibit a downstream signaling response. The adenosine A2A receptor (A2AR) is a well-characterized GPCR that is expressed widely throughout the human body, with over 10 crystal structures determined. Truncation of the A2AR C-terminus is necessary for crystallization as this portion of the receptor is long and unstructured; however, previous work suggests shortening of the A2AR C-terminus from 412 to 316 amino acids (A2AΔ316R) ablates downstream signaling, as measured by cAMP production, to below that of constitutive full-length A2AR levels. As cAMP production is downstream of the first activation event-coupling of G protein to its receptor-investigating that first step in activation is important in understanding how the truncation effects native GPCR function. Here, using purified receptor and Gαs proteins, we characterize the association of A2AR and A2AΔ316R to Gαs with and without GDP or GTPγs using surface plasmon resonance (SPR). Gαs affinity for A2AR was greatest for apo-Gαs, moderately affected in the presence of GDP and nearly completely ablated by the addition of GTPγs. Truncation of the A2AR C-terminus (A2AΔ316R) decreased the affinity of the unliganded receptor for Gαs by ∼20%, suggesting small changes to binding can greatly impact downstream signaling.
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Affiliation(s)
- Kirsten S Koretz
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana; Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Claire E McGraw
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana
| | - Steven Stradley
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana
| | - Ahmed Elbaradei
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California
| | - Noah Malmstadt
- Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, California
| | - Anne S Robinson
- Department of Chemical and Biomolecular Engineering, Tulane University, New Orleans, Louisiana; Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania.
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17
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Gao Y, Eskici G, Ramachandran S, Poitevin F, Seven AB, Panova O, Skiniotis G, Cerione RA. Structure of the Visual Signaling Complex between Transducin and Phosphodiesterase 6. Mol Cell 2020; 80:237-245.e4. [PMID: 33007200 DOI: 10.1016/j.molcel.2020.09.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/04/2020] [Accepted: 09/09/2020] [Indexed: 12/21/2022]
Abstract
Heterotrimeric G proteins communicate signals from activated G protein-coupled receptors to downstream effector proteins. In the phototransduction pathway responsible for vertebrate vision, the G protein-effector complex is composed of the GTP-bound transducin α subunit (GαT·GTP) and the cyclic GMP (cGMP) phosphodiesterase 6 (PDE6), which stimulates cGMP hydrolysis, leading to hyperpolarization of the photoreceptor cell. Here we report a cryo-electron microscopy (cryoEM) structure of PDE6 complexed to GTP-bound GαT. The structure reveals two GαT·GTP subunits engaging the PDE6 hetero-tetramer at both the PDE6 catalytic core and the PDEγ subunits, driving extensive rearrangements to relieve all inhibitory constraints on enzyme catalysis. Analysis of the conformational ensemble in the cryoEM data highlights the dynamic nature of the contacts between the two GαT·GTP subunits and PDE6 that supports an alternating-site catalytic mechanism.
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Affiliation(s)
- Yang Gao
- 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
| | - Gözde Eskici
- 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
| | - Sekar Ramachandran
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA; Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Frédéric Poitevin
- 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
| | - Alpay Burak Seven
- 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
| | - Ouliana Panova
- 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
| | - Georgios Skiniotis
- 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.
| | - Richard A Cerione
- Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA; Department of Molecular Medicine, Cornell University, Ithaca, NY 14853, USA.
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18
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Perdomo D, Bubis J. Light or tyrosine phosphorylation recruits retinal rod outer segment proteins to lipid rafts. Biochimie 2020; 177:1-12. [PMID: 32758687 DOI: 10.1016/j.biochi.2020.07.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Revised: 07/22/2020] [Accepted: 07/26/2020] [Indexed: 02/06/2023]
Abstract
Lipid rafts are localized liquid-ordered regions of the plasma membrane that contain high levels of cholesterol and glycosphingolipids, and are resistant to extraction with nonionic detergents. Retinal photoreceptor cells contain detergent-resistant membrane microdomains (DRM), which were isolated here from bovine rod outer segments (ROS) under dark and light conditions. Rhodopsin (R) was present in both DRM and detergent soluble fractions (DSF), and detergent-insoluble ROS rafts were enriched in caveolin 1 (Cav-1) and c-Src. In the dark, arrestin and its 44-kDa truncated form (p44) were present mainly in DSF; however, p44 was translocated to DRM under illumination. Similarly, transducin (T) was mainly present in DSF in the dark, but it was recruited toward the DRM fraction following photolysis. DRM were also prepared in the absence or presence of Mg-ATP, guanosine 5'-3-O-(thio)triphosphate (GTPγS), or both. Although GTPγS released T into DSF in the light, GTPγS-activated T was retained in DRM when Mg2+ and ATP were added. Moreover, T was always tyrosine-phosphorylated under light conditions, which suggested that T phosphorylation prevents its GTPγS-induced release from DRM. In addition, treatment with the tyrosine kinase inhibitor genistein prevented the segregation of T to the rafts. In contrast, no localization difference was seen in the presence of Mg-ATP for Cav-1, c-Src, R and both forms of arrestin. Interestingly, immunoprecipitation assays followed by Western blot analyses under light conditions showed the formation of multimeric complexes containing R, T, c-Src, p44 and Cav-1 in DRM, where T and c-Src were tyrosine-phosphorylated.
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Affiliation(s)
- Deisy Perdomo
- Departamento de Biología Celular, Universidad Simón Bolívar, Valle de Sartenejas, Baruta, Caracas, Venezuela.
| | - José Bubis
- Departamento de Biología Celular, Universidad Simón Bolívar, Valle de Sartenejas, Baruta, Caracas, Venezuela.
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19
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Jain AR, Britton ZT, Markwalter CE, Robinson AS. Improved ligand-binding- and signaling-competent human NK2R yields in yeast using a chimera with the rat NK2R C-terminus enable NK2R-G protein signaling platform. Protein Eng Des Sel 2020; 32:459-469. [PMID: 32400863 DOI: 10.1093/protein/gzaa009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 03/09/2020] [Accepted: 04/16/2020] [Indexed: 02/07/2023] Open
Abstract
The tachykinin 2 receptor (NK2R) plays critical roles in gastrointestinal, respiratory and mental disorders and is a well-recognized target for therapeutic intervention. To date, therapeutics targeting NK2R have failed to meet regulatory agency approval due in large part to the limited characterization of the receptor-ligand interaction and downstream signaling. Herein, we report a protein engineering strategy to improve ligand-binding- and signaling-competent human NK2R that enables a yeast-based NK2R signaling platform by creating chimeras utilizing sequences from rat NK2R. We demonstrate that NK2R chimeras incorporating the rat NK2R C-terminus exhibited improved ligand-binding yields and downstream signaling in engineered yeast strains and mammalian cells, where observed yields were better than 4-fold over wild type. This work builds on our previous studies that suggest exchanging the C-termini of related and well-expressed family members may be a general protein engineering strategy to overcome limitations to ligand-binding and signaling-competent G protein-coupled receptor yields in yeast. We expect these efforts to result in NK2R drug candidates with better characterized signaling properties.
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Affiliation(s)
- Abhinav R Jain
- Department of Chemical and Biomolecular Engineering, Tulane University, 6823 St Charles Ave, New Orleans, LA, 70118, USA
| | - Zachary T Britton
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St, Newark, DE, 19716, USA.,AstraZeneca, Antibody Discovery and Protein Engineering, Gaithersburg, MD 20878, USA
| | - Chester E Markwalter
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St, Newark, DE, 19716, USA.,Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Anne S Robinson
- Department of Chemical and Biomolecular Engineering, Tulane University, 6823 St Charles Ave, New Orleans, LA, 70118, USA.,Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy St, Newark, DE, 19716, USA.,Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
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20
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Sperm proteins SOF1, TMEM95, and SPACA6 are required for sperm-oocyte fusion in mice. Proc Natl Acad Sci U S A 2020; 117:11493-11502. [PMID: 32393636 PMCID: PMC7261011 DOI: 10.1073/pnas.1922650117] [Citation(s) in RCA: 82] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sperm-oocyte membrane fusion is one of the most important events for fertilization. So far, IZUMO1 and Fertilization Influencing Membrane Protein (FIMP) on the sperm membrane and CD9 and JUNO (IZUMO1R/FOLR4) on the oocyte membrane have been identified as fusion-required proteins. However, the molecular mechanisms for sperm-oocyte fusion are still unclear. Here, we show that testis-enriched genes, sperm-oocyte fusion required 1 (Sof1/Llcfc1/1700034O15Rik), transmembrane protein 95 (Tmem95), and sperm acrosome associated 6 (Spaca6), encode sperm proteins required for sperm-oocyte fusion in mice. These knockout (KO) spermatozoa carry IZUMO1 but cannot fuse with the oocyte plasma membrane, leading to male sterility. Transgenic mice which expressed mouse Sof1, Tmem95, and Spaca6 rescued the sterility of Sof1, Tmem95, and Spaca6 KO males, respectively. SOF1 and SPACA6 remain in acrosome-reacted spermatozoa, and SPACA6 translocates to the equatorial segment of these spermatozoa. The coexpression of SOF1, TMEM95, and SPACA6 in IZUMO1-expressing cultured cells did not enhance their ability to adhere to the oocyte membrane or allow them to fuse with oocytes. SOF1, TMEM95, and SPACA6 may function cooperatively with IZUMO1 and/or unknown fusogens in sperm-oocyte fusion.
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21
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Pamula F, Mühle J, Blanc A, Nehmé R, Edwards PC, Tate CG, Tsai CJ. Strategic Screening and Characterization of the Visual GPCR-mini-G Protein Signaling Complex for Successful Crystallization. J Vis Exp 2020. [PMID: 32225143 PMCID: PMC7250641 DOI: 10.3791/60747] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The key to determining crystal structures of membrane protein complexes is the quality of the sample prior to crystallization. In particular, the choice of detergent is critical, because it affects both the stability and monodispersity of the complex. We recently determined the crystal structure of an active state of bovine rhodopsin coupled to an engineered G protein, mini-Go, at 3.1 Å resolution. Here, we detail the procedure for optimizing the preparation of the rhodopsin–mini-Go complex. Dark-state rhodopsin was prepared in classical and neopentyl glycol (NPG) detergents, followed by complex formation with mini-Go under light exposure. The stability of the rhodopsin was assessed by ultraviolet-visible (UV-VIS) spectroscopy, which monitors the reconstitution into rhodopsin of the light-sensitive ligand, 9-cis retinal. Automated size-exclusion chromatography (SEC) was used to characterize the monodispersity of rhodopsin and the rhodopsin–mini-Go complex. SDS-polyacrylamide electrophoresis (SDS-PAGE) confirmed the formation of the complex by identifying a 1:1 molar ratio between rhodopsin and mini-Go after staining the gel with Coomassie blue. After cross-validating all this analytical data, we eliminated unsuitable detergents and continued with the best candidate detergent for large-scale preparation and crystallization. An additional problem arose from the heterogeneity of N-glycosylation. Heterologously-expressed rhodopsin was observed on SDS-PAGE to have two different N-glycosylated populations, which would probably have hindered crystallogenesis. Therefore, different deglycosylation enzymes were tested, and endoglycosidase F1 (EndoF1) produced rhodopsin with a single species of N-glycosylation. With this strategic pipeline for characterizing protein quality, preparation of the rhodopsin–mini-Go complex was optimized to deliver the crystal structure. This was only the third crystal structure of a GPCR–G protein signaling complex. This approach can also be generalized for other membrane proteins and their complexes to facilitate sample preparation and structure determination.
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Affiliation(s)
- Filip Pamula
- Laboratory of Biomolecular Research, Paul Scherrer Institute; Department of Biology, ETH Zürich;
| | - Jonas Mühle
- Laboratory of Biomolecular Research, Paul Scherrer Institute
| | - Alain Blanc
- Center for Radiopharmaceutical Sciences, Paul Scherrer Institute
| | - Rony Nehmé
- Laboratory of Molecular Biology, Medical Research Council
| | | | | | - Ching-Ju Tsai
- Laboratory of Biomolecular Research, Paul Scherrer Institute;
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22
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Ni T, Jiao F, Yu X, Aden S, Ginger L, Williams SI, Bai F, Pražák V, Karia D, Stansfeld P, Zhang P, Munson G, Anderluh G, Scheuring S, Gilbert RJC. Structure and mechanism of bactericidal mammalian perforin-2, an ancient agent of innate immunity. SCIENCE ADVANCES 2020; 6:eaax8286. [PMID: 32064340 PMCID: PMC6989145 DOI: 10.1126/sciadv.aax8286] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 11/21/2019] [Indexed: 05/21/2023]
Abstract
Perforin-2 (MPEG1) is thought to enable the killing of invading microbes engulfed by macrophages and other phagocytes, forming pores in their membranes. Loss of perforin-2 renders individual phagocytes and whole organisms significantly more susceptible to bacterial pathogens. Here, we reveal the mechanism of perforin-2 activation and activity using atomic structures of pre-pore and pore assemblies, high-speed atomic force microscopy, and functional assays. Perforin-2 forms a pre-pore assembly in which its pore-forming domain points in the opposite direction to its membrane-targeting domain. Acidification then triggers pore formation, via a 180° conformational change. This novel and unexpected mechanism prevents premature bactericidal attack and may have played a key role in the evolution of all perforin family proteins.
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Affiliation(s)
- Tao Ni
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Fang Jiao
- Department of Anesthesiology, Weill Cornell Medical College, 1300 York Ave., New York, NY 10065, USA
| | - Xiulian Yu
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
- Calleva Research Centre for Evolution and Human Sciences, Magdalen College, University of Oxford, Oxford OX1 4AU, UK
| | - Saša Aden
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Lucy Ginger
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Sophie I. Williams
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Fangfang Bai
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Vojtěch Pražák
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Dimple Karia
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Phillip Stansfeld
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Peijun Zhang
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - George Munson
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Gregor Anderluh
- Department of Molecular Biology and Nanobiotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
| | - Simon Scheuring
- Department of Anesthesiology, Weill Cornell Medical College, 1300 York Ave., New York, NY 10065, USA
- Department of Physiology and Biophysics, Weill Cornell Medical College, 1300 York Ave., New York, NY 10065, USA
- Corresponding author. (S.S.); (R.J.C.G.)
| | - Robert J. C. Gilbert
- Division of Structural Biology, Wellcome Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
- Calleva Research Centre for Evolution and Human Sciences, Magdalen College, University of Oxford, Oxford OX1 4AU, UK
- Corresponding author. (S.S.); (R.J.C.G.)
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23
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Zhang J, Choi EH, Tworak A, Salom D, Leinonen H, Sander CL, Hoang TV, Handa JT, Blackshaw S, Palczewska G, Kiser PD, Palczewski K. Photic generation of 11- cis-retinal in bovine retinal pigment epithelium. J Biol Chem 2019; 294:19137-19154. [PMID: 31694912 DOI: 10.1074/jbc.ra119.011169] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 10/25/2019] [Indexed: 12/19/2022] Open
Abstract
Photoisomerization of the 11-cis-retinal chromophore of rod and cone visual pigments to an all-trans-configuration is the initiating event for vision in vertebrates. The regeneration of 11-cis-retinal, necessary for sustained visual function, is an endergonic process normally conducted by specialized enzyme systems. However, 11-cis-retinal also can be formed through reverse photoisomerization from all-trans-retinal. A nonvisual opsin known as retinal pigment epithelium (RPE)-retinal G-protein-coupled receptor (RGR) was previously shown to mediate visual chromophore regeneration in photic conditions, but conflicting results have cast doubt on its role as a photoisomerase. Here, we describe high-level production of 11-cis-retinal from RPE membranes stimulated by illumination at a narrow band of wavelengths. This activity was associated with RGR and enhanced by cellular retinaldehyde-binding protein (CRALBP), which binds the 11-cis-retinal produced by RGR and prevents its re-isomerization to all-trans-retinal. The activity was recapitulated with cells heterologously expressing RGR and with purified recombinant RGR. Using an RGR variant, K255A, we confirmed that a Schiff base linkage at Lys-255 is critical for substrate binding and isomerization. Single-cell RNA-Seq analysis of the retina and RPE tissue confirmed that RGR is expressed in human and bovine RPE and Müller glia, whereas mouse RGR is expressed in RPE but not in Müller glia. These results provide key insights into the mechanisms of physiological retinoid photoisomerization and suggest a novel mechanism by which RGR, in concert with CRALBP, regenerates the visual chromophore in the RPE under sustained light conditions.
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Affiliation(s)
- Jianye Zhang
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697
| | - Elliot H Choi
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697.,Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Aleksander Tworak
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697
| | - David Salom
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697
| | - Henri Leinonen
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697
| | - Christopher L Sander
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697.,Department of Pharmacology, Case Western Reserve University, Cleveland, Ohio 44106
| | - Thanh V Hoang
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - James T Handa
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.,Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287
| | | | - Philip D Kiser
- Department of Physiology and Biophysics, University of California, Irvine, California 92697.,Research Service, Veterans Affairs Long Beach Healthcare System, Long Beach, California 90822
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California 92697
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24
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Britton ZT, London TB, Carrell J, Dosanjh B, Wilkinson T, Bowen MA, Wu H, Dall’Acqua WF, Marelli M, Mazor Y. Tag-on-Demand: exploiting amber codon suppression technology for the enrichment of high-expressing membrane protein cell lines. Protein Eng Des Sel 2019; 31:389-398. [DOI: 10.1093/protein/gzy032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 11/16/2018] [Accepted: 12/18/2018] [Indexed: 12/20/2022] Open
Affiliation(s)
- Zachary T Britton
- Antibody Discovery and Protein Engineering, MedImmune, Gaithersburg, MD, USA
| | - Timothy B London
- Antibody Discovery and Protein Engineering, MedImmune, Cambridge, UK
- Current affiliation: TC BioPharm Limited, Glasgow, UK
| | - Jeffrey Carrell
- Respiratory, Inflammation and Autoimmune, MedImmune, Gaithersburg, MD, USA
| | - Bhupinder Dosanjh
- Antibody Discovery and Protein Engineering, MedImmune, Cambridge, UK
| | - Trevor Wilkinson
- Antibody Discovery and Protein Engineering, MedImmune, Cambridge, UK
| | - Michael A Bowen
- Antibody Discovery and Protein Engineering, MedImmune, Gaithersburg, MD, USA
| | - Herren Wu
- Antibody Discovery and Protein Engineering, MedImmune, Gaithersburg, MD, USA
| | | | - Marcello Marelli
- Antibody Discovery and Protein Engineering, MedImmune, Gaithersburg, MD, USA
| | - Yariv Mazor
- Antibody Discovery and Protein Engineering, MedImmune, Gaithersburg, MD, USA
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25
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Upton EC, Maciunas LJ, Loll PJ. Vancomycin does not affect the enzymatic activities of purified VanSA. PLoS One 2019; 14:e0210627. [PMID: 30677074 PMCID: PMC6345502 DOI: 10.1371/journal.pone.0210627] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 12/29/2018] [Indexed: 11/18/2022] Open
Abstract
VanS is a membrane-bound sensor histidine kinase responsible for sensing vancomycin and activating transcription of vancomycin-resistance genes. In the presence of vancomycin, VanS phosphorylates the transcription factor VanR, converting it to its transcriptionally active form. In the absence of vancomycin, VanS dephosphorylates VanR, thereby maintaining it in a transcriptionally inactive state. To date, the mechanistic details of how vancomycin modulates VanS activity have remained elusive. We have therefore studied these details in an in vitro system, using the full-length VanS and VanR proteins responsible for type-A vancomycin resistance in enterococci. Both detergent- and amphipol-solubilized VanSA display all the enzymatic activities expected for a sensor histidine kinase, with amphipol reconstitution providing a marked boost in overall activity relative to detergent solubilization. A putative constitutively activated VanSA mutant (T168K) was constructed and purified, and was found to exhibit the expected reduction in phosphatase activity, providing confidence that detergent-solubilized VanSA behaves in a physiologically relevant manner. In both detergent and amphipol solutions, VanSA’s enzymatic activities were found to be insensitive to vancomycin, even at levels many times higher than the antibiotic’s minimum inhibitory concentration. This result argues against direct activation of VanSA via formation of a binary antibiotic-kinase complex, suggesting instead that either additional factors are required to form a functional signaling complex, or that activation does not require direct interaction with the antibiotic.
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Affiliation(s)
- Elizabeth C. Upton
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Lina J. Maciunas
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Patrick J. Loll
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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26
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Baronas VA, Yang RY, Morales LC, Sipione S, Kurata HT. Slc7a5 regulates Kv1.2 channels and modifies functional outcomes of epilepsy-linked channel mutations. Nat Commun 2018; 9:4417. [PMID: 30356053 PMCID: PMC6200743 DOI: 10.1038/s41467-018-06859-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 10/02/2018] [Indexed: 01/25/2023] Open
Abstract
Kv1.2 is a prominent voltage-gated potassium channel that influences action potential generation and propagation in the central nervous system. We explored multi-protein complexes containing Kv1.2 using mass spectrometry followed by screening for effects on Kv1.2. We report that Slc7a5, a neutral amino acid transporter, has a profound impact on Kv1.2. Co-expression with Slc7a5 reduces total Kv1.2 protein, and dramatically hyperpolarizes the voltage-dependence of activation by -47 mV. These effects are attenuated by expression of Slc3a2, a known binding partner of Slc7a5. The profound Slc7a5-mediated current suppression is partly explained by a combination of gating effects including accelerated inactivation and a hyperpolarizing shift of channel activation, causing channels to accumulate in a non-conducting state. Two recently reported Slc7a5 mutations linked to neurodevelopmental delay exhibit a localization defect and have attenuated effects on Kv1.2. In addition, epilepsy-linked gain-of-function Kv1.2 mutants exhibit enhanced sensitivity to Slc7a5.
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Affiliation(s)
- Victoria A Baronas
- Department of Pharmacology, University of Alberta, Edmonton, T6G 2R3, Canada
| | - Runying Y Yang
- Department of Pharmacology, University of Alberta, Edmonton, T6G 2R3, Canada
| | - Luis Carlos Morales
- Department of Pharmacology, University of Alberta, Edmonton, T6G 2R3, Canada
| | - Simonetta Sipione
- Department of Pharmacology, University of Alberta, Edmonton, T6G 2R3, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada
| | - Harley T Kurata
- Department of Pharmacology, University of Alberta, Edmonton, T6G 2R3, Canada. .,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, Canada. .,Alberta Diabetes Institute, University of Alberta, Edmonton, Canada.
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27
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Wang J, Molday LL, Hii T, Coleman JA, Wen T, Andersen JP, Molday RS. Proteomic Analysis and Functional Characterization of P4-ATPase Phospholipid Flippases from Murine Tissues. Sci Rep 2018; 8:10795. [PMID: 30018401 PMCID: PMC6050252 DOI: 10.1038/s41598-018-29108-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 07/05/2018] [Indexed: 01/31/2023] Open
Abstract
P4-ATPases are a subfamily of P-type ATPases that flip phospholipids across membranes to generate lipid asymmetry, a property vital to many cellular processes. Mutations in several P4-ATPases have been linked to severe neurodegenerative and metabolic disorders. Most P4-ATPases associate with one of three accessory subunit isoforms known as CDC50A (TMEM30A), CDC50B (TMEM30B), and CDC50C (TMEM30C). To identify P4-ATPases that associate with CDC50A, in vivo, and determine their tissue distribution, we isolated P4-ATPases-CDC50A complexes from retina, brain, liver, testes, and kidney on a CDC50A immunoaffinity column and identified and quantified P4-ATPases from their tryptic peptides by mass spectrometry. Of the 12 P4-ATPase that associate with CDC50 subunits, 10 P4-ATPases were detected. Four P4-ATPases (ATP8A1, ATP11A, ATP11B, ATP11C) were present in all five tissues. ATP10D was found in low amounts in liver, brain, testes, and kidney, and ATP8A2 was present in significant amounts in retina, brain, and testes. ATP8B1 was detected only in liver, ATP8B3 and ATP10A only in testes, and ATP8B2 primarily in brain. We also show that ATP11A, ATP11B and ATP11C, like ATP8A1 and ATP8A2, selectively flip phosphatidylserine and phosphatidylethanolamine across membranes. These studies provide new insight into the tissue distribution, relative abundance, subunit interactions and substrate specificity of P4-ATPase-CDC50A complexes.
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Affiliation(s)
- Jiao Wang
- Department of Biochemistry and Molecular Biology, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
- Laboratory of Molecular Neural Biology, Institute of Systems Biology, School of Life Sciences, Shanghai University, Shanghai, 200444, China
| | - Laurie L Molday
- Department of Biochemistry and Molecular Biology, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Theresa Hii
- Department of Biochemistry and Molecular Biology, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Jonathan A Coleman
- Department of Biochemistry and Molecular Biology, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada
| | - Tieqiao Wen
- Laboratory of Molecular Neural Biology, Institute of Systems Biology, School of Life Sciences, Shanghai University, Shanghai, 200444, China
| | - Jens P Andersen
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, Bldg. 1160, DK-8000, Aarhus C, Denmark
| | - Robert S Molday
- Department of Biochemistry and Molecular Biology, Centre for Macular Research, University of British Columbia, Vancouver, British Columbia, V6T 1Z3, Canada.
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28
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Lebensohn AM, Rohatgi R. R-spondins can potentiate WNT signaling without LGRs. eLife 2018; 7:33126. [PMID: 29405118 PMCID: PMC5800842 DOI: 10.7554/elife.33126] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2017] [Accepted: 12/22/2017] [Indexed: 12/21/2022] Open
Abstract
The WNT signaling pathway regulates patterning and morphogenesis during development and promotes tissue renewal and regeneration in adults. The R-spondin (RSPO) family of four secreted proteins, RSPO1-4, amplifies target cell sensitivity to WNT ligands by increasing WNT receptor levels. Leucine-rich repeat-containing G-protein coupled receptors (LGRs) 4-6 are considered obligate high-affinity receptors for RSPOs. We discovered that RSPO2 and RSPO3, but not RSPO1 or RSPO4, can potentiate WNT/β-catenin signaling in the absence of all three LGRs. By mapping the domains on RSPO3 that are necessary and sufficient for this activity, we show that the requirement for LGRs is dictated by the interaction between RSPOs and the ZNRF3/RNF43 E3 ubiquitin ligases and that LGR-independent signaling depends on heparan sulfate proteoglycans (HSPGs). We propose that RSPOs can potentiate WNT signals through distinct mechanisms that differ in their use of either LGRs or HSPGs, with implications for understanding their biological functions.
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Affiliation(s)
- Andres M Lebensohn
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States.,Department of Medicine, Stanford University School of Medicine, Stanford, United States
| | - Rajat Rohatgi
- Department of Biochemistry, Stanford University School of Medicine, Stanford, United States.,Department of Medicine, Stanford University School of Medicine, Stanford, United States
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29
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Darling TL, Sherwood LJ, Hayhurst A. Intracellular Crosslinking of Filoviral Nucleoproteins with Xintrabodies Restricts Viral Packaging. Front Immunol 2017; 8:1197. [PMID: 29021793 PMCID: PMC5623874 DOI: 10.3389/fimmu.2017.01197] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Accepted: 09/11/2017] [Indexed: 12/24/2022] Open
Abstract
Viruses assemble large macromolecular repeat structures that become part of the infectious particles or virions. Ribonucleocapsids (RNCs) of negative strand RNA viruses are a prime example where repetition of nucleoprotein (NP) along the genome creates a core polymeric helical scaffold that accommodates other nucleocapsid proteins including viral polymerase. The RNCs are transported through the cytosol for packaging into virions through association with viral matrix proteins at cell membranes. We hypothesized that RNC would be ideal targets for crosslinkers engineered to promote aberrant protein–protein interactions, thereby blocking their orderly transport and packaging. Previously, we had generated single-domain antibodies (sdAbs) against Filoviruses that have all targeted highly conserved C-terminal regions of NP known to be repetitively exposed along the length of the RNCs of Marburgvirus (MARV) and Ebolavirus (EBOV). Our crosslinker design consisted of dimeric sdAb expressed intracellularly, which we call Xintrabodies (X- for crosslinking). Electron microscopy of purified NP polymers incubated with purified sdAb constructs showed NP aggregation occurred in a genus-specific manner with dimeric and not monomeric sdAb. A virus-like particle (VLP) assay was used for initial evaluation where we found that dimeric sdAb inhibited NP incorporation into VP40-based VLPs whereas monomeric sdAb did not. Inhibition of NP packaging was genus specific. Confocal microscopy revealed dimeric sdAb was diffuse when expressed alone but focused on pools of NP when the two were coexpressed, while monomeric sdAb showed ambivalent partition. Infection of stable Vero cell lines expressing dimeric sdAb specific for either MARV or EBOV NP resulted in smaller plaques and reduced progeny of cognate virus relative to wild-type Vero cells. Though the impact was marginal at later time-points, the collective data suggest that viral replication can be reduced by crosslinking intracellular NP using relatively small amounts of dimeric sdAb to restrict NP packaging. The stoichiometry and ease of application of the approach would likely benefit from transitioning away from intracellular expression of crosslinking sdAb to exogenous delivery of antibody. By retuning sdAb specificity, the approach of crosslinking highly conserved regions of assembly critical proteins may well be applicable to inhibiting replication processes of a broad spectrum of viruses.
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Affiliation(s)
- Tamarand Lee Darling
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, United States.,Department of Microbiology, Immunology and Molecular Genetics, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Laura Jo Sherwood
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, United States
| | - Andrew Hayhurst
- Department of Virology and Immunology, Texas Biomedical Research Institute, San Antonio, TX, United States
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30
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Rao MV, Williams DR, Cocklin S, Loll PJ. Interaction between the AAA + ATPase p97 and its cofactor ataxin3 in health and disease: Nucleotide-induced conformational changes regulate cofactor binding. J Biol Chem 2017; 292:18392-18407. [PMID: 28939772 DOI: 10.1074/jbc.m117.806281] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 09/16/2017] [Indexed: 12/29/2022] Open
Abstract
p97 is an essential ATPase associated with various cellular activities (AAA+) that functions as a segregase in diverse cellular processes, including the maintenance of proteostasis. p97 interacts with different cofactors that target it to distinct pathways; an important example is the deubiquitinase ataxin3, which collaborates with p97 in endoplasmic reticulum-associated degradation. However, the molecular details of this interaction have been unclear. Here, we characterized the binding of ataxin3 to p97, showing that ataxin3 binds with low-micromolar affinity to both wild-type p97 and mutants linked to degenerative disorders known as multisystem proteinopathy 1 (MSP1); we further showed that the stoichiometry of binding is one ataxin3 molecule per p97 hexamer. We mapped the binding determinants on each protein, demonstrating that ataxin3's p97/VCP-binding motif interacts with the inter-lobe cleft in the N-domain of p97. We also probed the nucleotide dependence of this interaction, confirming that ataxin3 and p97 associate in the presence of ATP and in the absence of nucleotide, but not in the presence of ADP. Our experiments suggest that an ADP-driven downward movement of the p97 N-terminal domain dislodges ataxin3 by inducing a steric clash between the D1-domain and ataxin3's C terminus. In contrast, MSP1 mutants of p97 bind ataxin3 irrespective of their nucleotide state, indicating a failure by these mutants to translate ADP binding into a movement of the N-terminal domain. Our model provides a mechanistic explanation for how nucleotides regulate the p97-ataxin3 interaction and why atypical cofactor binding is observed with MSP1 mutants.
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Affiliation(s)
- Maya V Rao
- From the Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102 and
| | - Dewight R Williams
- the LeRoy Eyring Center for Solid State Science, Arizona State University, Tempe, Arizona 85287
| | - Simon Cocklin
- From the Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102 and
| | - Patrick J Loll
- From the Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania 19102 and
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Wang W, MacKinnon R. Cryo-EM Structure of the Open Human Ether-à-go-go-Related K + Channel hERG. Cell 2017; 169:422-430.e10. [PMID: 28431243 DOI: 10.1016/j.cell.2017.03.048] [Citation(s) in RCA: 353] [Impact Index Per Article: 50.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 03/01/2017] [Accepted: 03/30/2017] [Indexed: 11/17/2022]
Abstract
The human ether-à-go-go-related potassium channel (hERG, Kv11.1) is a voltage-dependent channel known for its role in repolarizing the cardiac action potential. hERG alteration by mutation or pharmacological inhibition produces Long QT syndrome and the lethal cardiac arrhythmia torsade de pointes. We have determined the molecular structure of hERG to 3.8 Å using cryo-electron microscopy. In this structure, the voltage sensors adopt a depolarized conformation, and the pore is open. The central cavity has an atypically small central volume surrounded by four deep hydrophobic pockets, which may explain hERG's unusual sensitivity to many drugs. A subtle structural feature of the hERG selectivity filter might correlate with its fast inactivation rate, which is key to hERG's role in cardiac action potential repolarization.
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Affiliation(s)
- Weiwei Wang
- Laboratory of Molecular Neurobiology and Biophysics, The Rockefeller University and Howard Hughes Medical Institute, 1230 York Avenue, New York, NY 10065, USA
| | - Roderick MacKinnon
- Laboratory of Molecular Neurobiology and Biophysics, The Rockefeller University and Howard Hughes Medical Institute, 1230 York Avenue, New York, NY 10065, USA.
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Trieu MM, Devine EL, Lamarche LB, Ammerman AE, Greco JA, Birge RR, Theobald DL, Oprian DD. Expression, purification, and spectral tuning of RhoGC, a retinylidene/guanylyl cyclase fusion protein and optogenetics tool from the aquatic fungus Blastocladiella emersonii. J Biol Chem 2017; 292:10379-10389. [PMID: 28473465 DOI: 10.1074/jbc.m117.789636] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 05/03/2017] [Indexed: 02/03/2023] Open
Abstract
RhoGC is a rhodopsin (Rho)-guanylyl cyclase (GC) gene fusion molecule that is central to zoospore phototaxis in the aquatic fungus Blastocladiella emersonii It has generated considerable excitement because of its demonstrated potential as a tool for optogenetic manipulation of cell-signaling pathways involving cyclic nucleotides. However, a reliable method for expressing and purifying RhoGC is currently lacking. We present here an expression and purification system for isolation of the full-length RhoGC protein expressed in HEK293 cells in detergent solution. The protein exhibits robust light-dependent guanylyl cyclase activity, whereas a truncated form lacking the 17- to 20-kDa N-terminal domain is completely inactive under identical conditions. Moreover, we designed several RhoGC mutants to increase the utility of the protein for optogenetic studies. The first class we generated has altered absorption spectra designed for selective activation by different wavelengths of light. Two mutants were created with blue-shifted (E254D, λmax = 390 nm; D380N, λmax = 506 nm) and one with red-shifted (D380E, λmax = 533 nm) absorption maxima relative to the wild-type protein (λmax = 527 nm). We also engineered a double mutant, E497K/C566D, that changes the enzyme to a specific, light-stimulated adenylyl cyclase that catalyzes the formation of cAMP from ATP. We anticipate that this expression/purification system and these RhoGC mutants will facilitate mechanistic and structural exploration of this important enzyme.
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Affiliation(s)
- Melissa M Trieu
- From the Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454 and
| | - Erin L Devine
- From the Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454 and
| | - Lindsey B Lamarche
- From the Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454 and
| | - Aaron E Ammerman
- From the Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454 and
| | - Jordan A Greco
- the Departments of Chemistry and Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269
| | - Robert R Birge
- the Departments of Chemistry and Molecular and Cell Biology, University of Connecticut, Storrs, Connecticut 06269
| | - Douglas L Theobald
- From the Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454 and
| | - Daniel D Oprian
- From the Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02454 and
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33
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Hofrnann L, Alexander NS, Sun W, Zhang J, Orban T, Palczewski K. Hydrogen/Deuterium Exchange Mass Spectrometry of Human Green Opsin Reveals a Conserved Pro-Pro Motif in Extracellular Loop 2 of Monostable Visual G Protein-Coupled Receptors. Biochemistry 2017; 56:2338-2348. [PMID: 28402104 PMCID: PMC5501310 DOI: 10.1021/acs.biochem.7b00165] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Opsins comprise the protein component of light sensitive G protein-coupled receptors (GPCRs) in the retina of the eye that are responsible for the transduction of light into a biochemical signal. Here, we used hydrogen/deuterium (H/D) exchange coupled with mass spectrometry to map conformational changes in green cone opsin upon light activation. We then compared these findings with those reported for rhodopsin. The extent of H/D exchange in green cone opsin was greater than in rhodopsin in the dark and bleached states, suggesting a higher structural heterogeneity for green cone opsin. Further analysis revealed that green cone opsin exists as a dimer in both dark (inactive) and bleached (active) states, and that the predicted glycosylation sites at N32 and N34 are indeed glycosylated. Comparison of deuterium uptake between inactive and active states of green cone opsin also disclosed a reduced solvent accessibility of the extracellular N-terminal region and an increased accessibility of the chromophore binding site. Increased H/D exchange at the extracellular side of transmembrane helix four (TM4) combined with an analysis of sequence alignments revealed a conserved Pro-Pro motif in extracellular loop 2 (EL2) of monostable visual GPCRs. These data present new insights into the locus of chromophore release at the extracellular side of TM4 and TM5 and provide a foundation for future functional evaluation.
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Affiliation(s)
- Lukas Hofrnann
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Nathan S. Alexander
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Wenyu Sun
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Jianye Zhang
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Tivadar Orban
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Krzysztof Palczewski
- Department of Pharmacology and Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
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Yeliseev A, Zoubak L, Schmidt TGM. Application of Strep-Tactin XT for affinity purification of Twin-Strep-tagged CB 2, a G protein-coupled cannabinoid receptor. Protein Expr Purif 2017; 131:109-118. [PMID: 27867058 PMCID: PMC5406253 DOI: 10.1016/j.pep.2016.11.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 11/02/2016] [Accepted: 11/04/2016] [Indexed: 11/29/2022]
Abstract
Human cannabinoid receptor CB2 belongs to the class A of G protein-coupled receptor (GPCR). CB2 is predominantly expressed in membranes of cells of immune origin and is implicated in regulation of metabolic pathways of inflammation, neurodegenerative disorders and pain sensing. High resolution structural studies of CB2 require milligram quantities of purified, structurally intact protein. While we previously reported on the methodology for expression of the recombinant CB2 and its stabilization in a functional state, here we describe an efficient protocol for purification of this protein using the Twin-Strep-tag/Strep-Tactin XT system. To improve the affinity of interaction of the recombinant CB2 with the resin, the double repeat of the Strep-tag (a sequence of eight amino acids WSHPQFEK), named the Twin-Strep-tag was attached either to the N- or C-terminus of CB2 via a short linker, and the recombinant protein was expressed in cytoplasmic membranes of E. coli as a fusion with the N-terminal maltose binding protein (MBP). The CB2 was isolated at high purity from dilute solutions containing high concentrations of detergents, glycerol and salts, by capturing onto the Strep-Tactin XT resin, and was eluted from the resin under mild conditions upon addition of biotin. Surface plasmon resonance studies performed on the purified protein demonstrate the high affinity of interaction between the Twin-Strep-tag fused to the CB2 and Strep-Tactin XT with an estimated Kd in the low nanomolar range. The affinity of binding did not vary significantly in response to the position of the tag at either N- or C-termini of the fusion. The binding capacity of the resin was several-fold higher for the tag located at the N-terminus of the protein as opposed to the C-terminus- or middle of the fusion. The variation in the length of the linker between the double repeats of the Strep-tag from 6 to 12 amino acid residues did not significantly affect the binding. The novel purification protocol reported here enables efficient isolation of a recombinant GPCR expressed at low titers in host cells. This procedure is suitable for preparation of milligram quantities of stable isotope-labelled receptor for high-resolution NMR studies.
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MESH Headings
- Chromatography, Affinity/methods
- Escherichia coli
- Gene Expression
- Humans
- Nuclear Magnetic Resonance, Biomolecular
- Receptor, Cannabinoid, CB2/biosynthesis
- Receptor, Cannabinoid, CB2/chemistry
- Receptor, Cannabinoid, CB2/genetics
- Receptor, Cannabinoid, CB2/isolation & purification
- Recombinant Fusion Proteins/biosynthesis
- Recombinant Fusion Proteins/chemistry
- Recombinant Fusion Proteins/genetics
- Recombinant Fusion Proteins/isolation & purification
- Surface Plasmon Resonance
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Affiliation(s)
- Alexei Yeliseev
- National Institute on Alcoholism and Alcohol Abuse, National Institutes of Health, 5625 Fishers Lane, Room 3N17, Rockville, MD, 20892, USA.
| | - Lioudmila Zoubak
- National Institute on Alcoholism and Alcohol Abuse, National Institutes of Health, 5625 Fishers Lane, Room 3N17, Rockville, MD, 20892, USA
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35
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Liao H, Ren X, Peterson BB, Marshak DW, Yau K, Gamlin PD, Dacey DM. Melanopsin-expressing ganglion cells on macaque and human retinas form two morphologically distinct populations. J Comp Neurol 2016; 524:2845-72. [PMID: 26972791 PMCID: PMC4970949 DOI: 10.1002/cne.23995] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 01/30/2016] [Accepted: 03/07/2016] [Indexed: 12/20/2022]
Abstract
The long-term goal of this research is to understand how retinal ganglion cells that express the photopigment melanopsin, also known as OPN4, contribute to vision in humans and other primates. Here we report the results of anatomical studies using our polyclonal antibody specifically against human melanopsin that confirm and extend previous descriptions of melanopsin cells in primates. In macaque and human retina, two distinct populations of melanopsin cells were identified based on dendritic stratification in either the inner or the outer portion of the inner plexiform layer (IPL). Variation in dendritic field size and cell density with eccentricity was confirmed, and dendritic spines, a new feature of melanopsin cells, were described. The spines were the sites of input from DB6 diffuse bipolar cell axon terminals to the inner stratifying type of melanopsin cells. The outer stratifying melanopsin type received inputs from DB6 bipolar cells via a sparse outer axonal arbor. Outer stratifying melanopsin cells also received inputs from axon terminals of dopaminergic amacrine cells. On the outer stratifying melanopsin cells, ribbon synapses from bipolar cells and conventional synapses from amacrine cells were identified in electron microscopic immunolabeling experiments. Both inner and outer stratifying melanopsin cell types were retrogradely labeled following tracer injection in the lateral geniculate nucleus (LGN). In addition, a method for targeting melanopsin cells for intracellular injection using their intrinsic fluorescence was developed. This technique was used to demonstrate that melanopsin cells were tracer coupled to amacrine cells and would be applicable to electrophysiological experiments in the future. J. Comp. Neurol. 524:2845-2872, 2016. © 2016 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Hsi‐Wen Liao
- Department of NeuroscienceJohn Hopkins University School of MedicineBaltimoreMaryland21205‐2185
| | - Xiaozhi Ren
- Department of NeuroscienceJohn Hopkins University School of MedicineBaltimoreMaryland21205‐2185
| | - Beth B. Peterson
- Department of Biological StructureUniversity of Washington and the Washington National Primate Research CenterSeattleWashington98195‐7420
| | - David W. Marshak
- Department of Neurobiology and AnatomyUniversity of Texas Medical SchoolHoustonTexas77030
| | - King‐Wai Yau
- Department of NeuroscienceJohn Hopkins University School of MedicineBaltimoreMaryland21205‐2185
- Department of OphthalmologyJohn Hopkins University School of MedicineBaltimoreMaryland21205‐2185
| | - Paul D. Gamlin
- Department of OphthalmologyUniversity of Alabama at BirminghamBirminghamAlabama35294
| | - Dennis M. Dacey
- Department of Biological StructureUniversity of Washington and the Washington National Primate Research CenterSeattleWashington98195‐7420
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