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Giolito ML, Bigliani G, Meinero R, Taubas JV. Palmitoylation of CYSTM (CYSPD) proteins in yeast. J Biol Chem 2024; 300:105609. [PMID: 38159851 PMCID: PMC10840359 DOI: 10.1016/j.jbc.2023.105609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 12/11/2023] [Accepted: 12/14/2023] [Indexed: 01/03/2024] Open
Abstract
A superfamily of proteins called cysteine transmembrane is widely distributed across eukaryotes. These small proteins are characterized by the presence of a conserved motif at the C-terminal region, rich in cysteines, that has been annotated as a transmembrane domain. Orthologs of these proteins have been involved in resistance to pathogens and metal detoxification. The yeast members of the family are YBR016W, YDL012C, YDR034W-B, and YDR210W. Here, we begin the characterization of these proteins at the molecular level and show that Ybr016w, Ydr034w-b, and Ydr210w are palmitoylated proteins. Protein S-acylation or palmitoylation, is a posttranslational modification that consists of the addition of long-chain fatty acids to cysteine residues. We provide evidence that Ybr016w, Ydr210w, and Ydr034w-b are localized to the plasma membrane and exhibit varying degrees of polarity toward the daughter cell, which is dependent on endocytosis and recycling. We suggest the names CPP1, CPP2, and CPP3 (C terminally palmitoylated protein) for YBR016W, YDR210W, and YDR034W-B, respectively. We show that palmitoylation is responsible for the binding of these proteins to the membrane indicating that the cysteine transmembrane on these proteins is not a transmembrane domain. We propose renaming the C-terminal cysteine-rich domain as cysteine-rich palmitoylated domain. Loss of the palmitoyltransferase Erf2 leads to partial degradation of Ybr016w (Cpp1), whereas in the absence of the palmitoyltransferase Akr1, members of this family are completely degraded. For Cpp1, we show that this degradation occurs via the proteasome in an Rsp5-dependent manner, but is not exclusively due to a lack of Cpp1 palmitoylation.
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Affiliation(s)
- María Luz Giolito
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina; Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Gonzalo Bigliani
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina; Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Rocío Meinero
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina; Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Javier Valdez Taubas
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET, Universidad Nacional de Córdoba, Córdoba, Argentina; Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.
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2
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Porcellato E, González-Sánchez JC, Ahlmann-Eltze C, Elsakka MA, Shapira I, Fritsch J, Navarro JA, Anders S, Russell RB, Wieland FT, Metzendorf C. The S-palmitoylome and DHHC-PAT interactome of Drosophila melanogaster S2R+ cells indicate a high degree of conservation to mammalian palmitoylomes. PLoS One 2022; 17:e0261543. [PMID: 35960718 PMCID: PMC9374236 DOI: 10.1371/journal.pone.0261543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 07/28/2022] [Indexed: 11/18/2022] Open
Abstract
Protein S-palmitoylation, the addition of a long-chain fatty acid to target proteins, is among the most frequent reversible protein modifications in Metazoa, affecting subcellular protein localization, trafficking and protein-protein interactions. S-palmitoylated proteins are abundant in the neuronal system and are associated with neuronal diseases and cancer. Despite the importance of this post-translational modification, it has not been thoroughly studied in the model organism Drosophila melanogaster. Here we present the palmitoylome of Drosophila S2R+ cells, comprising 198 proteins, an estimated 3.5% of expressed genes in these cells. Comparison of orthologs between mammals and Drosophila suggests that S-palmitoylated proteins are more conserved between these distant phyla than non-S-palmitoylated proteins. To identify putative client proteins and interaction partners of the DHHC family of protein acyl-transferases (PATs) we established DHHC-BioID, a proximity biotinylation-based method. In S2R+ cells, ectopic expression of the DHHC-PAT dHip14-BioID in combination with Snap24 or an interaction-deficient Snap24-mutant as a negative control, resulted in biotinylation of Snap24 but not the Snap24-mutant. DHHC-BioID in S2R+ cells using 10 different DHHC-PATs as bait identified 520 putative DHHC-PAT interaction partners of which 48 were S-palmitoylated and are therefore putative DHHC-PAT client proteins. Comparison of putative client protein/DHHC-PAT combinations indicates that CG8314, CG5196, CG5880 and Patsas have a preference for transmembrane proteins, while S-palmitoylated proteins with the Hip14-interaction motif are most enriched by DHHC-BioID variants of approximated and dHip14. Finally, we show that BioID is active in larval and adult Drosophila and that dHip14-BioID rescues dHip14 mutant flies, indicating that DHHC-BioID is non-toxic. In summary we provide the first systematic analysis of a Drosophila palmitoylome. We show that DHHC-BioID is sensitive and specific enough to identify DHHC-PAT client proteins and provide DHHC-PAT assignment for ca. 25% of the S2R+ cell palmitoylome, providing a valuable resource. In addition, we establish DHHC-BioID as a useful concept for the identification of tissue-specific DHHC-PAT interactomes in Drosophila.
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Affiliation(s)
- Elena Porcellato
- Heidelberg University Biochemistry Center (BZH), Heidelberg University, Heidelberg, Germany
| | - Juan Carlos González-Sánchez
- Heidelberg University Biochemistry Center (BZH), Heidelberg University, Heidelberg, Germany
- BioQuant, Heidelberg University, Heidelberg, Germany
| | | | - Mahmoud Ali Elsakka
- Heidelberg University Biochemistry Center (BZH), Heidelberg University, Heidelberg, Germany
| | - Itamar Shapira
- Heidelberg University Biochemistry Center (BZH), Heidelberg University, Heidelberg, Germany
| | - Jürgen Fritsch
- Institute of Immunology, Universitätsklinikum Schleswig-Holstein, Kiel, Germany
| | | | - Simon Anders
- Centre for Molecular Biology of the University of Heidelberg (ZMBH), Heidelberg, Germany
| | - Robert B. Russell
- Heidelberg University Biochemistry Center (BZH), Heidelberg University, Heidelberg, Germany
- BioQuant, Heidelberg University, Heidelberg, Germany
| | - Felix T. Wieland
- Heidelberg University Biochemistry Center (BZH), Heidelberg University, Heidelberg, Germany
| | - Christoph Metzendorf
- Heidelberg University Biochemistry Center (BZH), Heidelberg University, Heidelberg, Germany
- * E-mail:
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3
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Coronel Arrechea C, Giolito ML, García IA, Soria G, Valdez Taubas J. A novel yeast-based high-throughput method for the identification of protein palmitoylation inhibitors. Open Biol 2021; 11:200415. [PMID: 34343464 PMCID: PMC8331233 DOI: 10.1098/rsob.200415] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Protein S-acylation or palmitoylation is a widespread post-translational modification that consists of the addition of a lipid molecule to cysteine residues of proteins through a thioester bond. Palmitoylation and palmitoyltransferases (PATs) have been linked to several types of cancers, diseases of the central nervous system and many infectious diseases where pathogens use the host cell machinery to palmitoylate their effectors. Despite the central importance of palmitoylation in cell physiology and disease, progress in the field has been hampered by the lack of potent-specific inhibitors of palmitoylation in general, and of individual PATs in particular. Herein, we present a yeast-based method for the high-throughput identification of small molecules that inhibit protein palmitoylation. The system is based on a reporter gene that responds to the acylation status of a palmitoylation substrate fused to a transcription factor. The method can be applied to heterologous PATs such as human DHHC20, mouse DHHC21 and also a PAT from the parasite Giardia lamblia. As a proof-of-principle, we screened for molecules that inhibit the palmitoylation of Yck2, a substrate of the yeast PAT Akr1. We tested 3200 compounds and were able to identify a candidate molecule, supporting the validity of our method.
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Affiliation(s)
- Consuelo Coronel Arrechea
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC) CONICET, Córdoba, Argentina.,Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Córdoba, Argentina
| | - María Luz Giolito
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC) CONICET, Córdoba, Argentina.,Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Córdoba, Argentina
| | - Iris Alejandra García
- Centro de Investigaciones en Bioquímica Clínica e Inmunología, CIBICI-CONICET, Córdoba, Argentina
| | - Gastón Soria
- Departamento de Bioquímica Clínica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Córdoba, Argentina.,Centro de Investigaciones en Bioquímica Clínica e Inmunología, CIBICI-CONICET, Córdoba, Argentina
| | - Javier Valdez Taubas
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC) CONICET, Córdoba, Argentina.,Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas, Córdoba, Argentina
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4
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Stix R, Lee CJ, Faraldo-Gómez JD, Banerjee A. Structure and Mechanism of DHHC Protein Acyltransferases. J Mol Biol 2020; 432:4983-4998. [PMID: 32522557 DOI: 10.1016/j.jmb.2020.05.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 05/26/2020] [Accepted: 05/28/2020] [Indexed: 01/01/2023]
Abstract
S-acylation, whereby a fatty acid chain is covalently linked to a cysteine residue by a thioester linkage, is the most prevalent kind of lipid modification of proteins. Thousands of proteins are targets of this post-translational modification, which is catalyzed by a family of eukaryotic integral membrane enzymes known as DHHC protein acyltransferases (DHHC-PATs). Our knowledge of the repertoire of S-acylated proteins has been rapidly expanding owing to development of the chemoproteomic techniques. There has also been an increasing number of reports in the literature documenting the importance of S-acylation in human physiology and disease. Recently, the first atomic structures of two different DHHC-PATs were determined using X-ray crystallography. This review will focus on the insights gained into the molecular mechanism of DHHC-PATs from these structures and highlight representative data from the biochemical literature that they help explain.
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Affiliation(s)
- Robyn Stix
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chul-Jin Lee
- Unit on Structural and Chemical Biology of Membrane Proteins, Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - José D Faraldo-Gómez
- Theoretical Molecular Biophysics Laboratory, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anirban Banerjee
- Unit on Structural and Chemical Biology of Membrane Proteins, Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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5
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The molecular mechanism of DHHC protein acyltransferases. Biochem Soc Trans 2018; 47:157-167. [PMID: 30559274 DOI: 10.1042/bst20180429] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/01/2018] [Accepted: 11/06/2018] [Indexed: 01/04/2023]
Abstract
Protein S-acylation is a reversible lipidic posttranslational modification where a fatty acid chain is covalently linked to cysteine residues by a thioester linkage. A family of integral membrane enzymes known as DHHC protein acyltransferases (DHHC-PATs) catalyze this reaction. With the rapid development of the techniques used for identifying lipidated proteins, the repertoire of S-acylated proteins continues to increase. This, in turn, highlights the important roles that S-acylation plays in human physiology and disease. Recently, the first molecular structures of DHHC-PATs were determined using X-ray crystallography. This review will comment on the insights gained on the molecular mechanism of S-acylation from these structures in combination with a wealth of biochemical data generated by researchers in the field.
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6
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Zaballa ME, van der Goot FG. The molecular era of protein S-acylation: spotlight on structure, mechanisms, and dynamics. Crit Rev Biochem Mol Biol 2018; 53:420-451. [DOI: 10.1080/10409238.2018.1488804] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- María-Eugenia Zaballa
- Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - F. Gisou van der Goot
- Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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Rodenburg RNP, Snijder J, van de Waterbeemd M, Schouten A, Granneman J, Heck AJR, Gros P. Stochastic palmitoylation of accessible cysteines in membrane proteins revealed by native mass spectrometry. Nat Commun 2017; 8:1280. [PMID: 29097667 PMCID: PMC5668376 DOI: 10.1038/s41467-017-01461-z] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 09/19/2017] [Indexed: 01/09/2023] Open
Abstract
Palmitoylation affects membrane partitioning, trafficking and activities of membrane proteins. However, how specificity of palmitoylation and multiple palmitoylations in membrane proteins are determined is not well understood. Here, we profile palmitoylation states of three human claudins, human CD20 and cysteine-engineered prokaryotic KcsA and bacteriorhodopsin by native mass spectrometry. Cysteine scanning of claudin-3, KcsA, and bacteriorhodopsin shows that palmitoylation is independent of a sequence motif. Palmitoylations are observed for cysteines exposed on the protein surface and situated up to 8 Å into the inner leaflet of the membrane. Palmitoylation on multiple sites in claudin-3 and CD20 occurs stochastically, giving rise to a distribution of palmitoylated membrane-protein isoforms. Non-native sites in claudin-3 indicate that membrane-protein function imposed evolutionary restraints on native palmitoylation sites. These results suggest a generic, stochastic membrane-protein palmitoylation process that is determined by the accessibility of palmitoyl-acyl transferases to cysteines on membrane-embedded proteins, and not by a preferred substrate-sequence motif.
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Affiliation(s)
- Remco N P Rodenburg
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Dept. of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584CH, Utrecht, The Netherlands
| | - Joost Snijder
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Padualaan 8, 3584CH, Utrecht, The Netherlands
| | - Michiel van de Waterbeemd
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Padualaan 8, 3584CH, Utrecht, The Netherlands
| | - Arie Schouten
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Dept. of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584CH, Utrecht, The Netherlands
| | - Joke Granneman
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Dept. of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584CH, Utrecht, The Netherlands
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Padualaan 8, 3584CH, Utrecht, The Netherlands.
| | - Piet Gros
- Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Dept. of Chemistry, Faculty of Science, Utrecht University, Padualaan 8, 3584CH, Utrecht, The Netherlands.
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8
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Daniotti JL, Pedro MP, Valdez Taubas J. The role of S-acylation in protein trafficking. Traffic 2017; 18:699-710. [DOI: 10.1111/tra.12510] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 08/16/2017] [Accepted: 08/20/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Jose L. Daniotti
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET; Universidad Nacional de Córdoba; Córdoba Argentina
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas; Universidad Nacional de Córdoba; Córdoba Argentina
| | - Maria P. Pedro
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET; Universidad Nacional de Córdoba; Córdoba Argentina
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas; Universidad Nacional de Córdoba; Córdoba Argentina
| | - Javier Valdez Taubas
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET; Universidad Nacional de Córdoba; Córdoba Argentina
- Departamento de Química Biológica Ranwel Caputto, Facultad de Ciencias Químicas; Universidad Nacional de Córdoba; Córdoba Argentina
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9
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Ganglioside glycosyltransferases are S-acylated at conserved cysteine residues involved in homodimerisation. Biochem J 2017; 474:2803-2816. [DOI: 10.1042/bcj20170124] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 06/30/2017] [Accepted: 07/11/2017] [Indexed: 01/06/2023]
Abstract
Ganglioside glycosyltransferases (GGTs) are type II membrane proteins bearing a short N-terminal cytoplasmic tail, a transmembrane domain (TMD), and a lumenal catalytic domain. The expression and activity of these enzymes largely determine the quality of the glycolipids that decorate mammalian cell membranes. Many glycosyltransferases (GTs) are themselves glycosylated, and this is important for their proper localisation, but few if any other post-translational modifications of these proteins have been reported. Here, we show that the GGTs, ST3Gal-V, ST8Sia-I, and β4GalNAcT-I are S-acylated at conserved cysteine residues located close to the cytoplasmic border of their TMDs. ST3Gal-II, a GT that sialylates glycolipids and glycoproteins, is also S-acylated at a conserved cysteine located in the N-terminal cytoplasmic tail. Many other GTs also possess cysteine residues in their cytoplasmic regions, suggesting that this modification occurs also on these GTs. S-acylation, commonly known as palmitoylation, is catalysed by a family of palmitoyltransferases (PATs) that are mostly localised at the Golgi complex but also at the endoplasmic reticulum (ER) and the plasma membrane. Using GT ER retention mutants, we found that S-acylation of β4GalNAcT-I and ST3Gal-II takes place at different compartments, suggesting that these enzymes are not substrates of the same PAT. Finally, we found that cysteines that are the target of S-acylation on β4GalNAcT-I and ST3Gal-II are involved in the formation of homodimers through disulphide bonds. We observed an increase in ST3Gal-II dimers in the presence of the PAT inhibitor 2-bromopalmitate, suggesting that GT homodimerisation may be regulating S-acylation
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10
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Li Y, Qi B. Progress toward Understanding Protein S-acylation: Prospective in Plants. FRONTIERS IN PLANT SCIENCE 2017; 8:346. [PMID: 28392791 PMCID: PMC5364179 DOI: 10.3389/fpls.2017.00346] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 02/28/2017] [Indexed: 05/02/2023]
Abstract
S-acylation, also known as S-palmitoylation or palmitoylation, is a reversible post-translational lipid modification in which long chain fatty acid, usually the 16-carbon palmitate, covalently attaches to a cysteine residue(s) throughout the protein via a thioester bond. It is involved in an array of important biological processes during growth and development, reproduction and stress responses in plant. S-acylation is a ubiquitous mechanism in eukaryotes catalyzed by a family of enzymes called Protein S-Acyl Transferases (PATs). Since the discovery of the first PAT in yeast in 2002 research in S-acylation has accelerated in the mammalian system and followed by in plant. However, it is still a difficult field to study due to the large number of PATs and even larger number of putative S-acylated substrate proteins they modify in each genome. This is coupled with drawbacks in the techniques used to study S-acylation, leading to the slower progress in this field compared to protein phosphorylation, for example. In this review we will summarize the discoveries made so far based on knowledge learnt from the characterization of protein S-acyltransferases and the S-acylated proteins, the interaction mechanisms between PAT and its specific substrate protein(s) in yeast and mammals. Research in protein S-acylation and PATs in plants will also be covered although this area is currently less well studied in yeast and mammalian systems.
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Li Y, Scott R, Doughty J, Grant M, Qi B. Protein S-Acyltransferase 14: A Specific Role for Palmitoylation in Leaf Senescence in Arabidopsis. PLANT PHYSIOLOGY 2016; 170:415-28. [PMID: 26537563 PMCID: PMC4704564 DOI: 10.1104/pp.15.00448] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 11/03/2015] [Indexed: 05/18/2023]
Abstract
The Asp-His-His-Cys-Cys-rich domain-containing Protein S-Acyl Transferases (PATs) are multipass transmembrane proteins that catalyze S-acylation (commonly known as S-palmitoylation), the reversible posttranslational lipid modification of proteins. Palmitoylation enhances the hydrophobicity of proteins, contributes to their membrane association, and plays roles in protein trafficking and signaling. In Arabidopsis (Arabidopsis thaliana), there are at least 24 PATs; previous studies on two PATs established important roles in growth, development, and stress responses. In this study, we identified a, to our knowledge, novel PAT, AtPAT14, in Arabidopsis. Complementation studies in yeast (Saccharomyces cerevisiae) and Arabidopsis demonstrate that AtPAT14 possesses PAT enzyme activity. Disruption of AtPAT14 by T-DNA insertion resulted in an accelerated senescence phenotype. This coincided with increased transcript levels of some senescence-specific and pathogen-resistant marker genes. We show that early senescence of pat14 does not involve the signaling molecules jasmonic acid and abscisic acid, or autophagy, but associates with salicylic acid homeostasis and signaling. This strongly suggests that AtPAT14 plays a pivotal role in regulating senescence via salicylic acid pathways. Senescence is a complex process required for normal plant growth and development and requires the coordination of many genes and signaling pathways. However, precocious senescence results in loss of biomass and seed production. The negative regulation of leaf senescence by AtPAT14 in Arabidopsis highlights, to our knowledge for the first time, a specific role for palmitoylation in leaf senescence.
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Affiliation(s)
- Yaxiao Li
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom (Y.L., R.S., J.D., B.Q.); andCollege of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom (M.G.)
| | - Rod Scott
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom (Y.L., R.S., J.D., B.Q.); andCollege of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom (M.G.)
| | - James Doughty
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom (Y.L., R.S., J.D., B.Q.); andCollege of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom (M.G.)
| | - Murray Grant
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom (Y.L., R.S., J.D., B.Q.); andCollege of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom (M.G.)
| | - Baoxiu Qi
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom (Y.L., R.S., J.D., B.Q.); andCollege of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom (M.G.)
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Srivastava V, Weber JR, Malm E, Fouke BW, Bulone V. Proteomic Analysis of a Poplar Cell Suspension Culture Suggests a Major Role of Protein S-Acylation in Diverse Cellular Processes. FRONTIERS IN PLANT SCIENCE 2016; 7:477. [PMID: 27148305 PMCID: PMC4828459 DOI: 10.3389/fpls.2016.00477] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 03/24/2016] [Indexed: 05/03/2023]
Abstract
S-acylation is a reversible post-translational modification of proteins known to be involved in membrane targeting, subcellular trafficking, and the determination of a great variety of functional properties of proteins. The aim of this work was to identify S-acylated proteins in poplar. The use of an acyl-biotin exchange method and mass spectrometry allowed the identification of around 450 S-acylated proteins, which were subdivided into three major groups of proteins involved in transport, signal transduction, and response to stress, respectively. The largest group of S-acylated proteins was the protein kinase superfamily. Soluble N-ethylmaleimide-sensitive factor-activating protein receptors, band 7 family proteins and tetraspanins, all primarily related to intracellular trafficking, were also identified. In addition, cell wall related proteins, including cellulose synthases and other glucan synthases, were found to be S-acylated. Twenty four of the identified S-acylated proteins were also enriched in detergent-resistant membrane microdomains, suggesting S-acylation plays a key role in the localization of proteins to specialized plasma membrane subdomains. This dataset promises to enhance our current understanding of the various functions of S-acylated proteins in plants.
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Affiliation(s)
- Vaibhav Srivastava
- Division of Glycoscience, School of Biotechnology, Royal Institute of Technology, AlbaNova University CentreStockholm, Sweden
- *Correspondence: Vincent Bulone, ; Vaibhav Srivastava,
| | - Joseph R. Weber
- Roy J. Carver Biotechnology Centre, Institute for Genomic Biology, University of Illinois Urbana–ChampaignUrbana, IL, USA
| | - Erik Malm
- Division of Glycoscience, School of Biotechnology, Royal Institute of Technology, AlbaNova University CentreStockholm, Sweden
| | - Bruce W. Fouke
- Roy J. Carver Biotechnology Centre, Institute for Genomic Biology, University of Illinois Urbana–ChampaignUrbana, IL, USA
| | - Vincent Bulone
- Division of Glycoscience, School of Biotechnology, Royal Institute of Technology, AlbaNova University CentreStockholm, Sweden
- ARC Centre of Excellence in Plant Cell Walls and School of Agriculture, Food and Wine, The University of Adelaide, Waite CampusUrrbrae, SA, Australia
- *Correspondence: Vincent Bulone, ; Vaibhav Srivastava,
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13
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González Montoro A, Chumpen Ramirez S, Valdez Taubas J. The canonical DHHC motif is not absolutely required for the activity of the yeast S-acyltransferases Swf1 and Pfa4. J Biol Chem 2015. [PMID: 26224664 DOI: 10.1074/jbc.m115.651356] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein S-acyltransferases, also known as palmitoyltransferases (PATs), are characterized by the presence of a 50-amino acid domain called the DHHC domain. Within this domain, these four amino acids constitute a highly conserved motif. It has been proposed that the palmitoylation reaction occurs through a palmitoyl-PAT covalent intermediate that involves the conserved cysteine in the DHHC motif. Mutation of this cysteine results in lack of function for several PATs, and DHHA or DHHS mutants are used regularly as catalytically inactive controls. In a genetic screen to isolate loss-of-function mutations in the yeast PAT Swf1, we isolated an allele encoding a Swf1 DHHR mutant. Overexpression of this mutant is able to partially complement a swf1Δ strain and to acylate the Swf1 substrates Tlg1, Syn8, and Snc1. Overexpression of the palmitoyltransferase Pfa4 DHHA or DHHR mutants also results in palmitoylation of its substrate Chs3. We also investigated the role of the first histidine of the DHHC motif. A Swf1 DQHC mutant is also partially active but a DQHR is not. Finally, we show that Swf1 substrates are differentially modified by both DHHR and DQHC Swf1 mutants. We propose that, in the absence of the canonical mechanism, alternative suboptimal mechanisms take place that are more dependent on the reactivity of the acceptor protein. These results also imply that caution must be exercised when proposing non-canonical roles for PATs on the basis of considering DHHC mutants as catalytically inactive and, more generally, contribute to an understanding of the mechanism of protein palmitoylation.
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Affiliation(s)
- Ayelén González Montoro
- From the Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina
| | - Sabrina Chumpen Ramirez
- From the Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina
| | - Javier Valdez Taubas
- From the Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC), CONICET and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, Córdoba, Argentina
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14
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Abstract
Protein S-acylation, the only fully reversible posttranslational lipid modification of proteins, is emerging as a ubiquitous mechanism to control the properties and function of a diverse array of proteins and consequently physiological processes. S-acylation results from the enzymatic addition of long-chain lipids, most typically palmitate, onto intracellular cysteine residues of soluble and transmembrane proteins via a labile thioester linkage. Addition of lipid results in increases in protein hydrophobicity that can impact on protein structure, assembly, maturation, trafficking, and function. The recent explosion in global S-acylation (palmitoyl) proteomic profiling as a result of improved biochemical tools to assay S-acylation, in conjunction with the recent identification of enzymes that control protein S-acylation and de-acylation, has opened a new vista into the physiological function of S-acylation. This review introduces key features of S-acylation and tools to interrogate this process, and highlights the eclectic array of proteins regulated including membrane receptors, ion channels and transporters, enzymes and kinases, signaling adapters and chaperones, cell adhesion, and structural proteins. We highlight recent findings correlating disruption of S-acylation to pathophysiology and disease and discuss some of the major challenges and opportunities in this rapidly expanding field.
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Affiliation(s)
- Luke H Chamberlain
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Strathclyde University, Glasgow, United Kingdom; and Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Michael J Shipston
- Strathclyde Institute of Pharmacy and Biomedical Sciences, Strathclyde University, Glasgow, United Kingdom; and Centre for Integrative Physiology, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
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15
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A Single Protein S-acyl Transferase Acts through Diverse Substrates to Determine Cryptococcal Morphology, Stress Tolerance, and Pathogenic Outcome. PLoS Pathog 2015; 11:e1004908. [PMID: 25970403 PMCID: PMC4430228 DOI: 10.1371/journal.ppat.1004908] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 04/23/2015] [Indexed: 12/17/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic yeast that kills over 625,000 people yearly through lethal meningitis. Host phagocytes serve as the first line of defense against this pathogen, but fungal engulfment and subsequent intracellular proliferation also correlate with poor patient outcome. Defining the interactions of this facultative intracellular pathogen with host phagocytes is key to understanding the latter's opposing roles in infection and how they contribute to fungal latency, dissemination, and virulence. We used high-content imaging and a human monocytic cell line to screen 1,201 fungal mutants for strains with altered host interactions and identified multiple genes that influence fungal adherence and phagocytosis. One of these genes was PFA4, which encodes a protein S-acyl transferase (PAT), one of a family of DHHC domain-containing proteins that catalyzes lipid modification of proteins. Deletion of PFA4 caused dramatic defects in cryptococcal morphology, stress tolerance, and virulence. Bioorthogonal palmitoylome-profiling identified Pfa4-specific protein substrates involved in cell wall synthesis, signal transduction, and membrane trafficking responsible for these phenotypic alterations. We demonstrate that a single PAT is responsible for the modification of a subset of proteins that are critical in cryptococcal pathogenesis. Since several of these palmitoylated substrates are conserved in other pathogenic fungi, protein palmitoylation represents a potential avenue for new antifungal therapeutics.
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16
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Blaskovic S, Adibekian A, Blanc M, van der Goot GF. Mechanistic effects of protein palmitoylation and the cellular consequences thereof. Chem Phys Lipids 2014; 180:44-52. [PMID: 24534427 DOI: 10.1016/j.chemphyslip.2014.02.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/31/2014] [Accepted: 02/03/2014] [Indexed: 12/21/2022]
Abstract
S-palmitoylation involves the attachment of a 16-carbon long fatty acid chain to the cysteine residues of proteins. The process is enzymatic and dynamic with DHHC enzymes mediating palmitoylation and acyl-protein thioesterases reverting the reaction. Proteins that undergo this modification span almost all cellular functions. While the increase in hydrophobicity generated by palmitoylation has the obvious consequence of triggering membrane association, the effects on transmembrane proteins are less intuitive and span a vast range. We review here the current knowledge on palmitoylating and depalmitoylating enzymes, the methods that allow the study of this lipid modification and which drugs can affect it, and finally we focus on four cellular processes for which recent studies reveal an involvement of palmitoylation: endocytosis, reproduction and cell growth, fat and sugar homeostasis and signal transduction at the synapse.
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Affiliation(s)
- Sanja Blaskovic
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 19, CH-1015 Lausanne, Switzerland
| | - Alexander Adibekian
- Department of Organic Chemistry, University of Geneva, 1211 Geneva, Switzerland
| | - Mathieu Blanc
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 19, CH-1015 Lausanne, Switzerland
| | - Gisou F van der Goot
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 19, CH-1015 Lausanne, Switzerland.
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17
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Zinc co-ordination by the DHHC cysteine-rich domain of the palmitoyltransferase Swf1. Biochem J 2013; 454:427-35. [PMID: 23790227 DOI: 10.1042/bj20121693] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
S-acylation, commonly known as palmitoylation, is a widespread post-translational modification of proteins that consists of the thioesterification of one or more cysteine residues with fatty acids. This modification is catalysed by a family of PATs (palmitoyltransferases), characterized by the presence of a 50-residue long DHHC-CRD (Asp-His-His-Cys cysteine-rich domain). To gain knowledge on the structure-function relationships of these proteins, we carried out a random-mutagenesis assay designed to uncover essential amino acids in Swf1, the yeast PAT responsible for the palmitoylation of SNARE (soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptor) proteins. We identified 21 novel loss-of-function mutations, which are mostly localized within the DHHC-CRD. Modelling of the tertiary structure of the Swf1 DHHC domain suggests that it could fold as a zinc-finger domain, co-ordinating two zinc atoms in a CCHC arrangement. All residues predicted to be involved in the co-ordination of zinc were found to be essential for Swf1 function in the screen. Moreover, these mutations result in unstable proteins, in agreement with a structural role for these zinc fingers. The conservation of amino acids predicted to form each zinc-binding pocket suggests a shared function, as the selective pressure to maintain them is lost upon mutation of one of them. A Swf1 orthologue that lacks one of the zinc-binding pockets is able to complement a yeast swf1∆ strain, possibly because a similar fold can be stabilized by hydrogen bonds instead of zinc co-ordination. Finally, we show directly that recombinant Swf1 DHHC-CRD is able to bind zinc. Sequence analyses of DHHC domains allowed us to present models of the zinc-binding properties for all PATs.
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18
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Qi B, Doughty J, Hooley R. A Golgi and tonoplast localized S-acyl transferase is involved in cell expansion, cell division, vascular patterning and fertility in Arabidopsis. THE NEW PHYTOLOGIST 2013; 200:444-456. [PMID: 23795888 PMCID: PMC3817529 DOI: 10.1111/nph.12385] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 05/23/2013] [Indexed: 05/04/2023]
Abstract
S-acylation of eukaryotic proteins is the reversible attachment of palmitic or stearic acid to cysteine residues, catalysed by protein S-acyl transferases that share an Asp-His-His-Cys (DHHC) motif. Previous evidence suggests that in Arabidopsis S-acylation is involved in the control of cell size, polarity and the growth of pollen tubes and root hairs. Using a combination of yeast genetics, biochemistry, cell biology and loss of function genetics the roles of a member of the protein S-acyl transferase PAT family, AtPAT10 (At3g51390), have been explored. In keeping with its role as a PAT, AtPAT10 auto-S-acylates, and partially complements the yeast akr1 PAT mutant, and this requires Cys(192) of the DHHC motif. In Arabidopsis AtPAT10 is localized in the Golgi stack, trans-Golgi network/early endosome and tonoplast. Loss-of-function mutants have a pleiotropic phenotype involving cell expansion and division, vascular patterning, and fertility that is rescued by wild-type AtPAT10 but not by catalytically inactive AtPAT10C(192) A. This supports the hypothesis that AtPAT10 is functionally independent of the other Arabidopsis PATs. Our findings demonstrate a growing importance of protein S-acylation in plants, and reveal a Golgi and tonoplast located S-acylation mechanism that affects a range of events during growth and development in Arabidopsis.
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Affiliation(s)
- Baoxiu Qi
- Department of Biology and Biochemistry, University of BathClaverton Down, Bath, BA2 7AY, UK
- State Key Laboratory of Crop Biology, Shandong Agricultural UniversityShandong, 271018, China
| | - James Doughty
- Department of Biology and Biochemistry, University of BathClaverton Down, Bath, BA2 7AY, UK
| | - Richard Hooley
- Department of Biology and Biochemistry, University of BathClaverton Down, Bath, BA2 7AY, UK
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19
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Blaskovic S, Blanc M, van der Goot FG. What does S-palmitoylation do to membrane proteins? FEBS J 2013; 280:2766-74. [PMID: 23551889 DOI: 10.1111/febs.12263] [Citation(s) in RCA: 182] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Revised: 03/20/2013] [Accepted: 03/25/2013] [Indexed: 12/19/2022]
Abstract
S-palmitoylation is post-translational modification, which consists in the addition of a C16 acyl chain to cytosolic cysteines and which is unique amongst lipid modifications in that it is reversible. It can thus, like phosphorylation or ubiquitination, act as a switch. While palmitoylation of soluble proteins allows them to interact with membranes, the consequences of palmitoylation for transmembrane proteins are more enigmatic. We briefly review the current knowledge regarding the enzymes responsible for palmitate addition and removal. We then describe various observed consequences of membrane protein palmitoylation. We propose that the direct effects of palmitoylation on transmembrane proteins, however, might be limited to four non-mutually exclusive mechanistic consequences: alterations in the conformation of transmembrane domains, association with specific membrane domains, controlled interactions with other proteins and controlled interplay with other post-translational modifications.
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Affiliation(s)
- Sanja Blaskovic
- Global Health Institute, Ecole Polytechnique Fédérale de Lausanne, Switzerland
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20
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Orlean P. Architecture and biosynthesis of the Saccharomyces cerevisiae cell wall. Genetics 2012; 192:775-818. [PMID: 23135325 PMCID: PMC3522159 DOI: 10.1534/genetics.112.144485] [Citation(s) in RCA: 296] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 08/06/2012] [Indexed: 01/02/2023] Open
Abstract
The wall gives a Saccharomyces cerevisiae cell its osmotic integrity; defines cell shape during budding growth, mating, sporulation, and pseudohypha formation; and presents adhesive glycoproteins to other yeast cells. The wall consists of β1,3- and β1,6-glucans, a small amount of chitin, and many different proteins that may bear N- and O-linked glycans and a glycolipid anchor. These components become cross-linked in various ways to form higher-order complexes. Wall composition and degree of cross-linking vary during growth and development and change in response to cell wall stress. This article reviews wall biogenesis in vegetative cells, covering the structure of wall components and how they are cross-linked; the biosynthesis of N- and O-linked glycans, glycosylphosphatidylinositol membrane anchors, β1,3- and β1,6-linked glucans, and chitin; the reactions that cross-link wall components; and the possible functions of enzymatic and nonenzymatic cell wall proteins.
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Affiliation(s)
- Peter Orlean
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.
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21
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Plasma membrane localization is required for RasA-mediated polarized morphogenesis and virulence of Aspergillus fumigatus. EUKARYOTIC CELL 2012; 11:966-77. [PMID: 22562470 DOI: 10.1128/ec.00091-12] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Ras is a highly conserved GTPase protein that is essential for proper polarized morphogenesis of filamentous fungi. Localization of Ras proteins to the plasma membrane and endomembranes through posttranslational addition of farnesyl and palmitoyl residues is an important mechanism through which cells provide specificity to Ras signal output. Although the Aspergillus fumigatus RasA protein is known to be a major regulator of growth and development, the membrane distribution of RasA during polarized morphogenesis and the role of properly localized Ras signaling in virulence of a pathogenic mold remain unknown. Here we demonstrate that Aspergillus fumigatus RasA localizes primarily to the plasma membrane of actively growing hyphae. We show that treatment with the palmitoylation inhibitor 2-bromopalmitate disrupts normal RasA plasma membrane association and decreases hyphal growth. Targeted mutations of the highly conserved RasA palmitoylation motif also mislocalized RasA from the plasma membrane and led to severe hyphal abnormalities, cell wall structural changes, and reduced virulence in murine invasive aspergillosis. Finally, we provide evidence that proper RasA localization is independent of the Ras palmitoyltransferase homolog, encoded by erfB, but requires the palmitoyltransferase complex subunit, encoded by erfD. Our results demonstrate that plasma membrane-associated RasA is critical for polarized morphogenesis, cell wall stability, and virulence in A. fumigatus.
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22
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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: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [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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