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Huang M, Zheng M, Song Q, Ma X, Zhang Q, Chen H, Jiang G, Zhou S, Chen H, Wang G, Dai C, Li S, Li P, Wang H, Zhang A, Huang Y, Chen J, Gao X. Comparative Proteomics Inspired Self-Stimulated Release Hydrogel Reinforces the Therapeutic Effects of MSC-EVs on Alzheimer's Disease. Adv Mater 2024; 36:e2311420. [PMID: 38157492 DOI: 10.1002/adma.202311420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 12/10/2023] [Indexed: 01/03/2024]
Abstract
The clinical application of extracellular vesicles (EVs)-based therapeutics continues to be challenging due to their rapid clearance, restricted retention, and low yields. Although hydrogel possesses the ability to impede physiological clearance and increase regional retention, it typically fails to effectively release the incorporated EVs, resulting in reduced accessibility and bioavailability. Here an intelligent hydrogel in which the release of EVs is regulated by the proteins on the EVs membrane is proposed. By utilizing the EVs membrane enzyme to facilitate hydrogel degradation, sustained retention and self-stimulated EVs release can be achieved at the administration site. To achieve this goal, the membrane proteins with matrix degrading activity in the mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are identified using comparative proteomics. After that, a hydrogel comprised of self-assembled peptides that are susceptible to degradation by the membrane enzymes present in MSC-EVs is designed and synthesized. After intranasal administration, this peptide hydrogel facilitates sustained and thermo-sensitive release of MSC-EVs, thereby extending the retention of the MSC-EVs and substantially enhancing their potential for treating Alzheimer's disease. This research presents a comparative proteomics-driven approach to intelligent hydrogel design, which holds the capacity to significantly enhance the applicability of EVs in clinical settings.
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Affiliation(s)
- Meng Huang
- Department of Pharmacology and Chemical Biology, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Mengna Zheng
- Department of Pharmacology and Chemical Biology, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Qingxiang Song
- Department of Pharmacology and Chemical Biology, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Xinyi Ma
- Department of Pharmacology and Chemical Biology, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Qian Zhang
- Department of Pharmacology and Chemical Biology, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Huan Chen
- Department of Pharmacology and Chemical Biology, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Gan Jiang
- Department of Pharmacology and Chemical Biology, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Songlei Zhou
- Department of Pharmacy, Shanghai Pudong Hospital, Fudan University, 2800 Gongwei Road, Shanghai, 201399, China
| | - Hongzhuan Chen
- Institute of Interdisciplinary Integrative Biomedical Research, Shuguang Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, 201203, China
| | - Gang Wang
- Department of Neurology and Institute of Neurology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Chengxiang Dai
- Daxing Research Institute, University of Science and Technology Beijing, Beijing, 102600, China
| | - Suke Li
- Cellular Biomedicine Group Inc, Shanghai, 201210, China
| | - Ping Li
- Cellular Biomedicine Group Inc, Shanghai, 201210, China
| | - Hao Wang
- Department of Pharmacology and Chemical Biology, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Ao Zhang
- School of Pharmaceutical Sciences, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Yukun Huang
- Department of Pharmacology and Chemical Biology, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jun Chen
- Department of Pharmacy, Shanghai Pudong Hospital, Fudan University, 2800 Gongwei Road, Shanghai, 201399, China
| | - Xiaoling Gao
- Department of Pharmacology and Chemical Biology, Shanghai Universities Collaborative Innovation Center for Translational Medicine, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
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2
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Shokhen M, Albeck A. How does the exosite of rhomboid protease affect substrate processing and inhibition? Protein Sci 2017; 26:2355-2366. [PMID: 28884847 DOI: 10.1002/pro.3294] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 08/27/2017] [Accepted: 09/03/2017] [Indexed: 12/24/2022]
Abstract
Rhomboid proteases constitute a family of intramembrane serine proteases ubiquitous in all forms of life. They differ in many aspects from their soluble counterparts. We applied molecular dynamics (MD) computational approach to address several challenging issues regarding their catalytic mechanism: How does the exosite of GlpG rhomboid protease control the kinetics efficiency of substrate hydrolysis? What is the mechanism of inhibition by the non-competitive peptidyl aldehyde inhibitors bound to the GlpG rhomboid active site (AS)? What is the underlying mechanism that explains the hypothesis that GlpG rhomboid protease is not adopted for the hydrolysis of short peptides that do not contain a transmembrane domain (TMD)? Two fundamental features of rhomboid catalysis, the enzyme recognition and discrimination of substrates by TMD interactions in the exosite, and the concerted mechanism of non-covalent pre-catalytic complex to covalent tetrahedral complex (TC) conversion, provide answers to these mechanistic questions.
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Affiliation(s)
- Michael Shokhen
- The Julius Spokojny Bioorganic Chemistry Laboratory, Department of Chemistry, Bar Ilan University, Ramat Gan, 5290002, Israel
| | - Amnon Albeck
- The Julius Spokojny Bioorganic Chemistry Laboratory, Department of Chemistry, Bar Ilan University, Ramat Gan, 5290002, Israel
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3
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Wadsäter M, Laursen T, Singha A, Hatzakis NS, Stamou D, Barker R, Mortensen K, Feidenhans'l R, Møller BL, Cárdenas M. Monitoring shifts in the conformation equilibrium of the membrane protein cytochrome P450 reductase (POR) in nanodiscs. J Biol Chem 2012; 287:34596-603. [PMID: 22891242 PMCID: PMC3464565 DOI: 10.1074/jbc.m112.400085] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 08/09/2012] [Indexed: 11/06/2022] Open
Abstract
Nanodiscs are self-assembled ∼50-nm(2) patches of lipid bilayers stabilized by amphipathic belt proteins. We demonstrate that a well ordered dense film of nanodiscs serves for non-destructive, label-free studies of isolated membrane proteins in a native like environment using neutron reflectometry (NR). This method exceeds studies of membrane proteins in vesicle or supported lipid bilayer because membrane proteins can be selectively adsorbed with controlled orientation. As a proof of concept, the mechanism of action of the membrane-anchored cytochrome P450 reductase (POR) is studied here. This enzyme is responsible for catalyzing the transfer of electrons from NADPH to cytochrome P450s and thus is a key enzyme in the biosynthesis of numerous primary and secondary metabolites in plants. Neutron reflectometry shows a coexistence of two different POR conformations, a compact and an extended form with a thickness of 44 and 79 Å, respectively. Upon complete reduction by NADPH, the conformational equilibrium shifts toward the compact form protecting the reduced FMN cofactor from engaging in unspecific electron transfer reaction.
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Affiliation(s)
- Maria Wadsäter
- From the Nano-Science Center and Institute of Chemistry, Faculty of Science, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Tomas Laursen
- the Plant Biochemistry Laboratory, Department of Plant and Environmental Science, Faculty of Science, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Aparajita Singha
- the Bio-Nanotechnology Laboratory, Department of Neuroscience and Pharmacology, Nano-Science Center, Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Nikos S. Hatzakis
- the Bio-Nanotechnology Laboratory, Department of Chemistry, Department of Neuroscience and Pharmacology, Nano-Science Center, Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Dimitrios Stamou
- the Bio-Nanotechnology Laboratory, Department of Chemistry, Department of Neuroscience and Pharmacology, Nano-Science Center, Lundbeck Foundation Center Biomembranes in Nanomedicine, University of Copenhagen, 2100 Copenhagen, Denmark
| | - Robert Barker
- the Institut Laue Langevin, 6 rue Jules Horowitz – BP 156, 38042 Grenoble Cedex 9, France, and
| | - Kell Mortensen
- the Nano-Science Center and Niels Bohr Institute, Universitetsparken 5, 2200 Copenhagen, Denmark
| | - Robert Feidenhans'l
- the Nano-Science Center and Niels Bohr Institute, Universitetsparken 5, 2200 Copenhagen, Denmark
| | - Birger Lindberg Møller
- the Plant Biochemistry Laboratory, Department of Plant and Environmental Science, Faculty of Science, University of Copenhagen, DK-1871 Frederiksberg C, Denmark
| | - Marité Cárdenas
- From the Nano-Science Center and Institute of Chemistry, Faculty of Science, University of Copenhagen, DK-2200 Copenhagen, Denmark
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Schröder HC, Wang X, Manfrin A, Yu SH, Grebenjuk VA, Korzhev M, Wiens M, Schlossmacher U, Müller WEG. Acquisition of structure-guiding and structure-forming properties during maturation from the pro-silicatein to the silicatein form. J Biol Chem 2012; 287:22196-205. [PMID: 22544742 PMCID: PMC3381181 DOI: 10.1074/jbc.m112.351486] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 04/05/2012] [Indexed: 11/06/2022] Open
Abstract
Silicateins are the key enzymes involved in the enzymatic polycondensation of the inorganic scaffold of the skeletal elements of the siliceous sponges, the spicules. The gene encoding pro-silicatein is inserted into the pCold TF vector, comprising the gene for the bacterial trigger factor. This hybrid gene is expressed in Escherichia coli and the synthesized fusion protein is purified. The fusion protein is split into the single proteins with thrombin by cleavage of the linker sequence present between the two proteins. At 23 °C, the 87 kDa trigger factor-pro-silicatein fusion protein is cleaved to the 51 kDa trigger factor and the 35 kDa pro-silicatein. The cleavage process proceeds and results in the release of the 23 kDa mature silicatein, a process which very likely proceeds by autocatalysis. Almost in parallel with its formation, the mature enzyme precipitates as pure 23 kDa protein. When the precipitate is dissolved in an urea buffer, the solubilized protein displays its full enzymatic activity which is enhanced multi-fold in the presence of the silicatein interactor silintaphin-1 or of poly(ethylene glycol) (PEG). The biosilica product formed increases its compactness if silicatein is supplemented with silintaphin-1 or PEG. The elastic modulus of the silicatein-mediated biosilica product increases in parallel with the addition of silintaphin-1 and/or PEG from 17 MPa (silicatein) via 61 MPa (silicatein:silintaphin-1) to 101 MPa (silicatein:silintaphin-1 and PEG). These data show that the maturation process from the pro-silicatein state to the mature form is the crucial step during which silicatein acquires its structure-guiding and structure-forming properties.
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Affiliation(s)
- Heinz C. Schröder
- From the ERC Advanced Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
| | - Xiaohong Wang
- From the ERC Advanced Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
- the National Research Center for Geoanalysis, Chinese Academy of Geological Sciences, Beijing 100037, China, and
| | - Alberto Manfrin
- From the ERC Advanced Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
| | - Shu-Hong Yu
- the The Cheung Kong Chair Professor, Division of Nanomaterials & Chemistry, University of Science and Technology of China, Hefei 230026, China
| | - Vlad A. Grebenjuk
- From the ERC Advanced Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
| | - Michael Korzhev
- From the ERC Advanced Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
| | - Matthias Wiens
- From the ERC Advanced Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
| | - Ute Schlossmacher
- From the ERC Advanced Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
| | - Werner E. G. Müller
- From the ERC Advanced Grant Research Group at the Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, D-55128 Mainz, Germany
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5
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Rogers MA, Liu J, Kushnir MM, Bryleva E, Rockwood AL, Meikle AW, Shapiro D, Vaisman BL, Remaley AT, Chang CCY, Chang TY. Cellular pregnenolone esterification by acyl-CoA:cholesterol acyltransferase. J Biol Chem 2012; 287:17483-17492. [PMID: 22474282 PMCID: PMC3366839 DOI: 10.1074/jbc.m111.331306] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 03/28/2012] [Indexed: 11/06/2022] Open
Abstract
Pregnenolone (PREG) can be converted to PREG esters (PE) by the plasma enzyme lecithin: cholesterol acyltransferase (LCAT), and by other enzyme(s) with unknown identity. Acyl-CoA:cholesterol acyltransferase 1 and 2 (ACAT1 and ACAT2) convert various sterols to steryl esters; their activities are activated by cholesterol. PREG is a sterol-like molecule, with 3-β-hydroxy moiety at steroid ring A, but with much shorter side chain at steroid ring D. Here we show that without cholesterol, PREG is a poor ACAT substrate; with cholesterol, the V(max) for PREG esterification increases by 100-fold. The binding affinity of ACAT1 for PREG is 30-50-fold stronger than that for cholesterol; however, PREG is only a substrate but not an activator, while cholesterol is both a substrate and an activator. These results indicate that the sterol substrate site in ACAT1 does not involve significant sterol-phospholipid interaction, while the sterol activator site does. Studies utilizing small molecule ACAT inhibitors show that ACAT plays a key role in PREG esterification in various cell types examined. Mice lacking ACAT1 or ACAT2 do not have decreased PREG ester contents in adrenals, nor do they have altered levels of the three major secreted adrenal steroids in serum. Mice lacking LCAT have decreased levels of PREG esters in the adrenals. These results suggest LCAT along with ACAT1/ACAT2 contribute to control pregnenolone ester content in different cell types and tissues.
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Affiliation(s)
- Maximillian A Rogers
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755
| | - Jay Liu
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755
| | - Mark M Kushnir
- ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, Utah 84108; Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah 84112
| | - Elena Bryleva
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755
| | - Alan L Rockwood
- ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, Utah 84108; Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah 84112
| | - A Wayne Meikle
- ARUP Institute for Clinical and Experimental Pathology, Salt Lake City, Utah 84108; Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah 84112
| | - David Shapiro
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755
| | - Boris L Vaisman
- Lipoprotein Metabolism Section,Cardiovascular-Pulmonary Branch, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Alan T Remaley
- Lipoprotein Metabolism Section,Cardiovascular-Pulmonary Branch, NHLBI, National Institutes of Health, Bethesda, Maryland 20892
| | - Catherine C Y Chang
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755.
| | - Ta-Yuan Chang
- Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755.
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6
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Tidhar R, Ben-Dor S, Wang E, Kelly S, Merrill AH, Futerman AH. Acyl chain specificity of ceramide synthases is determined within a region of 150 residues in the Tram-Lag-CLN8 (TLC) domain. J Biol Chem 2012; 287:3197-206. [PMID: 22144673 PMCID: PMC3270974 DOI: 10.1074/jbc.m111.280271] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 11/26/2011] [Indexed: 12/15/2022] Open
Abstract
In mammals, ceramides are synthesized by a family of six ceramide synthases (CerS), transmembrane proteins located in the endoplasmic reticulum, where each use fatty acyl-CoAs of defined chain length for ceramide synthesis. Little is known about the molecular features of the CerS that determine acyl-CoA selectivity. We now explore CerS structure-function relationships by constructing chimeric proteins combining sequences from CerS2, which uses C22-CoA for ceramide synthesis, and CerS5, which uses C16-CoA. CerS2 and -5 are 41% identical and 63% similar. Chimeras containing approximately half of CerS5 (from the N terminus) and half of CerS2 (from the C terminus) were catalytically inactive. However, the first 158 residues of CerS5 could be replaced with the equivalent region of CerS2 without affecting specificity of CerS5 toward C16-CoA; likewise, the putative sixth transmembrane domain (at the C terminus) of CerS5 could be replaced with the corresponding sequence of CerS2 without affecting CerS5 specificity. Remarkably, a chimeric CerS5/2 protein containing the first 158 residues and the last 83 residues of CerS2 displayed specificity toward C16-CoA, and a chimeric CerS2/5 protein containing the first 150 residues and the last 79 residues of CerS5 displayed specificity toward C22-CoA, demonstrating that a minimal region of 150 residues is sufficient for retaining CerS specificity.
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Affiliation(s)
- Rotem Tidhar
- From the Departments of Biological Chemistry and
| | - Shifra Ben-Dor
- Biological Services, Weizmann Institute of Science, Rehovot 76100, Israel and
| | - Elaine Wang
- the School of Biology and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332-0230
| | - Samuel Kelly
- the School of Biology and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332-0230
| | - Alfred H. Merrill
- the School of Biology and Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, Georgia 30332-0230
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7
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Li Y, Martin BR, Cravatt BF, Hofmann SL. DHHC5 protein palmitoylates flotillin-2 and is rapidly degraded on induction of neuronal differentiation in cultured cells. J Biol Chem 2012; 287:523-530. [PMID: 22081607 PMCID: PMC3249106 DOI: 10.1074/jbc.m111.306183] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 11/07/2011] [Indexed: 01/20/2023] Open
Abstract
Post-translational palmitoylation of intracellular proteins is mediated by protein palmitoyltransferases belonging to the DHHC family, which share a common catalytic Asp-His-His-Cys (DHHC) motif. Several members have been implicated in neuronal development, neurotransmission, and synaptic plasticity. We previously observed that mice homozygous for a hypomorphic allele of the ZDHHC5 gene are impaired in context-dependent learning and memory. To identify potentially relevant protein substrates of DHHC5, we performed a quantitative proteomic analysis of stable isotope-labeled neuronal stem cell cultures from forebrains of normal and DHHC5-GT (gene-trapped) mice using the bioorthogonal palmitate analog 17-octadecynoic acid. We identified ∼300 17-octadecynoic acid-modified and hydroxylamine-sensitive proteins, of which a subset was decreased in abundance in DHHC5-GT cells. Palmitoylation and oligomerization of one of these proteins (flotillin-2) was abolished in DHHC5-GT neuronal stem cells. In COS-1 cells, overexpression of DHHC5 markedly stimulated the palmitoylation of flotillin-2, strongly suggesting a direct enzyme-substrate relationship. Serendipitously, we found that down-regulation of DHHC5 was triggered within minutes following growth factor withdrawal from normal neural stem cells, a maneuver that is used to induce neural differentiation in culture. The effect was reversible for up to 4 h, and degradation was partially prevented by inhibitors of ubiquitin-mediated proteolysis. These findings suggest that protein palmitoylation can be regulated through changes in DHHC PAT levels in response to differentiation signals.
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Affiliation(s)
- Yi Li
- Hamon Center for Therapeutic Oncology Research and Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-8593
| | - Brent R Martin
- Skaggs Institute of Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037
| | - Benjamin F Cravatt
- Skaggs Institute of Chemical Biology and Department of Chemical Physiology, The Scripps Research Institute, La Jolla, California 92037
| | - Sandra L Hofmann
- Hamon Center for Therapeutic Oncology Research and Department of Internal Medicine, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-8593.
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8
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Liu Q, Siloto RMP, Snyder CL, Weselake RJ. Functional and topological analysis of yeast acyl-CoA:diacylglycerol acyltransferase 2, an endoplasmic reticulum enzyme essential for triacylglycerol biosynthesis. J Biol Chem 2011; 286:13115-26. [PMID: 21321129 PMCID: PMC3075658 DOI: 10.1074/jbc.m110.204412] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Revised: 02/01/2011] [Indexed: 11/06/2022] Open
Abstract
Acyl-CoA:diacylglycerol acyltransferase (EC 2.3.1.20) is a membrane protein present mainly in the endoplasmic reticulum. It catalyzes the final and committed step in the biosynthesis of triacylglycerol, which is the principal repository of fatty acids for energy utilization and membrane formation. Two distinct family members of acyl-CoA:diacylglycerol acyltransferase, known as DGAT1 and DGAT2, have been characterized in different organisms, including mammals, fungi, and plants. In this study, we characterized the functional role and topological orientation of signature motifs in yeast (Saccharomyces cerevisiae) DGAT2 using mutagenesis in conjunction with chemical modification. Our data provide evidence that both the N and C termini are oriented toward the cytosol and have different catalytic roles. A highly conserved motif, (129)YFP(131), and a hydrophilic segment exclusive to yeast DGAT2 reside in a long endoplasmic reticulum luminal loop following the first transmembrane domain and play an essential role in enzyme catalysis. In addition, the strongly conserved His(195) within the motif HPHG, which may play a role in the active site of DGAT2, is likely embedded in the membrane. These results indicate some similarities to the topology model of murine DGAT2 but also reveal striking differences suggesting that the topological organization of DGAT2 is not ubiquitously conserved.
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Affiliation(s)
- Qin Liu
- From the Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Rodrigo M. P. Siloto
- From the Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Crystal L. Snyder
- From the Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
| | - Randall J. Weselake
- From the Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada
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9
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Karki P, Li X, Schrama D, Fliegel L. B-Raf associates with and activates the NHE1 isoform of the Na+/H+ exchanger. J Biol Chem 2011; 286:13096-105. [PMID: 21345796 PMCID: PMC3075656 DOI: 10.1074/jbc.m110.165134] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 02/03/2011] [Indexed: 01/03/2023] Open
Abstract
The serine/threonine kinase B-Raf is the second most frequently occurring human oncogene after Ras. Mutations of B-Raf occur with the highest incidences in melanoma, and the most common mutant, V600E, renders B-Raf constitutively active. The sodium proton exchanger isoform 1 (NHE1) is a ubiquitously expressed plasma membrane protein responsible for regulating intracellular pH, cell volume, cell migration, and proliferation. A screen of protein kinases that bind to NHE1 revealed that B-Raf bound to the cytosolic regulatory tail of NHE1. Immunoprecipitation of NHE1 from HeLa and HEK cells confirmed the association of B-Raf with NHE1 in vivo. The expressed and purified C-terminal 182 amino acids of the NHE1 protein were also shown to associate with B-Raf protein in vitro. Because treatment with the kinase inhibitor sorafenib decreased NHE1 activity in HeLa and HEK cells, we examined the role of B-Raf in regulating NHE1 in malignant melanoma cells. Melanoma cells with the B-Raf(V600E) mutation demonstrated increased resting intracellular pH that was dependent on elevated NHE1 activity. NHE1 activity after an acute acid load was also elevated in these cell lines. Moreover, inhibition of B-Raf activity by either sorafenib, PLX4720, or siRNA reduction of B-Raf levels abolished ERK phosphorylation and decreased NHE1 activity. These results demonstrate that B-Raf associates with and stimulates NHE1 activity and that B-Raf(V600E) also increases NHE1 activity that raises intracellular pH.
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Affiliation(s)
- Pratap Karki
- From the Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada and
| | - Xiuju Li
- From the Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada and
| | - David Schrama
- the Division of Dermatology, Medical University of Graz, 8036 Graz, Austria
| | - Larry Fliegel
- From the Department of Biochemistry, University of Alberta, Edmonton, Alberta T6G 2H7, Canada and
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10
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Jiang J, Wu S, Wang W, Chen S, Peng J, Zhang X, Wu Q. Ectodomain shedding and autocleavage of the cardiac membrane protease corin. J Biol Chem 2011; 286:10066-72. [PMID: 21288900 PMCID: PMC3060458 DOI: 10.1074/jbc.m110.185082] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 01/21/2011] [Indexed: 11/06/2022] Open
Abstract
Corin is a cardiac membrane protease that activates natriuretic peptides. It is unknown how corin function is regulated. Recently, soluble corin was detected in human plasma, suggesting that corin may be shed from cardiomyocytes. Here we examined soluble corin production and activity and determined the proteolytic enzymes responsible for corin cleavage. We expressed human corin in HEK 293 cells and detected three soluble fragments of ∼180, ∼160, and ∼100 kDa, respectively, in the cultured medium by Western blot analysis. All three fragments were derived from activated corin molecules. Similar results were obtained in HL-1 cardiomyocytes. Using protease inhibitors, ionomycin and phorbol myristate acetate stimulation, small interfering RNA knockdown, and site-directed mutagenesis, we found that ADAM10 was primarily responsible for shedding corin in its juxtamembrane region to release the ∼180-kDa fragment, corresponding to the near-entire extracellular region. In contrast, the ∼160- and ∼100-kDa fragments were from corin autocleavage at Arg-164 in frizzled 1 domain and Arg-427 in LDL receptor 5 domain, respectively. In functional studies, the ∼180-kDa fragment activated atrial natriuretic peptide, whereas the ∼160- and ∼100-kDa fragments did not. Our data indicate that ADAM-mediated shedding and corin autocleavage are important mechanisms regulating corin function and preventing excessive, potentially hazardous, proteolytic activities in the heart.
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Affiliation(s)
- Jingjing Jiang
- From the Department of Molecular Cardiology, Nephrology, and Hypertension, Cleveland Clinic, Cleveland, Ohio 44195 and
- the Department of Pharmacology, Shandong University Medical School, Jinan 250012, China, and
| | - Shannon Wu
- From the Department of Molecular Cardiology, Nephrology, and Hypertension, Cleveland Clinic, Cleveland, Ohio 44195 and
| | - Wei Wang
- From the Department of Molecular Cardiology, Nephrology, and Hypertension, Cleveland Clinic, Cleveland, Ohio 44195 and
| | - Shenghan Chen
- From the Department of Molecular Cardiology, Nephrology, and Hypertension, Cleveland Clinic, Cleveland, Ohio 44195 and
| | - Jianhao Peng
- From the Department of Molecular Cardiology, Nephrology, and Hypertension, Cleveland Clinic, Cleveland, Ohio 44195 and
| | - Xiumei Zhang
- the Department of Pharmacology, Shandong University Medical School, Jinan 250012, China, and
| | - Qingyu Wu
- From the Department of Molecular Cardiology, Nephrology, and Hypertension, Cleveland Clinic, Cleveland, Ohio 44195 and
- the Cyrus Tang Hematology Center, Jiangsu Institute of Hematology, First Affiliated Hospital, Soochow University, Suzhou 215123, China
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11
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Guerin ME, Korduláková J, Alzari PM, Brennan PJ, Jackson M. Molecular basis of phosphatidyl-myo-inositol mannoside biosynthesis and regulation in mycobacteria. J Biol Chem 2010; 285:33577-83. [PMID: 20801880 PMCID: PMC2962455 DOI: 10.1074/jbc.r110.168328] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Phosphatidyl-myo-inositol mannosides (PIMs) are unique glycolipids found in abundant quantities in the inner and outer membranes of the cell envelope of all Mycobacterium species. They are based on a phosphatidyl-myo-inositol lipid anchor carrying one to six mannose residues and up to four acyl chains. PIMs are considered not only essential structural components of the cell envelope but also the structural basis of the lipoglycans (lipomannan and lipoarabinomannan), all important molecules implicated in host-pathogen interactions in the course of tuberculosis and leprosy. Although the chemical structure of PIMs is now well established, knowledge of the enzymes and sequential events leading to their biosynthesis and regulation is still incomplete. Recent advances in the identification of key proteins involved in PIM biogenesis and the determination of the three-dimensional structures of the essential phosphatidyl-myo-inositol mannosyltransferase PimA and the lipoprotein LpqW have led to important insights into the molecular basis of this pathway.
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Affiliation(s)
- Marcelo E. Guerin
- From the Unidad de Biofisica, Centro Mixto Consejo Superior de Investigaciones Cientificas-Universidad del País Vasco/Euskal Herriko Unibertsitatea (CSIC-UPV/EHU), Barrio Sarriena s/n, Leioa, Bizkaia 48940, Spain
- the Departamento de Bioquímica, Universidad del País Vasco, 48940 País Vasco, Spain
- IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
| | - Jana Korduláková
- the Department of Biochemistry, Faculty of Natural Sciences, Comenius University, Mlynská Dolina, 84215 Bratislava, Slovakia
| | - Pedro M. Alzari
- the Unité de Biochimie Structurale, CNRS URA 2185, Institut Pasteur, 25 rue du Dr. Roux, 75724 Paris Cedex 15, France, and
| | - Patrick J. Brennan
- the Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682
| | - Mary Jackson
- the Mycobacteria Research Laboratories, Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, Colorado 80523-1682
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12
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Castelle C, Ilbert M, Infossi P, Leroy G, Giudici-Orticoni MT. An unconventional copper protein required for cytochrome c oxidase respiratory function under extreme acidic conditions. J Biol Chem 2010; 285:21519-25. [PMID: 20442397 PMCID: PMC2898452 DOI: 10.1074/jbc.m110.131359] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2010] [Revised: 04/30/2010] [Indexed: 11/06/2022] Open
Abstract
Very little is known about the processes used by acidophile organisms to preserve stability and function of respiratory pathways. Here, we reveal a potential strategy of these organisms for protecting and keeping functional key enzymes under extreme conditions. Using Acidithiobacillus ferrooxidans, we have identified a protein belonging to a new cupredoxin subfamily, AcoP, for "acidophile CcO partner," which is required for the cytochrome c oxidase (CcO) function. We show that it is a multifunctional copper protein with at least two roles as follows: (i) as a chaperone-like protein involved in the protection of the Cu(A) center of the CcO complex and (ii) as a linker between the periplasmic cytochrome c and the inner membrane cytochrome c oxidase. It could represent an interesting model for investigating the multifunctionality of proteins known to be crucial in pathways of energy metabolism.
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Affiliation(s)
- Cindy Castelle
- From the Laboratoire de Bioénergétique et Ingénierie des Protéines, IMM-CNRS, 13402 Marseille Cedex 20, France
| | - Marianne Ilbert
- From the Laboratoire de Bioénergétique et Ingénierie des Protéines, IMM-CNRS, 13402 Marseille Cedex 20, France
| | - Pascale Infossi
- From the Laboratoire de Bioénergétique et Ingénierie des Protéines, IMM-CNRS, 13402 Marseille Cedex 20, France
| | - Gisèle Leroy
- From the Laboratoire de Bioénergétique et Ingénierie des Protéines, IMM-CNRS, 13402 Marseille Cedex 20, France
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Sevova ES, Goren MA, Schwartz KJ, Hsu FF, Turk J, Fox BG, Bangs JD. Cell-free synthesis and functional characterization of sphingolipid synthases from parasitic trypanosomatid protozoa. J Biol Chem 2010; 285:20580-7. [PMID: 20457606 PMCID: PMC2898309 DOI: 10.1074/jbc.m110.127662] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 05/03/2010] [Indexed: 11/06/2022] Open
Abstract
The Trypanosoma brucei genome has four highly similar genes encoding sphingolipid synthases (TbSLS1-4). TbSLSs are polytopic membrane proteins that are essential for viability of the pathogenic bloodstream stage of this human protozoan parasite and, consequently, can be considered as potential drug targets. TbSLS4 was shown previously to be a bifunctional sphingomyelin/ethanolamine phosphorylceramide synthase, whereas functions of the others were not characterized. Using a recently described liposome-supplemented cell-free synthesis system, which eliminates complications from background cellular activities, we now unambiguously define the enzymatic specificity of the entire gene family. TbSLS1 produces inositol phosphorylceramide, TbSLS2 produces ethanolamine phosphorylceramide, and TbSLS3 is bifunctional, like TbSLS4. These findings indicate that TbSLS1 is uniquely responsible for synthesis of inositol phosphorylceramide in insect stage parasites, in agreement with published expression array data (17). This approach also revealed that the Trypanosoma cruzi ortholog (TcSLS1) is a dedicated inositol phosphorylceramide synthase. The cell-free synthesis system allowed rapid optimization of the reaction conditions for these enzymes and site-specific mutagenesis to alter end product specificity. A single residue at position 252 (TbSLS1, Ser(252); TbSLS3, Phe(252)) strongly influences enzymatic specificity. We also have used this system to demonstrate that aureobasidin A, a potent inhibitor of fungal inositol phosphorylceramide synthases, does not significantly affect any of the TbSLS activities, consistent with the phylogenetic distance of these two clades of sphingolipid synthases. These results represent the first application of cell-free synthesis for the rapid preparation and functional annotation of integral membrane proteins and thus illustrate its utility in studying otherwise intractable enzyme systems.
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Affiliation(s)
- Elitza S. Sevova
- From the Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | | | - Kevin J. Schwartz
- From the Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Fong-Fu Hsu
- the Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - John Turk
- the Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Brian G. Fox
- the Department of Biochemistry and
- the Center for Eukaryotic Structural Genomics, College of Agriculture and Life Sciences, University of Wisconsin, Madison, Wisconsin 53706, and
| | - James D. Bangs
- From the Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
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Sadre R, Frentzen M, Saeed M, Hawkes T. Catalytic reactions of the homogentisate prenyl transferase involved in plastoquinone-9 biosynthesis. J Biol Chem 2010; 285:18191-8. [PMID: 20400515 PMCID: PMC2881743 DOI: 10.1074/jbc.m110.117929] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2010] [Revised: 04/15/2010] [Indexed: 11/06/2022] Open
Abstract
Homogentisate solanesyl transferase (HST) catalyzes the prenylation and decarboxylation of homogentisate to form 2-methyl-6-solanesyl-1,4-benzoquinol, the first intermediate in plastoquinone-9 biosynthesis. In vitro, HST from Spinacia oleracea L., Arabidopsis thaliana, and Chlamydomonas reinhardtii were all found to use not only solanesyl diphosphate but also short chain prenyl diphosphates of 10-20 carbon atoms as prenyl donors. Surprisingly, with these donors, prenyl transfer was largely decoupled from decarboxylation, and thus the major products were 6-prenyl-1,4-benzoquinol-2-methylcarboxylates rather than the expected 2-methyl-6-prenyl-1,4-benzoquinols. The 6-prenyl-1,4-benzoquinol-2-methylcarboxylates were not substrates for HST-catalyzed decarboxylation, and the enzyme kinetics associated with forming these products appeared quite distinct from those for 2-methyl-6-prenyl-1,4-benzoquinol formation in respect of catalytic rate, substrate K(m) value, and the pattern of inhibition by haloxydine, a molecule that appeared to act as a dead end mimic of homogentisate. These observations were reconciled into a simple model for the HST mechanism. Here, prenyl diphosphate binds to HST to form at least two alternative complexes that go on to react differently with homogentisate and prenylate it either with or without it first being decarboxylated. It is supposed that solanesyl diphosphate binds tightly and preferentially in the mode that compels prenylation with decarboxylation.
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Affiliation(s)
- Radin Sadre
- Institute for Biology I, Botany, RWTH Aachen University, Worringerweg 1, 52056 Aachen, Germany.
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Abstract
Three purified molecular forms of acetylcholinesterase (EC 3.1.1.7) with sedimentation coefficients of 18 S, 14 S, and 11 S were studied by analytical ultracentrifugation and electron microscopy. The three species have molecular weights of (1.1 +/- 0.1) x 10(6), (7.5 +/- 1.5) x 10(5), and (3.35 +/- 0.25) x 10(5), respectively. Electron micrographs reveal that the 18S and 14S forms are asymmetric, composed of a head, containing a large number of subunits, and an elongated tail. The 11S form of acetylcholinesterase is apparently a tetrameric structure devoid of the tail. Maleylation of 18S and 14S acetylcholinesterases abolishes their tendency to aggregate at low ionic strength.
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