1
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Kefauver JM, Hakala M, Zou L, Alba J, Espadas J, Tettamanti MG, Gajić J, Gabus C, Campomanes P, Estrozi LF, Sen NE, Vanni S, Roux A, Desfosses A, Loewith R. Cryo-EM architecture of a near-native stretch-sensitive membrane microdomain. Nature 2024; 632:664-671. [PMID: 39048819 PMCID: PMC11324527 DOI: 10.1038/s41586-024-07720-6] [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: 08/25/2023] [Accepted: 06/14/2024] [Indexed: 07/27/2024]
Abstract
Biological membranes are partitioned into functional zones termed membrane microdomains, which contain specific lipids and proteins1-3. The composition and organization of membrane microdomains remain controversial because few techniques are available that allow the visualization of lipids in situ without disrupting their native behaviour3,4. The yeast eisosome, composed of the BAR-domain proteins Pil1 and Lsp1 (hereafter, Pil1/Lsp1), scaffolds a membrane compartment that senses and responds to mechanical stress by flattening and releasing sequestered factors5-9. Here we isolated near-native eisosomes as helical tubules made up of a lattice of Pil1/Lsp1 bound to plasma membrane lipids, and solved their structures by helical reconstruction. Our structures reveal a striking organization of membrane lipids, and, using in vitro reconstitutions and molecular dynamics simulations, we confirmed the positioning of individual PI(4,5)P2, phosphatidylserine and sterol molecules sequestered beneath the Pil1/Lsp1 coat. Three-dimensional variability analysis of the native-source eisosomes revealed a dynamic stretching of the Pil1/Lsp1 lattice that affects the sequestration of these lipids. Collectively, our results support a mechanism in which stretching of the Pil1/Lsp1 lattice liberates lipids that would otherwise be anchored by the Pil1/Lsp1 coat, and thus provide mechanistic insight into how eisosome BAR-domain proteins create a mechanosensitive membrane microdomain.
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Affiliation(s)
- Jennifer M Kefauver
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
- Nanomaterials and Nanotechnology Research Center (CINN), Spanish National Research Council (CSIC), El Entrego, Spain
| | - Markku Hakala
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Luoming Zou
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Josephine Alba
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Javier Espadas
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Maria G Tettamanti
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Jelena Gajić
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland
| | - Caroline Gabus
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Pablo Campomanes
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Leandro F Estrozi
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Nesli E Sen
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland
| | - Stefano Vanni
- Department of Biology, University of Fribourg, Fribourg, Switzerland
- Swiss National Center for Competence in Research (NCCR) Bio-inspired Materials, University of Fribourg, Fribourg, Switzerland
| | - Aurélien Roux
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Ambroise Desfosses
- Institut de Biologie Structurale, Université Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France
| | - Robbie Loewith
- Department of Molecular and Cellular Biology, University of Geneva, Geneva, Switzerland.
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2
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Nomura W, Inoue Y. Activation of the cell wall integrity pathway negatively regulates TORC2-Ypk1/2 signaling through blocking eisosome disassembly in Saccharomyces cerevisiae. Commun Biol 2024; 7:722. [PMID: 38862688 PMCID: PMC11166964 DOI: 10.1038/s42003-024-06411-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 06/03/2024] [Indexed: 06/13/2024] Open
Abstract
The target of rapamycin complex 2 (TORC2) signaling is associated with plasma membrane (PM) integrity. In Saccharomyces cerevisiae, TORC2-Ypk1/2 signaling controls sphingolipid biosynthesis, and Ypk1/2 phosphorylation by TORC2 under PM stress conditions is increased in a Slm1/2-dependent manner, under which Slm1 is known to be released from an eisosome, a furrow-like invagination PM structure. However, it remains unsolved how the activation machinery of TORC2-Ypk1/2 signaling is regulated. Here we show that edelfosine, a synthetic lysophospholipid analog, inhibits the activation of TORC2-Ypk1/2 signaling, and the cell wall integrity (CWI) pathway is involved in this inhibitory effect. The activation of CWI pathway blocked the eisosome disassembly promoted by PM stress and the release of Slm1 from eisosomes. Constitutive activation of TORC2-Ypk1/2 signaling exhibited increased sensitivity to cell wall stress. We propose that the CWI pathway negatively regulates the TORC2-Ypk1/2 signaling, which is involved in the regulatory mechanism to ensure the proper stress response to cell wall damage.
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Affiliation(s)
- Wataru Nomura
- Laboratory of Molecular Microbiology, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, 611-0011, Japan.
- Research Unit for Physiological Chemistry, the Center for the Promotion of Interdisciplinary Education and Research, Kyoto University, Kyoto, 606-8501, Japan.
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Shinshu University, Nagano, 399-4598, Japan.
| | - Yoshiharu Inoue
- Laboratory of Molecular Microbiology, Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, 611-0011, Japan.
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3
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Haase D, Rasch C, Keller U, Tsytsyura Y, Glyvuk N, Elting A, Wittmar J, Janning A, Kahms M, Wedlich N, Schuberth C, Heuer A, Klingauf J, Wedlich-Söldner R. Tetraspanner-based nanodomains modulate BAR domain-induced membrane curvature. EMBO Rep 2023; 24:e57232. [PMID: 37902009 DOI: 10.15252/embr.202357232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 10/02/2023] [Accepted: 10/11/2023] [Indexed: 10/31/2023] Open
Abstract
The topography of biological membranes is critical for formation of protein and lipid microdomains. One prominent example in the yeast plasma membrane (PM) are BAR domain-induced PM furrows. Here we report a novel function for the Sur7 family of tetraspanner proteins in the regulation of local PM topography. Combining TIRF imaging, STED nanoscopy, freeze-fracture EM and membrane simulations we find that Sur7 tetraspanners form multimeric strands at the edges of PM furrows, where they modulate forces exerted by BAR domain proteins at the furrow base. Loss of Sur7 tetraspanners or Sur7 displacement due to altered PIP2 homeostasis leads to increased PM invagination and a distinct form of membrane tubulation. Physiological defects associated with PM tubulation are rescued by synthetic anchoring of Sur7 to furrows. Our findings suggest a key role for tetraspanner proteins in sculpting local membrane domains. The maintenance of stable PM furrows depends on a balance between negative curvature at the base which is generated by BAR domains and positive curvature at the furrows' edges which is stabilized by strands of Sur7 tetraspanners.
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Affiliation(s)
- Daniel Haase
- Institute of Cell Dynamics and Imaging, and Cells-in-Motion Interfaculty Center (CiMIC), University of Münster, Münster, Germany
| | - Christiane Rasch
- Institute for Medical Physics and Biophysics, and Cells-in-Motion Interfaculty Center (CiMIC), Münster, Germany
- Center for Soft Nanoscience, Münster, Germany
| | - Ulrike Keller
- Institute for Medical Physics and Biophysics, and Cells-in-Motion Interfaculty Center (CiMIC), Münster, Germany
- Center for Soft Nanoscience, Münster, Germany
| | - Yaroslav Tsytsyura
- Institute for Medical Physics and Biophysics, and Cells-in-Motion Interfaculty Center (CiMIC), Münster, Germany
| | - Nataliya Glyvuk
- Institute for Medical Physics and Biophysics, and Cells-in-Motion Interfaculty Center (CiMIC), Münster, Germany
| | - Annegret Elting
- Institute of Cell Dynamics and Imaging, and Cells-in-Motion Interfaculty Center (CiMIC), University of Münster, Münster, Germany
| | - Julia Wittmar
- Institute of Cell Dynamics and Imaging, and Cells-in-Motion Interfaculty Center (CiMIC), University of Münster, Münster, Germany
| | - Annette Janning
- Institute of Cell Dynamics and Imaging, and Cells-in-Motion Interfaculty Center (CiMIC), University of Münster, Münster, Germany
| | - Martin Kahms
- Institute for Medical Physics and Biophysics, and Cells-in-Motion Interfaculty Center (CiMIC), Münster, Germany
| | - Noah Wedlich
- Institute of Cell Dynamics and Imaging, and Cells-in-Motion Interfaculty Center (CiMIC), University of Münster, Münster, Germany
- Institute for Physical Chemistry, Münster, Germany
| | - Christian Schuberth
- Institute of Cell Dynamics and Imaging, and Cells-in-Motion Interfaculty Center (CiMIC), University of Münster, Münster, Germany
| | | | - Jürgen Klingauf
- Institute for Medical Physics and Biophysics, and Cells-in-Motion Interfaculty Center (CiMIC), Münster, Germany
- Center for Soft Nanoscience, Münster, Germany
| | - Roland Wedlich-Söldner
- Institute of Cell Dynamics and Imaging, and Cells-in-Motion Interfaculty Center (CiMIC), University of Münster, Münster, Germany
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4
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Kono Y, Ishibashi Y, Fukuda S, Higuchi T, Tani M. Simultaneous structural replacement of the sphingoid long-chain base and sterol in budding yeast. FEBS J 2023; 290:5605-5627. [PMID: 37690108 DOI: 10.1111/febs.16949] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 07/25/2023] [Accepted: 09/05/2023] [Indexed: 09/12/2023]
Abstract
The basic structures of membrane lipids that compose biomembranes differ among species; i.e., in mammals, the primary structure of long-chain base (LCB), the common backbone of ceramides and complex sphingolipids, is sphingosine, whereas, in yeast Saccharomyces cerevisiae, it is phytosphingosine, and S. cerevisiae does not have sphingosine. In addition, the sterol, which is coordinately involved in various functions with complex sphingolipids, is cholesterol in mammals, while in yeast it is ergosterol. Previously, it was found that yeast cells are viable when the structure of LCBs is replaced by sphingosine by supplying an exogenous LCB to cells lacking LCB biosynthesis. Here, we characterized yeast cells having sphingosine instead of phytosphingosine (sphingosine cells). Sphingosine cells exhibited a strong growth defect when biosynthesis of ceramides or complex sphingolipids was inhibited, indicating that, in the sphingosine cells, exogenously added sphingosine is required to be further metabolized. The sphingosine cells exhibited hypersensitivity to various environmental stresses and had abnormal plasma membrane and cell wall properties. Furthermore, we also established a method for simultaneous replacement of both LCB and sterol structures with those of mammals (sphingosine/cholesterol cells). The multiple stress hypersensitivity and abnormal plasma membrane and cell wall properties observed in sphingosine cells were also observed in sphingosine/cholesterol cells, suggesting that simultaneous replacement of both LCB and sterol structures with those of mammals cannot prevent these abnormal phenotypes. This is the first study to our knowledge showing that S. cerevisiae can grow even if LCB and sterol structures are simultaneously replaced with mammalian types.
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Affiliation(s)
- Yushi Kono
- Department of Chemistry, Faculty of Sciences, Kyushu University, Fukuoka, Japan
| | - Yohei Ishibashi
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Fukuoka, Japan
| | - Shizuka Fukuda
- Department of Chemistry, Faculty of Sciences, Kyushu University, Fukuoka, Japan
| | - Takashi Higuchi
- Department of Chemistry, Faculty of Sciences, Kyushu University, Fukuoka, Japan
| | - Motohiro Tani
- Department of Chemistry, Faculty of Sciences, Kyushu University, Fukuoka, Japan
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5
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Courtin B, Namane A, Gomard M, Meyer L, Jacquier A, Fromont-Racine M. Xrn1 biochemically associates with eisosome proteins after the post diauxic shift in yeast. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000926. [PMID: 37746059 PMCID: PMC10514700 DOI: 10.17912/micropub.biology.000926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/29/2023] [Accepted: 08/31/2023] [Indexed: 09/26/2023]
Abstract
mRNA degradation is one of the main steps of gene expression, and a key player is the 5'-3' exonuclease Xrn1. In Saccharomyces cerevisiae , it was previously shown, by a microscopy approach, that Xrn1 is located to different cellular compartments, depending on physiological state. During exponential growth, Xrn1 is distributed in the cytoplasm, while it co-localizes with eisosomes after the post-diauxic shift (PDS). Here, we biochemically characterize the Xrn1-associated complexes in different cellular states. We demonstrate that, after PDS, Xrn1 but not the decapping nor Lsm1-7/Pat1 complexes associates with eisosomal proteins, strengthening the model that sequestration of Xrn1 in eisosomes preserves mRNAs from degradation during PDS.
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Affiliation(s)
- Baptiste Courtin
- Institut Pasteur, Cytoplasmic mRNA surveillance in yeast, Centre National de la Recherche Scientifique, UMR 3525, 75724 Paris Cedex 15, France
| | - Abdelkader Namane
- Institut Pasteur, Cytoplasmic mRNA surveillance in yeast, Centre National de la Recherche Scientifique, UMR 3525, 75724 Paris Cedex 15, France
| | - Maite Gomard
- Institut Pasteur, Cytoplasmic mRNA surveillance in yeast, Centre National de la Recherche Scientifique, UMR 3525, 75724 Paris Cedex 15, France
| | - Laura Meyer
- Institut Pasteur, Cytoplasmic mRNA surveillance in yeast, Centre National de la Recherche Scientifique, UMR 3525, 75724 Paris Cedex 15, France
| | - Alain Jacquier
- Institut Pasteur, Cytoplasmic mRNA surveillance in yeast, Centre National de la Recherche Scientifique, UMR 3525, 75724 Paris Cedex 15, France
| | - Micheline Fromont-Racine
- Institut Pasteur, Cytoplasmic mRNA surveillance in yeast, Centre National de la Recherche Scientifique, UMR 3525, 75724 Paris Cedex 15, France
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6
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Caligaris M, Sampaio-Marques B, Hatakeyama R, Pillet B, Ludovico P, De Virgilio C, Winderickx J, Nicastro R. The Yeast Protein Kinase Sch9 Functions as a Central Nutrient-Responsive Hub That Calibrates Metabolic and Stress-Related Responses. J Fungi (Basel) 2023; 9:787. [PMID: 37623558 PMCID: PMC10455444 DOI: 10.3390/jof9080787] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 07/20/2023] [Accepted: 07/24/2023] [Indexed: 08/26/2023] Open
Abstract
Yeast cells are equipped with different nutrient signaling pathways that enable them to sense the availability of various nutrients and adjust metabolism and growth accordingly. These pathways are part of an intricate network since most of them are cross-regulated and subject to feedback regulation at different levels. In yeast, a central role is played by Sch9, a protein kinase that functions as a proximal effector of the conserved growth-regulatory TORC1 complex to mediate information on the availability of free amino acids. However, recent studies established that Sch9 is more than a TORC1-effector as its activity is tuned by several other kinases. This allows Sch9 to function as an integrator that aligns different input signals to achieve accuracy in metabolic responses and stress-related molecular adaptations. In this review, we highlight the latest findings on the structure and regulation of Sch9, as well as its role as a nutrient-responsive hub that impacts on growth and longevity of yeast cells. Given that most key players impinging on Sch9 are well-conserved, we also discuss how studies on Sch9 can be instrumental to further elucidate mechanisms underpinning healthy aging in mammalians.
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Affiliation(s)
- Marco Caligaris
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland; (M.C.); (B.P.); (C.D.V.)
| | - Belém Sampaio-Marques
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (B.S.-M.); (P.L.)
- ICVS/3B’s-PT Government Associate Laboratory, 4806-909 Guimarães, Portugal
| | - Riko Hatakeyama
- Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK;
| | - Benjamin Pillet
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland; (M.C.); (B.P.); (C.D.V.)
| | - Paula Ludovico
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal; (B.S.-M.); (P.L.)
- ICVS/3B’s-PT Government Associate Laboratory, 4806-909 Guimarães, Portugal
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland; (M.C.); (B.P.); (C.D.V.)
| | - Joris Winderickx
- Department of Biology, Functional Biology, KU Leuven, B-3001 Heverlee, Belgium;
| | - Raffaele Nicastro
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland; (M.C.); (B.P.); (C.D.V.)
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7
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Vesela P, Zahumensky J, Malinsky J. Lsp1 partially substitutes for Pil1 function in eisosome assembly under stress conditions. J Cell Sci 2023; 136:286927. [PMID: 36601791 DOI: 10.1242/jcs.260554] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 12/22/2022] [Indexed: 01/06/2023] Open
Abstract
Eisosomes are large hemitubular structures that underlie the invaginated microdomains in the plasma membrane of various ascomycetous fungi, lichens and unicellular algae. In fungi, they are organized by BAR-domain containing proteins of the Pil1 family. Two such proteins, Pil1 and Lsp1, participate in eisosome formation in the yeast Saccharomyces cerevisiae. Under normal laboratory conditions, deletion of the PIL1 gene results in the inability of cells to assemble wild-type-like eisosomes. We found that under certain stress conditions, Lsp1 partially substitutes for the Pil1 function and mediates assembly of eisosomes, specifically following a decrease in the activity of serine palmitoyltransferase, for example, in response to hyperosmotic stress. Besides Lsp1, the assembly of eisosomes lacking Pil1 also requires Seg1 and Nce102 proteins. Using next-generation sequencing, we found that the seg1Δnce102Δpil1Δ strain, which is unable to form eisosomes, overexpresses genes coding for proteins of oxidative phosphorylation and tricarboxylic acid cycle. By contrast, genes involved in DNA repair, ribosome biogenesis and cell cycle are downregulated. Our results identify Lsp1 as a stress-responsive eisosome organizer and indicate several novel functional connections between the eisosome and essential cellular processes.
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Affiliation(s)
- Petra Vesela
- Department of Functional Organization of Biomembranes, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 142 20 Prague, Czech Republic
| | - Jakub Zahumensky
- Department of Functional Organization of Biomembranes, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 142 20 Prague, Czech Republic
| | - Jan Malinsky
- Department of Functional Organization of Biomembranes, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 142 20 Prague, Czech Republic
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8
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Kollath-Leiß K, Yang Q, Winter H, Kempken F. Complementation of an Eisosomal Yeast pil1 Mutant and Characteristics of Eisosomal Distribution in Hyphae of Neurospora crassa Germinating from Two Different Spore Types. J Fungi (Basel) 2023; 9:jof9020147. [PMID: 36836262 PMCID: PMC9964885 DOI: 10.3390/jof9020147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 01/13/2023] [Accepted: 01/15/2023] [Indexed: 01/24/2023] Open
Abstract
Eisosomes are plasma-membrane-associated protein complexes of fungi and algae involved in various cellular processes. The eisosome composition of the budding yeast is well described, but there is a limited number of studies only about eisosomes in filamentous fungi. In our study, we examined the Neurospora crassa LSP-1 protein (NcLSP1). By complementing a Saccharomyces cerevisiae Δpil1 mutant strain with nclsp1, we show the functional homology of the NcLSP1 to yeast PIL1 rather than to yeast LSP1 and hereby confirm that the NcLSP1 is an eisosomal core protein and suitable eisosomal marker. The subsequent cloning and expression of the nclsp1::trfp reporter gene construct in N. crassa allowed for a systematical investigation of the characteristics of eisosome formation and distribution in different developmental stages. In N. crassa, the hyphae germinating from sexual and asexual spores are morphologically identical and have been historically recognized as the same type of cells. Here, we demonstrate the structural differences on the cellular level between the hyphae germinating from sexual and asexual spores.
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9
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Koga A, Takayama C, Ishibashi Y, Kono Y, Matsuzaki M, Tani M. Loss of tolerance to multiple environmental stresses due to limitation of structural diversity of complex sphingolipids. Mol Biol Cell 2022; 33:ar105. [PMID: 35895092 DOI: 10.1091/mbc.e22-04-0117] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Structural diversity of complex sphingolipids is important for maintenance of various cellular functions; however, the overall picture of the significance of this structural diversity remains largely unknown. To investigate the physiological importance of the structural diversity of complex sphingolipids, we here constructed a complex sphingolipid structural diversity disruption library in budding yeast, which comprises 11 mutants including with combinations of deletions of sphingolipid-metabolizing enzyme genes. The sensitivity of the mutants to various environmental stresses revealed that the more the structural variation of complex sphingolipids is limited, the more stress sensitivity tends to increase. Moreover, it was found that in mutant cells with only one subtype of complex sphingolipid, Slt2 MAP kinase and Msn2/4 transcriptional factors are essential for maintenance of a normal growth and compensation for reduced tolerance of multiple stresses caused by loss of complex sphingolipid diversity. Slt2 and Msn2/4 are involved in compensation for impaired integrity of cell walls and plasma membranes caused by loss of complex sphingolipid diversity, respectively. From these findings, it was suggested that loss of structural diversity of complex sphingolipids affects the environment of the cell surface, including both plasma membranes and cell walls, which could cause multiple environmental stress hypersensitivity.
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Affiliation(s)
- Ayano Koga
- Department of Chemistry, Faculty of Sciences, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Chihiro Takayama
- Department of Chemistry, Faculty of Sciences, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yohei Ishibashi
- Department of Bioscience and Biotechnology, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Yushi Kono
- Department of Chemistry, Faculty of Sciences, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Momoko Matsuzaki
- Department of Chemistry, Faculty of Sciences, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
| | - Motohiro Tani
- Department of Chemistry, Faculty of Sciences, Kyushu University, Nishi-ku, Fukuoka 819-0395, Japan
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10
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Pal A, Paripati A, Deolal P, Chatterjee A, Prasad PR, Adla P, Sepuri NBV. Eisosome protein Pil1 regulates mitochondrial morphology, mitophagy, and cell death in Saccharomyces cerevisiae. J Biol Chem 2022; 298:102533. [PMID: 36162502 PMCID: PMC9619184 DOI: 10.1016/j.jbc.2022.102533] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 09/18/2022] [Accepted: 09/19/2022] [Indexed: 12/06/2022] Open
Abstract
Mitochondrial morphology and dynamics maintain mitochondrial integrity by regulating its size, shape, distribution, and connectivity, thereby modulating various cellular processes. Several studies have established a functional link between mitochondrial dynamics, mitophagy, and cell death, but further investigation is needed to identify specific proteins involved in mitochondrial dynamics. Any alteration in the integrity of mitochondria has severe ramifications that include disorders like cancer and neurodegeneration. In this study, we used budding yeast as a model organism and found that Pil1, the major component of the eisosome complex, also localizes to the periphery of mitochondria. Interestingly, the absence of Pil1 causes the branched tubular morphology of mitochondria to be abnormally fused or aggregated, whereas its overexpression leads to mitochondrial fragmentation. Most importantly, pil1Δ cells are defective in mitophagy and bulk autophagy, resulting in elevated levels of reactive oxygen species and protein aggregates. In addition, we show that pil1Δ cells are more prone to cell death. Yeast two-hybrid analysis and co-immunoprecipitations show the interaction of Pil1 with two major proteins in mitochondrial fission, Fis1 and Dnm1. Additionally, our data suggest that the role of Pil1 in maintaining mitochondrial shape is dependent on Fis1 and Dnm1, but it functions independently in mitophagy and cell death pathways. Together, our data suggest that Pil1, an eisosome protein, is a novel regulator of mitochondrial morphology, mitophagy, and cell death.
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Affiliation(s)
- Amita Pal
- Department of Biochemistry, University of Hyderabad, Prof. C.R Rao Road, Gachibowli, Hyderabad, TS -500046
| | - Arunkumar Paripati
- Department of Biochemistry, University of Hyderabad, Prof. C.R Rao Road, Gachibowli, Hyderabad, TS -500046
| | - Pallavi Deolal
- Department of Biochemistry, University of Hyderabad, Prof. C.R Rao Road, Gachibowli, Hyderabad, TS -500046
| | - Arpan Chatterjee
- Department of Biochemistry, University of Hyderabad, Prof. C.R Rao Road, Gachibowli, Hyderabad, TS -500046
| | - Pushpa Rani Prasad
- Department of Biochemistry, University of Hyderabad, Prof. C.R Rao Road, Gachibowli, Hyderabad, TS -500046
| | - Priyanka Adla
- Department of Biochemistry, University of Hyderabad, Prof. C.R Rao Road, Gachibowli, Hyderabad, TS -500046
| | - Naresh Babu V Sepuri
- Department of Biochemistry, University of Hyderabad, Prof. C.R Rao Road, Gachibowli, Hyderabad, TS -500046.
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11
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Substrates of the MAPK Slt2: Shaping Yeast Cell Integrity. J Fungi (Basel) 2022; 8:jof8040368. [PMID: 35448599 PMCID: PMC9031059 DOI: 10.3390/jof8040368] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 02/04/2023] Open
Abstract
The cell wall integrity (CWI) MAPK pathway of budding yeast Saccharomyces cerevisiae is specialized in responding to cell wall damage, but ongoing research shows that it participates in many other stressful conditions, suggesting that it has functional diversity. The output of this pathway is mainly driven by the activity of the MAPK Slt2, which regulates important processes for yeast physiology such as fine-tuning of signaling through the CWI and other pathways, transcriptional activation in response to cell wall damage, cell cycle, or determination of the fate of some organelles. To this end, Slt2 precisely phosphorylates protein substrates, modulating their activity, stability, protein interaction, and subcellular localization. Here, after recapitulating the methods that have been employed in the discovery of proteins phosphorylated by Slt2, we review the bona fide substrates of this MAPK and the growing set of candidates still to be confirmed. In the context of the complexity of MAPK signaling regulation, we discuss how Slt2 determines yeast cell integrity through phosphorylation of these substrates. Increasing data from large-scale analyses and the available methodological approaches pave the road to early identification of new Slt2 substrates and functions.
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12
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Plasma Membrane Furrows Control Plasticity of ER-PM Contacts. Cell Rep 2021; 30:1434-1446.e7. [PMID: 32023460 DOI: 10.1016/j.celrep.2019.12.098] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 11/14/2019] [Accepted: 12/27/2019] [Indexed: 01/10/2023] Open
Abstract
The plasma membrane (PM) forms extensive close junctions with the cortical endoplasmic reticulum (cER) in many cell types, ranging from yeast to mammals. How cells modulate structural plasticity of ER-PM contacts to accommodate space-demanding cortical events is largely unknown. Here, we report a role for eisosome-driven PM furrows in regulating ER-PM contact plasticity in fission yeast. We demonstrate that eisosome-coated PM invaginations function to stabilize local ER-PM contacts and attenuate cER remodeling dynamics through electrostatic Scs2-Pil1 interactions. We also identify divergent roles of ER-shaping proteins in controlling cER remodeling capacity and ER-PM contact plasticity. Furthermore, we show that eisosome organization is responsive to PM tension variations during active PM remodeling, which may enable adaptive control of ER-PM contact plasticity to potentially coordinate with space-demanding PM events. We thus propose a cellular strategy of modulating membrane contact plasticity by deploying sensory elements at contact sites.
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13
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Jain BK, Roland BP, Graham TR. Exofacial membrane composition and lipid metabolism regulates plasma membrane P4-ATPase substrate specificity. J Biol Chem 2020; 295:17997-18009. [PMID: 33060204 PMCID: PMC7939387 DOI: 10.1074/jbc.ra120.014794] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 09/22/2020] [Indexed: 01/21/2023] Open
Abstract
The plasma membrane of a cell is characterized by an asymmetric distribution of lipid species across the exofacial and cytofacial aspects of the bilayer. Regulation of membrane asymmetry is a fundamental characteristic of membrane biology and is crucial for signal transduction, vesicle transport, and cell division. The type IV family of P-ATPases, or P4-ATPases, establishes membrane asymmetry by selection and transfer of a subset of membrane lipids from the lumenal or exofacial leaflet to the cytofacial aspect of the bilayer. It is unclear how P4-ATPases sort through the spectrum of membrane lipids to identify their desired substrate(s) and how the membrane environment modulates this activity. Therefore, we tested how the yeast plasma membrane P4-ATPase, Dnf2, responds to changes in membrane composition induced by perturbation of endogenous lipid biosynthetic pathways or exogenous application of lipid. The primary substrates of Dnf2 are glucosylceramide (GlcCer) and phosphatidylcholine (PC, or their lyso-lipid derivatives), and we find that these substrates compete with each other for transport. Acutely inhibiting sphingolipid synthesis using myriocin attenuates transport of exogenously applied GlcCer without perturbing PC transport. Deletion of genes controlling later steps of glycosphingolipid production also perturb GlcCer transport to a greater extent than PC transport. In contrast, perturbation of ergosterol biosynthesis reduces PC and GlcCer transport equivalently. Surprisingly, application of lipids that are poor transport substrates differentially affects PC and GlcCer transport by Dnf2, thus altering substrate preference. Our data indicate that Dnf2 exhibits exquisite sensitivity to the membrane composition, thus providing feedback onto the function of the P4-ATPases.
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Affiliation(s)
- Bhawik Kumar Jain
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Bartholomew P Roland
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Todd R Graham
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA.
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14
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Anti-angiogenesis and apoptogenic potential of the brown marine alga, Chnoospora minima. FUTURE JOURNAL OF PHARMACEUTICAL SCIENCES 2020. [DOI: 10.1186/s43094-020-00039-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Algae being one of the dominant organisms in nature can provide best opportunity for the discovery of new anti-cancer drugs. The aim of the present study was to investigate the anti-cancer and anti-angiogenic potential of the brown marine alga Chnoospora minima.
Result
The methanol extract of C. minima and its bioactive fraction (CF4) have highly significant cytotoxic effects to HepG2, HeLa and MCF-7 cancer cell lines. The fraction’s ability to induce apoptosis in the cancer cells was evidenced by increased caspase activity (caspase-3, 7 and 10), DNA fragmentation pattern and upregulated expressions of Bax and p53 genes. The bioactive fraction was not toxic to human peripheral lymphocytes. HPLC, ESI-MS and GC-MS analysis of CF4 fraction indicated the presence of the compound hexadecanoic acid which might be responsible for the observed anti-cancer activity of C. minima. The methanol extract of C. minima exhibited anti-angiogenic effects on chick embryos.
Conclusion
It can be concluded that fraction, CF4, from C. minima is a promising source of an anti-cancer lead molecule.
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Plasma Membrane MCC/Eisosome Domains Promote Stress Resistance in Fungi. Microbiol Mol Biol Rev 2020; 84:84/4/e00063-19. [PMID: 32938742 DOI: 10.1128/mmbr.00063-19] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
There is growing appreciation that the plasma membrane orchestrates a diverse array of functions by segregating different activities into specialized domains that vary in size, stability, and composition. Studies with the budding yeast Saccharomyces cerevisiae have identified a novel type of plasma membrane domain known as the MCC (membrane compartment of Can1)/eisosomes that correspond to stable furrows in the plasma membrane. MCC/eisosomes maintain proteins at the cell surface, such as nutrient transporters like the Can1 arginine symporter, by protecting them from endocytosis and degradation. Recent studies from several fungal species are now revealing new functional roles for MCC/eisosomes that enable cells to respond to a wide range of stressors, including changes in membrane tension, nutrition, cell wall integrity, oxidation, and copper toxicity. The different MCC/eisosome functions are often intertwined through the roles of these domains in lipid homeostasis, which is important for proper plasma membrane architecture and cell signaling. Therefore, this review will emphasize the emerging models that explain how MCC/eisosomes act as hubs to coordinate cellular responses to stress. The importance of MCC/eisosomes is underscored by their roles in virulence for fungal pathogens of plants, animals, and humans, which also highlights the potential of these domains to act as novel therapeutic targets.
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Song J, Liu X, Li R. Sphingolipids: Regulators of azole drug resistance and fungal pathogenicity. Mol Microbiol 2020; 114:891-905. [PMID: 32767804 DOI: 10.1111/mmi.14586] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 07/29/2020] [Accepted: 08/02/2020] [Indexed: 12/14/2022]
Abstract
In recent years, the role of sphingolipids in pathogenic fungi, in terms of pathogenicity and resistance to azole drugs, has been a rapidly growing field. This review describes evidence about the roles of sphingolipids in azole resistance and fungal virulence. Sphingolipids can serve as signaling molecules that contribute to azole resistance through modulation of the expression of drug efflux pumps. They also contribute to azole resistance by participating in various microbial pathways such as the unfolded protein response (UPR), pH-responsive Rim pathway, and pleiotropic drug resistance (PDR) pathway. In addition, sphingolipid signaling and eisosomes also coordinately regulate sphingolipid biosynthesis in response to azole-induced membrane stress. Sphingolipids are important for fungal virulence, playing roles during growth in hosts under stressful conditions, maintenance of cell wall integrity, biofilm formation, and production of various virulence factors. Finally, we discuss the possibility of exploiting fungal sphingolipids for the development of new therapeutic strategies to treat infections caused by pathogenic fungi.
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Affiliation(s)
- Jinxing Song
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou, PR China
| | - Xiao Liu
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou, PR China
| | - Rongpeng Li
- The Key Laboratory of Biotechnology for Medicinal Plants of Jiangsu Province and School of Life Science, Jiangsu Normal University, Xuzhou, PR China
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17
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Athanasopoulos A, André B, Sophianopoulou V, Gournas C. Fungal plasma membrane domains. FEMS Microbiol Rev 2020; 43:642-673. [PMID: 31504467 DOI: 10.1093/femsre/fuz022] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Accepted: 08/25/2019] [Indexed: 12/11/2022] Open
Abstract
The plasma membrane (PM) performs a plethora of physiological processes, the coordination of which requires spatial and temporal organization into specialized domains of different sizes, stability, protein/lipid composition and overall architecture. Compartmentalization of the PM has been particularly well studied in the yeast Saccharomyces cerevisiae, where five non-overlapping domains have been described: The Membrane Compartments containing the arginine permease Can1 (MCC), the H+-ATPase Pma1 (MCP), the TORC2 kinase (MCT), the sterol transporters Ltc3/4 (MCL), and the cell wall stress mechanosensor Wsc1 (MCW). Additional cortical foci at the fungal PM are the sites where clathrin-dependent endocytosis occurs, the sites where the external pH sensing complex PAL/Rim localizes, and sterol-rich domains found in apically grown regions of fungal membranes. In this review, we summarize knowledge from several fungal species regarding the organization of the lateral PM segregation. We discuss the mechanisms of formation of these domains, and the mechanisms of partitioning of proteins there. Finally, we discuss the physiological roles of the best-known membrane compartments, including the regulation of membrane and cell wall homeostasis, apical growth of fungal cells and the newly emerging role of MCCs as starvation-protective membrane domains.
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Affiliation(s)
- Alexandros Athanasopoulos
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research 'Demokritos,' Patr. Grigoriou E & 27 Neapoleos St. 15341, Agia Paraskevi, Greece
| | - Bruno André
- Molecular Physiology of the Cell laboratory, Université Libre de Bruxelles (ULB), Institut de Biologie et de Médecine Moléculaires, rue des Pr Jeener et Brachet 12, 6041, Gosselies, Belgium
| | - Vicky Sophianopoulou
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research 'Demokritos,' Patr. Grigoriou E & 27 Neapoleos St. 15341, Agia Paraskevi, Greece
| | - Christos Gournas
- Microbial Molecular Genetics Laboratory, Institute of Biosciences and Applications, National Centre for Scientific Research 'Demokritos,' Patr. Grigoriou E & 27 Neapoleos St. 15341, Agia Paraskevi, Greece
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18
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Riggi M, Kusmider B, Loewith R. The flipside of the TOR coin - TORC2 and plasma membrane homeostasis at a glance. J Cell Sci 2020; 133:133/9/jcs242040. [PMID: 32393676 DOI: 10.1242/jcs.242040] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Target of rapamycin (TOR) is a serine/threonine protein kinase conserved in most eukaryote organisms. TOR assembles into two multiprotein complexes (TORC1 and TORC2), which function as regulators of cellular growth and homeostasis by serving as direct transducers of extracellular biotic and abiotic signals, and, through their participation in intrinsic feedback loops, respectively. TORC1, the better-studied complex, is mainly involved in cell volume homeostasis through regulating accumulation of proteins and other macromolecules, while the functions of the lesser-studied TORC2 are only now starting to emerge. In this Cell Science at a Glance article and accompanying poster, we aim to highlight recent advances in our understanding of TORC2 signalling, particularly those derived from studies in yeast wherein TORC2 has emerged as a major regulator of cell surface homeostasis.
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Affiliation(s)
- Margot Riggi
- Swiss National Centre for Competence in Research Program Chemical Biology, Geneva, Switzerland.,Department of Biochemistry, University of Geneva, Geneva, Switzerland.,Department of Molecular Biology, University of Geneva, Geneva, Switzerland
| | - Beata Kusmider
- Swiss National Centre for Competence in Research Program Chemical Biology, Geneva, Switzerland.,Department of Molecular Biology, University of Geneva, Geneva, Switzerland
| | - Robbie Loewith
- Swiss National Centre for Competence in Research Program Chemical Biology, Geneva, Switzerland .,Department of Molecular Biology, University of Geneva, Geneva, Switzerland
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19
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Guo Q, Zhang T, Meng N, Duan Y, Meng Y, Sun D, Liu Y, Luo G. Sphingolipids are required for exocyst polarity and exocytic secretion in Saccharomyces cerevisiae. Cell Biosci 2020; 10:53. [PMID: 32257111 PMCID: PMC7106735 DOI: 10.1186/s13578-020-00406-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Accepted: 03/10/2020] [Indexed: 11/13/2022] Open
Abstract
Background Exocytosis is a process by which vesicles are transported to and fused with specific areas of the plasma membrane. Although several studies have shown that sphingolipids are the main components of exocytic compartments, whether they control exocytosis process is unclear. Results Here, we have investigated the role of sphingolipids in exocytosis by reducing the activity of the serine palmitoyl-transferase (SPT), which catalyzes the first step in sphingolipid synthesis in endoplasmic reticulum. We found that the exocyst polarity and exocytic secretion were impaired in lcb1-100 mutant cells and in wild type cells treated with myriocin, a chemical which can specifically inhibit SPT enzyme activity, suggesting that sphingolipids controls exocytic secretion. This speculation was further confirmed by immuno-fluorescence and electron microscopy results that small secretory vesicles were accumulated in lcb1-100 mutant cells. Conclusions Taken together, our results suggest that sphingolipids are required for exocytosis. Mammals may use similar regulatory mechanisms because components of the exocytic secretion apparatus and signaling pathways are conserved.
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Affiliation(s)
- Qingguo Guo
- 1Institute of Translational Medicine, China Medical University, Shenyang, 110122 China.,2Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, 110122 China
| | - Tianrui Zhang
- 2Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, 110122 China
| | - Na Meng
- 2Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, 110122 China
| | - Yuran Duan
- 2Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, 110122 China
| | - Yuan Meng
- 2Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, 110122 China
| | - Dong Sun
- 1Institute of Translational Medicine, China Medical University, Shenyang, 110122 China
| | - Ying Liu
- 2Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, 110122 China
| | - Guangzuo Luo
- 1Institute of Translational Medicine, China Medical University, Shenyang, 110122 China
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20
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Amen T, Kaganovich D. Stress granules sense metabolic stress at the plasma membrane and potentiate recovery by storing active Pkc1. Sci Signal 2020; 13:13/623/eaaz6339. [DOI: 10.1126/scisignal.aaz6339] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
As the physical barrier between the cell and the outside environment, the plasma membrane is well-positioned to be the first responder to stress. The membrane is also highly vulnerable to many types of perturbation, including heat, force, osmotic pressure, lipid shortage, and starvation. To determine whether the structural changes in the plasma membrane of Saccharomyces cerevisiae brought about by nutrient stress can be communicated to regulatory networks within the cell, we identified proteins that interact with stress granules (SGs), subcellular structures composed of proteins, and nontranslated RNAs that form when cells are stressed. We found that SG proteins interacted with components of eisosomes, which are subcortical membrane structures with a distinct lipid and protein composition. In response to starvation-triggered phosphorylation of eisosome proteins, eisosomes clustered and recruited SG components, including active Pkc1. The absence of eisosomes impaired SG formation, resulting in delayed recovery from nutrient deprivation. Thus, eisosome clustering is an example of interdomain communication in response to stress and identifies a previously unknown mechanism of SG regulation.
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Affiliation(s)
- Triana Amen
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
| | - Daniel Kaganovich
- Department of Experimental Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
- 1Base Pharmaceuticals, Boston, MA 02129, USA
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21
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Colou J, N'Guyen GQ, Dubreu O, Fontaine K, Kwasiborski A, Bastide F, Manero F, Hamon B, Aligon S, Simoneau P, Guillemette T. Role of membrane compartment occupied by Can1 (MCC) and eisosome subdomains in plant pathogenicity of the necrotrophic fungus Alternaria brassicicola. BMC Microbiol 2019; 19:295. [PMID: 31842747 PMCID: PMC6916069 DOI: 10.1186/s12866-019-1667-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Accepted: 11/28/2019] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND MCC/eisosomes are membrane microdomains that have been proposed to participate in the plasma membrane function in particular by regulating the homeostasis of lipids, promoting the recruitment of specific proteins and acting as provider of membrane reservoirs. RESULTS Here we showed that several potential MCC/eisosomal protein encoding genes in the necrotrophic fungus A. brassicicola were overexpressed when germinated spores were exposed to antimicrobial defence compounds, osmotic and hydric stresses, which are major constraints encountered by the fungus during the plant colonization process. Mutants deficient for key MCC/eisosome components did not exhibit any enhanced susceptibility to phytoalexins and to applied stress conditions compared to the reference strain, except for a slight hypersensitivity of the ∆∆abpil1a-abpil1b strain to 2 M sorbitol. Depending on the considered mutants, we showed that the leaf and silique colonization processes were impaired by comparison to the wild-type, and assumed that these defects in aggressiveness were probably caused by a reduced appressorium formation rate. CONCLUSIONS This is the first study on the role of MCC/eisosomes in the pathogenic process of a plant pathogenic fungus. A link between these membrane domains and the fungus ability to form functional penetration structures was shown, providing new potential directions for plant disease control strategies.
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Affiliation(s)
- Justine Colou
- Institut de Recherche en Horticulture et Semences - UMR 1345, INRA, Université d'Angers, Agrocampus-Ouest, SFR 4207 QuaSaV, 42 rue Georges Morel, 49071 Beaucouzé Cedex, Angers, France
| | - Guillaume Quang N'Guyen
- Institut de Recherche en Horticulture et Semences - UMR 1345, INRA, Université d'Angers, Agrocampus-Ouest, SFR 4207 QuaSaV, 42 rue Georges Morel, 49071 Beaucouzé Cedex, Angers, France.,Institut de Biologie Intégrative et des Systèmes, Département de Biologie, PROTEO, Université Laval, Pavillon Charles-Eugène-Marchand, 1030 Avenue de la Médecine, QC, Québec, G1V 0A6, Canada
| | - Ophélie Dubreu
- Institut de Recherche en Horticulture et Semences - UMR 1345, INRA, Université d'Angers, Agrocampus-Ouest, SFR 4207 QuaSaV, 42 rue Georges Morel, 49071 Beaucouzé Cedex, Angers, France
| | - Kévin Fontaine
- Institut de Recherche en Horticulture et Semences - UMR 1345, INRA, Université d'Angers, Agrocampus-Ouest, SFR 4207 QuaSaV, 42 rue Georges Morel, 49071 Beaucouzé Cedex, Angers, France.,ANSES, Laboratoire de la Santé des Végétaux, Unité de Mycologie, Domaine de Pixérécourt, 54220, Malzéville, France
| | - Anthony Kwasiborski
- Institut de Recherche en Horticulture et Semences - UMR 1345, INRA, Université d'Angers, Agrocampus-Ouest, SFR 4207 QuaSaV, 42 rue Georges Morel, 49071 Beaucouzé Cedex, Angers, France
| | - Franck Bastide
- Institut de Recherche en Horticulture et Semences - UMR 1345, INRA, Université d'Angers, Agrocampus-Ouest, SFR 4207 QuaSaV, 42 rue Georges Morel, 49071 Beaucouzé Cedex, Angers, France
| | - Florence Manero
- Plateforme SCIAM, Institut de Biologie en Santé, CHU, Université d'Angers, 4, Rue Larrey, 49933, Angers Cedex, France
| | - Bruno Hamon
- Institut de Recherche en Horticulture et Semences - UMR 1345, INRA, Université d'Angers, Agrocampus-Ouest, SFR 4207 QuaSaV, 42 rue Georges Morel, 49071 Beaucouzé Cedex, Angers, France
| | - Sophie Aligon
- Institut de Recherche en Horticulture et Semences - UMR 1345, INRA, Université d'Angers, Agrocampus-Ouest, SFR 4207 QuaSaV, 42 rue Georges Morel, 49071 Beaucouzé Cedex, Angers, France
| | - Philippe Simoneau
- Institut de Recherche en Horticulture et Semences - UMR 1345, INRA, Université d'Angers, Agrocampus-Ouest, SFR 4207 QuaSaV, 42 rue Georges Morel, 49071 Beaucouzé Cedex, Angers, France
| | - Thomas Guillemette
- Institut de Recherche en Horticulture et Semences - UMR 1345, INRA, Université d'Angers, Agrocampus-Ouest, SFR 4207 QuaSaV, 42 rue Georges Morel, 49071 Beaucouzé Cedex, Angers, France.
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Abstract
Melanins are dark green, brown, or black pigments that serve as antioxidant, reactive oxygen species (ROS) scavengers that protect fungal pathogens from radiation and host immune responses. Cryptococcus neoformans, the major etiological agent of fungal meningoencephalitis, also utilizes melanin as a key virulence factor. In this basidiomycete pathogen, melanin production is regulated by the cAMP and high-osmolarity glycerol response (HOG) pathways, and yet its complex signaling networks remain poorly described. In this study, we uncovered novel melanin synthesis regulatory networks consisting of core transcription factors (TFs), including Bzp4, Usv101, Hob1, and Mbs1, and core kinases Gsk3 and Kic1. These networks were identified through coupling systematic analyses of the expression and epistatic relationships of TF and kinase mutant libraries in the presence of diverse melanin substrates with transcriptome profiling of the core TF mutants. Thus, this report provides comprehensive insight into the melanin-regulating pathways in C. neoformans and other fungal pathogens. Melanin is an antioxidant polyphenol pigment required for the pathogenicity of many fungal pathogens, but comprehensive regulatory mechanisms remain unidentified. In this study, we systematically analyzed melanin-regulating signaling pathways in Cryptococcus neoformans and identified four melanin-regulating core transcription factors (TFs), Bzp4, Usv101, Mbs1, and Hob1, required for induction of the laccase gene (LAC1). Bzp4, Usv101, and Mbs1 independently regulate LAC1 induction, whereas Hob1 controls Bzp4 and Usv101 expression. Both Bzp4 and Usv101 are localized in the cytoplasm under nutrient-rich conditions (i.e., in the presence of yeast extract-peptone-dextrose [YPD] medium) but translocate into the nucleus upon nutrient starvation (i.e., in the presence of yeast nitrogen base [YNB] medium without glucose), and Mbs1 is constitutively localized in the nucleus. Notably, the cAMP pathway is not involved in regulation of the four TFs, but the high-osmolarity glycerol response (HOG) pathway negatively regulates induction of BZP4 and LAC1. Next, we searched for potential kinases upstream of the core TFs and identified nine core kinases; their deletion led to defective melanin production and LAC1 induction. Deletion of GSK3 or KIC1 abolished induction of LAC1 and BZP4 and perturbed nuclear translocation of Bzp4. Notably, Gsk3 also regulated expression of HOB1, USV101, and MBS1, indicating that it is a critical melanin-regulating kinase. Finally, an RNA sequencing-based transcriptome analysis of the wild-type strain and of bzp4Δ, usv101Δ, hob1Δ, and mbs1Δ strains under nutrient-rich and nutrient-starved conditions revealed that the melanin-regulating core TFs govern redundant and distinct classes of genes involved in a variety of biological processes.
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Zahumensky J, Malinsky J. Role of MCC/Eisosome in Fungal Lipid Homeostasis. Biomolecules 2019; 9:E305. [PMID: 31349700 PMCID: PMC6723945 DOI: 10.3390/biom9080305] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 07/19/2019] [Accepted: 07/22/2019] [Indexed: 12/11/2022] Open
Abstract
One of the best characterized fungal membrane microdomains is the MCC/eisosome. The MCC (membrane compartment of Can1) is an evolutionarily conserved ergosterol-rich plasma membrane domain. It is stabilized on its cytosolic face by the eisosome, a hemitubular protein complex composed of Bin/Amphiphysin/Rvs (BAR) domain-containing Pil1 and Lsp1. These two proteins bind directly to phosphatidylinositol 4,5-bisphosphate and promote the typical furrow-like shape of the microdomain, with highly curved edges and bottom. While some proteins display stable localization in the MCC/eisosome, others enter or leave it under particular conditions, such as misbalance in membrane lipid composition, changes in membrane tension, or availability of specific nutrients. These findings reveal that the MCC/eisosome, a plasma membrane microdomain with distinct morphology and lipid composition, acts as a multifaceted regulator of various cellular processes including metabolic pathways, cellular morphogenesis, signalling cascades, and mRNA decay. In this minireview, we focus on the MCC/eisosome's proposed role in the regulation of lipid metabolism. While the molecular mechanisms of the MCC/eisosome function are not completely understood, the idea of intracellular processes being regulated at the plasma membrane, the foremost barrier exposed to environmental challenges, is truly exciting.
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Affiliation(s)
- Jakub Zahumensky
- Department of Microscopy, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic
| | - Jan Malinsky
- Department of Microscopy, Institute of Experimental Medicine, Academy of Sciences of the Czech Republic, 14220 Prague, Czech Republic.
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24
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Babst M. Eisosomes at the intersection of TORC1 and TORC2 regulation. Traffic 2019; 20:543-551. [PMID: 31038844 DOI: 10.1111/tra.12651] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/24/2019] [Accepted: 04/26/2019] [Indexed: 12/14/2022]
Abstract
Eisosomes are furrows in the yeast plasma membrane that form a membrane domain with distinct lipid and protein composition. Recent studies highlighted the importance of this domain for the regulation of proton-nutrient symporters. The amino acids and other nutrients, which these transporters deliver to the cytoplasm not only feed into metabolic pathways but also activate the metabolic regulator TORC1. Eisosomes have also been shown to harbor the membrane stress sensors Slm1 and Slm2. Membrane tension caused by hypoosmotic shock results in the redistribution of Slm1/2 from eisosomes to TORC2 which in turn regulates lipid synthesis. Therefore, eisosomes function upstream of both TORC1 and TORC2 regulation.
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Affiliation(s)
- Markus Babst
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, Utah
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Yu SC, Kuemmel F, Skoufou-Papoutsaki MN, Spanu PD. Yeast transformation efficiency is enhanced by TORC1- and eisosome-dependent signaling. Microbiologyopen 2018; 8:e00730. [PMID: 30311441 PMCID: PMC6528558 DOI: 10.1002/mbo3.730] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 08/09/2018] [Accepted: 08/10/2018] [Indexed: 12/12/2022] Open
Abstract
Transformation of baker's yeast (Saccharomyces cerevisiae) plays a key role in several experimental techniques, yet the molecular mechanisms underpinning transformation are still unclear. The addition of amino acids to the growth and transformation medium increases transformation efficiency. Here, we show that target of rapamycin complex 1 (TORC1) activated by amino acids enhances transformation via ubiquitin‐mediated endocytosis. We created mutants of the TORC1 pathway, alpha‐arrestins, and eisosome‐related genes. Our results demonstrate that the TORC1‐Npr1‐Art1/Rsp5 pathway regulates yeast transformation. Based on our previous study, activation of this pathway results in up to a 200‐fold increase in transformation efficiency, or greater. Additionally, we suggest DNA may be taken up by domains at the membrane compartment of Can1 (MCC) in the plasma membrane formed by eisosomes. Yeast studies on transformation could be used as a platform to understand the mechanism of DNA uptake in mammalian systems, which is clinically relevant to optimize gene therapy.
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Affiliation(s)
- Sheng-Chun Yu
- Department of Life Sciences, Imperial College London, London, UK
| | - Florian Kuemmel
- Department of Life Sciences, Imperial College London, London, UK
| | | | - Pietro D Spanu
- Department of Life Sciences, Imperial College London, London, UK
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26
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Moharir A, Gay L, Appadurai D, Keener J, Babst M. Eisosomes are metabolically regulated storage compartments for APC-type nutrient transporters. Mol Biol Cell 2018; 29:2113-2127. [PMID: 29927345 PMCID: PMC6232963 DOI: 10.1091/mbc.e17-11-0691] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Eisosomes are lipid domains of the yeast plasma membrane that share similarities to caveolae of higher eukaryotes. Eisosomes harbor APC-type nutrient transporters for reasons that are poorly understood. Our analyses support the model that eisosomes function as storage compartments, keeping APC transporters in a stable, inactive state. By regulating eisosomes, yeast is able to balance the number of proton-driven APC transporters with the proton-pumping activity of Pma1, thereby maintaining the plasma membrane proton gradient. Environmental or metabolic changes that disrupt the proton gradient cause the rapid restructuring of eisosomes and results in the removal of the APC transporters from the cell surface. Furthermore, we show evidence that eisosomes require the presence of APC transporters, suggesting that regulating activity of nutrient transporters is a major function of eisosomes.
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Affiliation(s)
- Akshay Moharir
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
| | - Lincoln Gay
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
| | - Daniel Appadurai
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
| | - James Keener
- Department of Mathematics, University of Utah, Salt Lake City, UT 84112
| | - Markus Babst
- Henry Eyring Center for Cell and Genome Science, University of Utah, Salt Lake City, UT 84112
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Rodríguez-Escudero I, Fernández-Acero T, Cid VJ, Molina M. Heterologous mammalian Akt disrupts plasma membrane homeostasis by taking over TORC2 signaling in Saccharomyces cerevisiae. Sci Rep 2018; 8:7732. [PMID: 29769614 PMCID: PMC5955888 DOI: 10.1038/s41598-018-25717-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/26/2018] [Indexed: 01/21/2023] Open
Abstract
The Akt protein kinase is the main transducer of phosphatidylinositol-3,4,5-trisphosphate (PtdIns3,4,5P3) signaling in higher eukaryotes, controlling cell growth, motility, proliferation and survival. By co-expression of mammalian class I phosphatidylinositol 3-kinase (PI3K) and Akt in the Saccharomyces cerevisiae heterologous model, we previously described an inhibitory effect on yeast growth that relied on Akt kinase activity. Here we report that PI3K-Akt expression in yeast triggers the formation of large plasma membrane (PM) invaginations that were marked by actin patches, enriched in PtdIns4,5P2 and associated to abnormal intracellular cell wall deposits. These effects of Akt were mimicked by overproduction of the PtdIns4,5P2 effector Slm1, an adaptor of the Ypk1 and Ypk2 kinases in the TORC2 pathway. Although Slm1 was phosphorylated in vivo by Akt, TORC2-dependent Ypk1 activation did not occur. However, PI3K-activated Akt suppressed the lethality derived from inactivation of either TORC2 or Ypk protein kinases. Thus, heterologous co-expression of PI3K and Akt in yeast short-circuits PtdIns4,5P2- and TORC2-signaling at the level of the Slm-Ypk complex, overriding some of its functions. Our results underscore the importance of phosphoinositide-dependent kinases as key actors in the homeostasis and dynamics of the PM.
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Affiliation(s)
- Isabel Rodríguez-Escudero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Madrid, Spain
| | - Teresa Fernández-Acero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Madrid, Spain
| | - Víctor J Cid
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Madrid, Spain.
| | - María Molina
- Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigaciones Sanitarias, Madrid, Spain
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Ma Y, Liang S, Zhang Y, Yang D, Wang R. Development of anti-fungal pesticides from protein kinase inhibitor-based anticancer agents. Eur J Med Chem 2018; 148:349-358. [DOI: 10.1016/j.ejmech.2018.02.040] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 02/11/2018] [Accepted: 02/12/2018] [Indexed: 11/25/2022]
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MCC/Eisosomes Regulate Cell Wall Synthesis and Stress Responses in Fungi. J Fungi (Basel) 2017; 3:jof3040061. [PMID: 29371577 PMCID: PMC5753163 DOI: 10.3390/jof3040061] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 10/26/2017] [Accepted: 10/31/2017] [Indexed: 12/20/2022] Open
Abstract
The fungal plasma membrane is critical for cell wall synthesis and other important processes including nutrient uptake, secretion, endocytosis, morphogenesis, and response to stress. To coordinate these diverse functions, the plasma membrane is organized into specialized compartments that vary in size, stability, and composition. One recently identified domain known as the Membrane Compartment of Can1 (MCC)/eisosome is distinctive in that it corresponds to a furrow-like invagination in the plasma membrane. MCC/eisosomes have been shown to be formed by the Bin/Amphiphysin/Rvs (BAR) domain proteins Lsp1 and Pil1 in a range of fungi. MCC/eisosome domains influence multiple cellular functions; but a very pronounced defect in cell wall synthesis has been observed for mutants with defects in MCC/eisosomes in some yeast species. For example, Candida albicans MCC/eisosome mutants display abnormal spatial regulation of cell wall synthesis, including large invaginations and altered chemical composition of the walls. Recent studies indicate that MCC/eisosomes affect cell wall synthesis in part by regulating the levels of the key regulatory lipid phosphatidylinositol 4,5-bisphosphate (PI4,5P2) in the plasma membrane. One general way MCC/eisosomes function is by acting as protected islands in the plasma membrane, since these domains are very stable. They also act as scaffolds to recruit >20 proteins. Genetic studies aimed at defining the function of the MCC/eisosome proteins have identified important roles in resistance to stress, such as resistance to oxidative stress mediated by the flavodoxin-like proteins Pst1, Pst2, Pst3 and Ycp4. Thus, MCC/eisosomes play multiple roles in plasma membrane organization that protect fungal cells from the environment.
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30
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Heinisch JJ, Rodicio R. Protein kinase C in fungi—more than just cell wall integrity. FEMS Microbiol Rev 2017; 42:4562651. [DOI: 10.1093/femsre/fux051] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/19/2017] [Indexed: 11/13/2022] Open
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Winters CM, Hong-Brown LQ, Chiang HL. The Shape of Vesicle-Containing Organelles Is Critical for Their Functions in Vesicle Endocytosis. DNA Cell Biol 2017; 36:909-921. [PMID: 29040005 DOI: 10.1089/dna.2017.3847] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Exosomes are small vesicles secreted by a variety of cell types under physiological and pathological conditions. When Saccharomyces cerevisiae are grown in low glucose, small vesicles carrying more than 300 proteins with diverse biological functions are secreted. Upon glucose addition, secreted vesicles are endocytosed that requires cup-shaped organelles containing the major eisosome protein Pil1p at the rims. We aim to identify genes that regulate the function of cup-shaped organelles in vesicle endocytosis. In cells lacking either VID27 or VID21, Pil1p distribution was altered and cup-shaped organelles became elongated with narrower openings. Change in shape reduced the number of vesicles in the deeper areas and impaired vesicle endocytosis. Vid21p and Vid27p were localized to vesicle clusters and interacted with other Vid proteins. In the absence of these genes, these vesicles failed to aggregate and were secreted. Vid21p and Vid27p are required for the aggregation and retention of vesicles that contain Vid proteins in the cytoplasm. Increased vesicles near the plasma membrane in mutant strains correlate with an increased Pil1p movement resulting in the fusion of cup-shaped organelles. We conclude that the shape of vesicle-containing organelles is critical for their functions in vesicle endocytosis.
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Affiliation(s)
- Chelsea M Winters
- Department of Cellular and Molecular Physiology, Penn State University College of Medicine , Hershey, Pennsylvania
| | - Ly Q Hong-Brown
- Department of Cellular and Molecular Physiology, Penn State University College of Medicine , Hershey, Pennsylvania
| | - Hui-Ling Chiang
- Department of Cellular and Molecular Physiology, Penn State University College of Medicine , Hershey, Pennsylvania
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The TORC2-Dependent Signaling Network in the Yeast Saccharomyces cerevisiae. Biomolecules 2017; 7:biom7030066. [PMID: 28872598 PMCID: PMC5618247 DOI: 10.3390/biom7030066] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 08/25/2017] [Accepted: 08/28/2017] [Indexed: 12/21/2022] Open
Abstract
To grow, eukaryotic cells must expand by inserting glycerolipids, sphingolipids, sterols, and proteins into their plasma membrane, and maintain the proper levels and bilayer distribution. A fungal cell must coordinate growth with enlargement of its cell wall. In Saccharomyces cerevisiae, a plasma membrane-localized protein kinase complex, Target of Rapamicin (TOR) complex-2 (TORC2) (mammalian ortholog is mTORC2), serves as a sensor and master regulator of these plasma membrane- and cell wall-associated events by directly phosphorylating and thereby stimulating the activity of two types of effector protein kinases: Ypk1 (mammalian ortholog is SGK1), along with a paralog (Ypk2); and, Pkc1 (mammalian ortholog is PKN2/PRK2). Ypk1 is a central regulator of pathways and processes required for plasma membrane lipid and protein homeostasis, and requires phosphorylation on its T-loop by eisosome-associated protein kinase Pkh1 (mammalian ortholog is PDK1) and a paralog (Pkh2). For cell survival under various stresses, Ypk1 function requires TORC2-mediated phosphorylation at multiple sites near its C terminus. Pkc1 controls diverse processes, especially cell wall synthesis and integrity. Pkc1 is also regulated by Pkh1- and TORC2-dependent phosphorylation, but, in addition, by interaction with Rho1-GTP and lipids phosphatidylserine (PtdSer) and diacylglycerol (DAG). We also describe here what is currently known about the downstream substrates modulated by Ypk1-mediated and Pkc1-mediated phosphorylation.
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33
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Vaškovičová K, Awadová T, Veselá P, Balážová M, Opekarová M, Malinsky J. mRNA decay is regulated via sequestration of the conserved 5′-3′ exoribonuclease Xrn1 at eisosome in yeast. Eur J Cell Biol 2017; 96:591-599. [DOI: 10.1016/j.ejcb.2017.05.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/07/2017] [Accepted: 05/02/2017] [Indexed: 01/08/2023] Open
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Stein K, Winters C, Chiang HL. Vps15p regulates the distribution of cup-shaped organelles containing the major eisosome protein Pil1p to the extracellular fraction required for endocytosis of extracellular vesicles carrying metabolic enzymes. Biol Cell 2017; 109:190-209. [PMID: 28248428 DOI: 10.1111/boc.201600060] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 02/20/2017] [Accepted: 02/23/2017] [Indexed: 11/30/2022]
Abstract
BACKGROUND INFORMATION Exosomes are small vesicles secreted from virtually every cell from bacteria to humans. Saccharomyces cerevisiae is a model system to study trafficking of small vesicles in response to changes in the environment. When yeast cells are grown in low glucose, vesicles carrying gluconeogenic enzymes are present as free vesicles and aggregated clusters in the cytoplasm. These vesicles are also secreted into the periplasm and account for more than 90% of total extracellular organelles, while less than 10% are larger 100-300 nm structures with unknown functions. When glucose is added to glucose-starved cells, secreted vesicles are endocytosed and then targeted to the vacuole. Recent secretomic studies indicated that more than 300 proteins involved in diverse biological functions are secreted during glucose starvation and endocytosed during glucose re-feeding. We hypothesised that extracellular vesicles are internalised using novel mechanisms independent of clathrin-mediated endocytosis. RESULTS Our results showed that vesicles carrying metabolic enzymes were endocytosed at a fast rate, whereas vesicles carrying the heat shock protein Ssa1p were endocytosed at a slow rate. The PI3K regulator Vps15p is critical for the fast internalisation of extracellular vesicles. VPS15 regulates the distribution of the 100-300 nm organelles that contain the major eisosome protein Pil1p to the extracellular fraction. These Pil1p-containing structures were purified and showed unique cup-shape with their centres deeper than the peripheries. In the absence of VPS15, PIL1 or when PIL1 was mutated, the 100-300 nm structures were not observed in the extracellular fraction and the rapid internalisation of vesicles was impaired. CONCLUSIONS We conclude that VPS15 regulates the distribution of the 100-300 nm Pil1p-containing organelles to the extracellular fraction required for fast endocytosis of vesicles carrying metabolic enzymes. This work provides the first evidence showing that Pil1p displayed unique distribution patterns in the intracellular and extracellular fractions. This work also demonstrates that endocytosis of vesicles is divided into a fast and a slow pathway. The fast pathway is the predominant pathway and is used by vesicles carrying metabolic enzymes. Cup-shaped Pil1p-containing structures are critical for the rapid endocytosis of vesicles into the cytoplasm. SIGNIFICANCE This work provides the first evidence showing that Pil1p displayed unique distribution patterns in the intracellular and extracellular fractions. This work also demonstrates that endocytosis of vesicles is divided into a fast and a slow pathway. The fast pathway is the predominant pathway and is used by vesicles carrying metabolic enzymes. Cup-shaped Pil1p-containing structures are critical for the rapid endocytosis of vesicles into the cytoplasm.
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Affiliation(s)
- Kathryn Stein
- Department of Cellular and Molecular Physiology, Penn State University College of Medicine, Hershey, PA, 17033, USA
| | - Chelsea Winters
- Department of Cellular and Molecular Physiology, Penn State University College of Medicine, Hershey, PA, 17033, USA
| | - Hui-Ling Chiang
- Department of Cellular and Molecular Physiology, Penn State University College of Medicine, Hershey, PA, 17033, USA
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35
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Zhang LB, Tang L, Ying SH, Feng MG. Two eisosome proteins play opposite roles in autophagic control and sustain cell integrity, function and pathogenicity in Beauveria bassiana. Environ Microbiol 2017; 19:2037-2052. [DOI: 10.1111/1462-2920.13727] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Revised: 03/02/2017] [Accepted: 03/03/2017] [Indexed: 01/06/2023]
Affiliation(s)
- Long-Bin Zhang
- Institute of Microbiology, College of Life Sciences; Zhejiang University; Hangzhou Zhejiang 310058 People's Republic of China
| | - Li Tang
- Institute of Microbiology, College of Life Sciences; Zhejiang University; Hangzhou Zhejiang 310058 People's Republic of China
| | - Sheng-Hua Ying
- Institute of Microbiology, College of Life Sciences; Zhejiang University; Hangzhou Zhejiang 310058 People's Republic of China
| | - Ming-Guang Feng
- Institute of Microbiology, College of Life Sciences; Zhejiang University; Hangzhou Zhejiang 310058 People's Republic of China
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36
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Kim HJ, Jeong MY, Parnell TJ, Babst M, Phillips JD, Winge DR. The Plasma Membrane Protein Nce102 Implicated in Eisosome Formation Rescues a Heme Defect in Mitochondria. J Biol Chem 2016; 291:17417-26. [PMID: 27317660 DOI: 10.1074/jbc.m116.727743] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Indexed: 11/06/2022] Open
Abstract
The cellular transport of the cofactor heme and its biosynthetic intermediates such as protoporphyrin IX is a complex and highly coordinated process. To investigate the molecular details of this trafficking pathway, we created a synthetic lesion in the heme biosynthetic pathway by deleting the gene HEM15 encoding the enzyme ferrochelatase in S. cerevisiae and performed a genetic suppressor screen. Cells lacking Hem15 are respiratory-defective because of an inefficient heme delivery to the mitochondria. Thus, the biogenesis of mitochondrial cytochromes is negatively affected. The suppressor screen resulted in the isolation of respiratory-competent colonies containing two distinct missense mutations in Nce102, a protein that localizes to plasma membrane invaginations designated as eisosomes. The presence of the Nce102 mutant alleles enabled formation of the mitochondrial respiratory complexes and respiratory growth in hem15Δ cells cultured in supplemental hemin. Respiratory function in hem15Δ cells can also be restored by the presence of a heterologous plasma membrane heme permease (HRG-4), but the mode of suppression mediated by the Nce102 mutant is more efficient. Attenuation of the endocytic pathway through deletion of the gene END3 impaired the Nce102-mediated rescue, suggesting that the Nce102 mutants lead to suppression through the yeast endocytic pathway.
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Affiliation(s)
- Hyung J Kim
- From the Departments of Medicine and Biochemistry, University of Utah Health Sciences Center, Salt Lake City, Utah 84132
| | - Mi-Young Jeong
- From the Departments of Medicine and Biochemistry, University of Utah Health Sciences Center, Salt Lake City, Utah 84132
| | - Timothy J Parnell
- the Huntsman Cancer Institute, Bioinformatics Shared Resources, Salt Lake City, Utah 84132, and
| | - Markus Babst
- the Department of Biology and Center for Cell and Genomic Science, University of Utah, Salt Lake City, Utah 84112
| | - John D Phillips
- From the Departments of Medicine and Biochemistry, University of Utah Health Sciences Center, Salt Lake City, Utah 84132
| | - Dennis R Winge
- From the Departments of Medicine and Biochemistry, University of Utah Health Sciences Center, Salt Lake City, Utah 84132,
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TORC2 and eisosomes are spatially interdependent, requiring optimal level of phosphatidylinositol 4, 5-bisphosphate for their integrity. J Biosci 2016; 40:299-311. [PMID: 25963258 DOI: 10.1007/s12038-015-9526-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The elucidation of the organization and maintenance of the plasma membrane has been sought due to its numerous roles in cellular function. In the budding yeast Saccharomyces cerevisiae, a novel paradigm has begun to emerge in the understanding of the distribution of plasma membrane microdomains and how they are regulated. We aimed to investigate the dynamic interdependence between the protein complexes eisosome and TORC2, representing microdomains MCC and MCT, respectively. In this study, we reveal that the eisosome organizer Pil1 colocalizes with the MCT marker Avo2. Furthermore, we provide evidence that the formation of MCT is dependent on both eisosome integrity and adequate levels of the plasma membrane phosphoinositide PI(4,5)P2. Taken together, our findings indicate that TORC2, eisosomes, and PI(4,5)P2 exist in an interconnected relationship, which supports the emerging model of the plasma membrane.
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García-Marqués S, Randez-Gil F, Dupont S, Garre E, Prieto JA. Sng1 associates with Nce102 to regulate the yeast Pkh-Ypk signalling module in response to sphingolipid status. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1319-33. [PMID: 27033517 DOI: 10.1016/j.bbamcr.2016.03.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Revised: 03/09/2016] [Accepted: 03/23/2016] [Indexed: 11/30/2022]
Abstract
All cells are delimited by biological membranes, which are consequently a primary target of stress-induced damage. Cold alters membrane functionality by decreasing lipid fluidity and the activity of membrane proteins. In Saccharomyces cerevisiae, evidence links sphingolipid homeostasis and membrane phospholipid asymmetry to the activity of the Ypk1/2 proteins, the yeast orthologous of the mammalian SGK1-3 kinases. Their regulation is mediated by different protein kinases, including the PDK1 orthologous Pkh1/2p, and requires the function of protein effectors, among them Nce102p, a component of the sphingolipid sensor machinery. Nevertheless, the mechanisms and the actors involved in Pkh/Ypk regulation remain poorly defined. Here, we demonstrate that Sng1, a transmembrane protein, is an effector of the Pkh/Ypk module and identify the phospholipid asymmetry as key for yeast cold adaptation. Overexpression of SNG1 impairs phospholipid flipping, reduces reactive oxygen species (ROS) and improves, in a Pkh-dependent manner, yeast growth in myriocin-treated cells, suggesting that excess Sng1p stimulates the Pkh/Ypk signalling. Furthermore, we link these effects to the association of Sng1p with Nce102p. Indeed, we found that Sng1p interacts with Nce102p both physically and genetically. Moreover, mutant nce102∆ sng1∆ cells show features of impaired Pkh/Ypk signalling, including increased ROS accumulation, reduced life span and defects in Pkh/Ypk-controlled regulatory pathways. Finally, myriocin-induced hyperphosphorylation of Ypk1p and Orm2p, which controls sphingolipid homeostasis, does not occur in nce102∆ sng1∆ cells. Hence, both Nce102p and Sng1p participate in a regulatory circuit that controls the activity of the Pkh/Ypk module and their function is required in response to sphingolipid status.
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Affiliation(s)
- Sara García-Marqués
- Department of Biotechnology, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, Avda. Agustín Escardino, 7. 46980, Paterna, Valencia, Spain
| | - Francisca Randez-Gil
- Department of Biotechnology, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, Avda. Agustín Escardino, 7. 46980, Paterna, Valencia, Spain
| | - Sebastien Dupont
- UMR Procédés Alimentaires et Microbiologiques (PAM), AgroSup Dijon/Université de Bourgogne 1, Esplanade Erasme, 21000, Dijon, France
| | - Elena Garre
- Department of Biotechnology, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, Avda. Agustín Escardino, 7. 46980, Paterna, Valencia, Spain
| | - Jose A Prieto
- Department of Biotechnology, Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas, Avda. Agustín Escardino, 7. 46980, Paterna, Valencia, Spain.
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New Insight Into the Roles of Membrane Microdomains in Physiological Activities of Fungal Cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 325:119-80. [PMID: 27241220 DOI: 10.1016/bs.ircmb.2016.02.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The organization of biological membranes into structurally and functionally distinct lateral microdomains is generally accepted. From bacteria to mammals, laterally compartmentalized membranes seem to be a vital attribute of life. The crucial fraction of our current knowledge about the membrane microdomains has been gained from studies on fungi. In this review we summarize the evidence of the microdomain organization of membranes from fungal cells, with accent on their enormous diversity in composition, temporal dynamics, modes of formation, and recognized engagement in the cell physiology. A special emphasis is laid on the fact that in addition to their other biological functions, membrane microdomains also mediate the communication among different membranes within a eukaryotic cell and coordinate their functions. Involvement of fungal membrane microdomains in stress sensing, regulation of lipid homeostasis, and cell differentiation is discussed more in detail.
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40
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Douglas LM, Konopka JB. Plasma membrane organization promotes virulence of the human fungal pathogen Candida albicans. J Microbiol 2016; 54:178-91. [PMID: 26920878 DOI: 10.1007/s12275-016-5621-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2015] [Revised: 01/15/2016] [Accepted: 01/15/2016] [Indexed: 12/21/2022]
Abstract
Candida albicans is a human fungal pathogen capable of causing lethal systemic infections. The plasma membrane plays key roles in virulence because it not only functions as a protective barrier, it also mediates dynamic functions including secretion of virulence factors, cell wall synthesis, invasive hyphal morphogenesis, endocytosis, and nutrient uptake. Consistent with this functional complexity, the plasma membrane is composed of a wide array of lipids and proteins. These components are organized into distinct domains that will be the topic of this review. Some of the plasma membrane domains that will be described are known to act as scaffolds or barriers to diffusion, such as MCC/eisosomes, septins, and sites of contact with the endoplasmic reticulum. Other zones mediate dynamic processes, including secretion, endocytosis, and a special region at hyphal tips that facilitates rapid growth. The highly organized architecture of the plasma membrane facilitates the coordination of diverse functions and promotes the pathogenesis of C. albicans.
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Affiliation(s)
- Lois M Douglas
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, 11794-5222, USA
| | - James B Konopka
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, NY, 11794-5222, USA.
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41
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Villasmil ML, Francisco J, Gallo-Ebert C, Donigan M, Liu HY, Brower M, Nickels JT. Ceramide signals for initiation of yeast mating-specific cell cycle arrest. Cell Cycle 2016; 15:441-54. [PMID: 26726837 DOI: 10.1080/15384101.2015.1127475] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Sphingolipids are major constituents of membranes. A number of S. cerevisiae sphingolipid intermediates such as long chains sphingoid bases (LCBs) and ceramides act as signaling molecules regulating cell cycle progression, adaptability to heat stress, and survival in response to starvation. Here we show that S. cerevisiae haploid cells must synthesize ceramide in order to induce mating specific cell cycle arrest. Cells devoid of sphingolipid biosynthesis or defective in ceramide synthesis are sterile and harbor defects in pheromone-induced MAP kinase-dependent transcription. Analyses of G1/S cyclin levels indicate that mutant cells cannot reduce Cln1/2 levels in response to pheromone. FACS analysis indicates a lack of ability to arrest. The addition of LCBs to sphingolipid deficient cells restores MAP kinase-dependent transcription, reduces cyclin levels, and allows for mating, as does the addition of a cell permeable ceramide to cells blocked at ceramide synthesis. Pharmacological studies using the inositolphosphorylceramide synthase inhibitor aureobasidin A indicate that the ability to synthesize and accumulate ceramide alone is sufficient for cell cycle arrest and mating. Studies indicate that ceramide also has a role in PI(4,5)P2 polarization during mating, an event necessary for initiating cell cycle arrest and mating itself. Moreover, our studies suggest a third role for ceramide in localizing the mating-specific Ste5 scaffold to the plasma membrane. Thus, ceramide plays a role 1) in pheromone-induced cell cycle arrest, 2) in activation of MAP kinase-dependent transcription, and 3) in PtdIns(4,5)P2 polarization. All three events are required for differentiation during yeast mating.
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Affiliation(s)
- Michelle L Villasmil
- a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA.,b Cato Research Ltd. , Durham , NC , USA
| | - Jamie Francisco
- a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA
| | - Christina Gallo-Ebert
- a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA
| | - Melissa Donigan
- a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA
| | - Hsing-Yin Liu
- a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA
| | - Melody Brower
- a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA.,c Synthes, Inc , Paoli , PA , USA
| | - Joseph T Nickels
- a The Institute of Metabolic Disorders, Genesis Biotechnology Group , Hamilton , NJ , USA
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Olivera-Couto A, Salzman V, Mailhos M, Digman MA, Gratton E, Aguilar PS. Eisosomes are dynamic plasma membrane domains showing pil1-lsp1 heteroligomer binding equilibrium. Biophys J 2016; 108:1633-1644. [PMID: 25863055 PMCID: PMC4390835 DOI: 10.1016/j.bpj.2015.02.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 01/28/2015] [Accepted: 02/12/2015] [Indexed: 12/11/2022] Open
Abstract
Eisosomes are plasma membrane domains concentrating lipids, transporters, and signaling molecules. In the budding yeast Saccharomyces cerevisiae, these domains are structured by scaffolds composed mainly by two cytoplasmic proteins Pil1 and Lsp1. Eisosomes are immobile domains, have relatively uniform size, and encompass thousands of units of the core proteins Pil1 and Lsp1. In this work we used fluorescence fluctuation analytical methods to determine the dynamics of eisosome core proteins at different subcellular locations. Using a combination of scanning techniques with autocorrelation analysis, we show that Pil1 and Lsp1 cytoplasmic pools freely diffuse whereas an eisosome-associated fraction of these proteins exhibits slow dynamics that fit with a binding-unbinding equilibrium. Number and brightness analysis shows that the eisosome-associated fraction is oligomeric, while cytoplasmic pools have lower aggregation states. Fluorescence lifetime imaging results indicate that Pil1 and Lsp1 directly interact in the cytoplasm and within the eisosomes. These results support a model where Pil1-Lsp1 heterodimers are the minimal eisosomes building blocks. Moreover, individual-eisosome fluorescence fluctuation analysis shows that eisosomes in the same cell are not equal domains: while roughly half of them are mostly static, the other half is actively exchanging core protein subunits.
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Affiliation(s)
- Agustina Olivera-Couto
- Laboratorio de Biología Celular de Membranas, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Valentina Salzman
- Laboratorio de Biología Celular de Membranas, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Milagros Mailhos
- Laboratorio de Biología Celular de Membranas, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Michelle A Digman
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California-Irvine, Irvine, California; Centre for Bioactive Discovery in Health and Ageing, School of Science and Technology, University of New England, Armidale, Australia
| | - Enrico Gratton
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering, University of California-Irvine, Irvine, California.
| | - Pablo S Aguilar
- Laboratorio de Biología Celular de Membranas, Institut Pasteur de Montevideo, Montevideo, Uruguay.
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Pastor-Flores D, Schulze JO, Bahí A, Süß E, Casamayor A, Biondi RM. Lipid regulators of Pkh2 in Candida albicans, the protein kinase ortholog of mammalian PDK1. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1861:249-59. [PMID: 26743850 DOI: 10.1016/j.bbalip.2015.12.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 12/21/2015] [Accepted: 12/24/2015] [Indexed: 11/18/2022]
Abstract
Pkh is the yeast ortholog of the mammalian 3-phosphoinositide-dependent protein kinase 1 (PDK1). Pkh phosphorylates the activation loop of Ypks, Tpks, Sch9 and also phosphorylates the eisosome components Lsp1 and Pil1, which play fundamental roles upstream of diverse signaling pathways, including the cell wall integrity and sphingosine/long-chain base (LCB) signaling pathways. In S. cerevisiae, two isoforms, ScPkh1 and ScPkh2, are required for cell viability, while only one ortholog exists in C. albicans, CaPkh2. In spite of the extensive information gathered on the role of Pkh in the LCB signaling, the yeast Pkh kinases are not known to bind lipids and previous studies did not identify PH domains in Pkh sequences. We now describe that the C-terminal region of CaPkh2 is required for its intrinsic kinase activity. In addition, we found that the C-terminal region of CaPkh2 enables its interaction with structural and signaling lipids. Our results further show that phosphatidylserine, phosphatidic acid, phosphatidylinositol (3,4 and 4,5)-biphosphates, and phosphatidylinositol (3,4,5)-trisphosphate inhibit Pkh activity, whereas sulfatide binds with high affinity but does not affect the intrinsic activity of CaPkh2. Interestingly, we identified that its human ortholog PDK1 also binds to sulfatide. We propose a mechanism by which lipids and dihydrosphingosine regulate CaPkh2 kinase activity by modulating the interaction of the C-terminal region with the kinase domain, while sulfatide-like lipids support localization CaPkh2 mediated by a C-terminal PH domain, without affecting kinase intrinsic activity.
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Affiliation(s)
- Daniel Pastor-Flores
- Research Group PhosphoSites, Medizinische Klinik 1, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Jörg O Schulze
- Research Group PhosphoSites, Medizinische Klinik 1, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Anna Bahí
- Departament de Bioquímica i Biologia Molecular, Facultat de Veterinària, Universitat Autònoma de Barcelona, Cerdanyola, 08193, Barcelona, Spain; Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola, 08193, Barcelona, Spain
| | - Evelyn Süß
- Research Group PhosphoSites, Medizinische Klinik 1, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Antonio Casamayor
- Departament de Bioquímica i Biologia Molecular, Facultat de Veterinària, Universitat Autònoma de Barcelona, Cerdanyola, 08193, Barcelona, Spain; Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola, 08193, Barcelona, Spain.
| | - Ricardo M Biondi
- Research Group PhosphoSites, Medizinische Klinik 1, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
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Teixeira V, Costa V. Unraveling the role of the Target of Rapamycin signaling in sphingolipid metabolism. Prog Lipid Res 2015; 61:109-33. [PMID: 26703187 DOI: 10.1016/j.plipres.2015.11.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 11/04/2015] [Accepted: 11/09/2015] [Indexed: 02/06/2023]
Abstract
Sphingolipids are important bioactive molecules that regulate basic aspects of cellular metabolism and physiology, including cell growth, adhesion, migration, senescence, apoptosis, endocytosis, and autophagy in yeast and higher eukaryotes. Since they have the ability to modulate the activation of several proteins and signaling pathways, variations in the relative levels of different sphingolipid species result in important changes in overall cellular functions and fate. Sphingolipid metabolism and their route of synthesis are highly conserved from yeast to mammalian cells. Studies using the budding yeast Saccharomyces cerevisiae have served in many ways to foster our understanding of sphingolipid dynamics and their role in the regulation of cellular processes. In the past decade, studies in S. cerevisiae have unraveled a functional association between the Target of Rapamycin (TOR) pathway and sphingolipids, showing that both TOR Complex 1 (TORC1) and TOR Complex 2 (TORC2) branches control temporal and spatial aspects of sphingolipid metabolism in response to physiological and environmental cues. In this review, we report recent findings in this emerging and exciting link between the TOR pathway and sphingolipids and implications in human health and disease.
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Affiliation(s)
- Vitor Teixeira
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Porto, Portugal; ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Departamento de Biologia Molecular, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal
| | - Vítor Costa
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Rua Alfredo Allen, 208, 4200-135 Porto, Portugal; IBMC, Instituto de Biologia Molecular e Celular, Porto, Portugal; ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Departamento de Biologia Molecular, Universidade do Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
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Characterization of AnNce102 and its role in eisosome stability and sphingolipid biosynthesis. Sci Rep 2015; 5:15200. [PMID: 26468899 PMCID: PMC4606592 DOI: 10.1038/srep15200] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 09/21/2015] [Indexed: 12/26/2022] Open
Abstract
The plasma membrane is implicated in a variety of functions, whose coordination necessitates highly dynamic organization of its constituents into domains of distinct protein and lipid composition. Eisosomes, at least partially, mediate this lateral plasma membrane compartmentalization. In this work, we show that the Nce102 homologue of Aspergillus nidulans colocalizes with eisosomes and plays a crucial role in density/number of PilA/SurG foci in the head of germlings. In addition we demonstrate that AnNce102 and PilA negatively regulate sphingolipid biosynthesis, since their deletions partially suppress the thermosensitivity of basA mutant encoding sphingolipid C4-hydroxylase and the growth defects observed upon treatment with inhibitors of sphingolipid biosynthesis, myriocin and Aureobasidin A. Moreover, we show that YpkA repression mimics genetic or pharmacological depletion of sphingolipids, conditions that induce the production of Reactive Oxygen Species (ROS), and can be partially overcome by deletion of pilA and/or annce102 at high temperatures. Consistent with these findings, pilAΔ and annce102Δ also show differential sensitivity to various oxidative agents, while AnNce102 overexpression can bypass sphingolipid depletion regarding the PilA/SurG foci number and organization, also leading to the mislocalization of PilA to septa.
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Pastor-Flores D, Ferrer-Dalmau J, Bahí A, Boleda M, Biondi RM, Casamayor A. Depletion of yeast PDK1 orthologs triggers a stress-like transcriptional response. BMC Genomics 2015; 16:719. [PMID: 26391581 PMCID: PMC4578605 DOI: 10.1186/s12864-015-1903-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 09/09/2015] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Pkh proteins are the PDK1 orthologs in S. cerevisiae. They have redundant and essential activity and are responsible for the phosphorylation of several members of the AGC family of protein kinases. Pkh proteins have been involved in several cellular functions, including cell wall integrity and endocytosis. However the global expression changes caused by their depletion are still unknown. RESULTS A doxycycline-repressible tetO7 promoter driving the expression of PKH2 in cells carrying deletions of the PKH1 and PKH3 genes allowed us to progressively deplete cells from Pkh proteins when treated with doxycycline. Global gene expression analysis indicate that depletion of Pkh results in the up-regulation of genes involved in the accumulation of glycogen and also of those related to stress responses. Moreover, genes involved in the ion transport were quickly down-regulated when the levels of Pkh decreased. The reduction in the mRNA levels required for protein translation, however, was only observed after longer doxycycline treatment (24 h). We uncovered that Pkh is important for the proper transcriptional response to heat shock, and is mostly required for the effects driven by the transcription factors Hsf1 and Msn2/Msn4, but is not required for down-regulation of the mRNA coding for ribosomal proteins. CONCLUSIONS By using the tetO7 promoter we elucidated for the first time the transcriptomic changes directly or indirectly caused by progressive depletion of Pkh. Furthermore, this system enabled the characterization of the transcriptional response triggered by heat shock in wild-type and Pkh-depleted cells, showing that about 40 % of the observed expression changes were, to some degree, dependent on Pkh.
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Affiliation(s)
- Daniel Pastor-Flores
- Research Group PhosphoSites, Medizinische Klinik I, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany. .,Present address: Division of Redox Regulation, German Cancer Research Center, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 280, 69120, Heidelberg, Germany.
| | - Jofre Ferrer-Dalmau
- Departament de Bioquímica i Biologia Molecular, Facultat de Veterinària, Universitat Autònoma de Barcelona, Cerdanyola 08193, Barcelona, Spain. .,Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola 08193, Barcelona, Spain.
| | - Anna Bahí
- Departament de Bioquímica i Biologia Molecular, Facultat de Veterinària, Universitat Autònoma de Barcelona, Cerdanyola 08193, Barcelona, Spain. .,Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola 08193, Barcelona, Spain.
| | - Martí Boleda
- Departament de Bioquímica i Biologia Molecular, Facultat de Veterinària, Universitat Autònoma de Barcelona, Cerdanyola 08193, Barcelona, Spain. .,Laboratoire d'Ecologie Alpine (LECA), UMR 5553, CNRS-Université Joseph Fourie, BP 53, 38041, Grenoble, France.
| | - Ricardo M Biondi
- Research Group PhosphoSites, Medizinische Klinik I, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
| | - Antonio Casamayor
- Departament de Bioquímica i Biologia Molecular, Facultat de Veterinària, Universitat Autònoma de Barcelona, Cerdanyola 08193, Barcelona, Spain. .,Institut de Biotecnologia i Biomedicina, Universitat Autònoma de Barcelona, Cerdanyola 08193, Barcelona, Spain.
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Eisosome Ultrastructure and Evolution in Fungi, Microalgae, and Lichens. EUKARYOTIC CELL 2015; 14:1017-42. [PMID: 26253157 DOI: 10.1128/ec.00106-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 07/30/2015] [Indexed: 01/01/2023]
Abstract
Eisosomes are among the few remaining eukaryotic cellular differentations that lack a defined function(s). These trough-shaped invaginations of the plasma membrane have largely been studied in Saccharomyces cerevisiae, in which their associated proteins, including two BAR domain proteins, have been identified, and homologues have been found throughout the fungal radiation. Using quick-freeze deep-etch electron microscopy to generate high-resolution replicas of membrane fracture faces without the use of chemical fixation, we report that eisosomes are also present in a subset of red and green microalgae as well as in the cysts of the ciliate Euplotes. Eisosome assembly is closely correlated with both the presence and the nature of cell walls. Microalgal eisosomes vary extensively in topology and internal organization. Unlike fungi, their convex fracture faces can carry lineage-specific arrays of intramembranous particles, and their concave fracture faces usually display fine striations, also seen in fungi, that are pitched at lineage-specific angles and, in some cases, adopt a broad-banded patterning. The conserved genes that encode fungal eisosome-associated proteins are not found in sequenced algal genomes, but we identified genes encoding two algal lineage-specific families of predicted BAR domain proteins, called Green-BAR and Red-BAR, that are candidate eisosome organizers. We propose a model for eisosome formation wherein (i) positively charged recognition patches first establish contact with target membrane regions and (ii) a (partial) unwinding of the coiled-coil conformation of the BAR domains then allows interactions between the hydrophobic faces of their amphipathic helices and the lipid phase of the inner membrane leaflet, generating the striated patterns.
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Evolutionarily conserved 5'-3' exoribonuclease Xrn1 accumulates at plasma membrane-associated eisosomes in post-diauxic yeast. PLoS One 2015; 10:e0122770. [PMID: 25811606 PMCID: PMC4374687 DOI: 10.1371/journal.pone.0122770] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 02/18/2015] [Indexed: 11/30/2022] Open
Abstract
Regulation of gene expression on the level of translation and mRNA turnover is widely conserved evolutionarily. We have found that the main mRNA decay enzyme, exoribonuclease Xrn1, accumulates at the plasma membrane-associated eisosomes after glucose exhaustion in a culture of the yeast S. cerevisiae. Eisosomal localization of Xrn1 is not achieved in cells lacking the main component of eisosomes, Pil1, or Sur7, the protein accumulating at the membrane compartment of Can1 (MCC) - the eisosome-organized plasma membrane microdomain. In contrast to the conditions of diauxic shift, when Xrn1 accumulates in processing bodies (P-bodies), or acute heat stress, in which these cytosolic accumulations of Xrn1 associate with eIF3a/Rpg1-containing stress granules, Xrn1 is not accompanied by other mRNA-decay machinery components when it accumulates at eisosomes in post-diauxic cells. It is important that Xrn1 is released from eisosomes after addition of fermentable substrate. We suggest that this spatial segregation of Xrn1 from the rest of the mRNA-decay machinery reflects a general regulatory mechanism, in which the key enzyme is kept separate from the rest of mRNA decay factors in resting cells but ready for immediate use when fermentable nutrients emerge and appropriate metabolism reprogramming is required. In particular, the localization of Xrn1 to the eisosome, together with previously published data, accents the relevance of this plasma membrane-associated compartment as a multipotent regulatory site.
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The yeast BDF1 regulates endocytosis via LSP1 under salt stress. Curr Microbiol 2015; 70:671-8. [PMID: 25572496 DOI: 10.1007/s00284-014-0773-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Accepted: 12/04/2014] [Indexed: 10/24/2022]
Abstract
Bromodomain-containing transcription factor, a kind of important regulating protein, can recognize and bind to acetylated histone. The homologous genes, BDF1 and BDF2, in Saccharomyces cerevisiae, respectively, encode a bromodomain-containing transcription factor. Previously study has demonstrated that both BDF1 and BDF2 participate in yeast salt stress response. Bdf1p deletion cells are sensitive to salt stress and this phenotype is suppressed by its homologue BDF2 in a dosage-dependent manner. In this study, we show that the histone deacetylase SIR2 over-expression enhanced dosage-dependent compensation of BDF2. SIR2 over-expression induced a global transcription change, and 1959 gene was down-regulated. We deleted some of the most significant down-regulated genes and did the spot assay. The results revealed that LSP1, an upstream component of endocytosis pathway, and CIN5, a transcription factor that mediates cellular resistance to stresses, can enhance salt resistance of bdf1∆. Further analysis demonstrated that under salt stress the endocytosis is over-activated in bdf1∆ but was recovered in bdf1∆ lsp1∆. To our best knowledge, this is the first report that the transcription factor Bdf1p regulates endocytosis under salt stress via LSP1, a major component of eisosomes that regulate the sites of endocytosis.
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Vaskovicova K, Stradalova V, Efenberk A, Opekarova M, Malinsky J. Assembly of fission yeast eisosomes in the plasma membrane of budding yeast: Import of foreign membrane microdomains. Eur J Cell Biol 2015; 94:1-11. [DOI: 10.1016/j.ejcb.2014.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Revised: 09/27/2014] [Accepted: 10/06/2014] [Indexed: 02/05/2023] Open
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