1
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Duewell BR, Faris KA, Hansen SD. Molecular basis of product recognition during PIP5K-mediated production of PI(4,5)P 2 with positive feedback. J Biol Chem 2024:107631. [PMID: 39098525 DOI: 10.1016/j.jbc.2024.107631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 07/20/2024] [Accepted: 07/26/2024] [Indexed: 08/06/2024] Open
Abstract
The ability for cells to localize and activate peripheral membrane binding proteins is critical for signal transduction. Ubiquitously important in these signaling processes are phosphatidylinositol phosphate (PIP) lipids, which are dynamically phosphorylated by PIP lipid kinases on intracellular membranes. Functioning primarily at the plasma membrane, phosphatidylinositol-4-phosphate 5-kinases (PIP5K) catalyzes the phosphorylation of PI(4)P to generate most of the PI(4,5)P2 lipids found in eukaryotic plasma membrane. Recently, we determined that PIP5K displays a positive feedback loop based on membrane-mediated dimerization and cooperative binding to its product, PI(4,5)P2. Here, we examine how two motifs contribute to PI(4,5)P2 recognition to control membrane association and catalysis of PIP5K. Using a combination of single molecule TIRF microscopy and kinetic analysis of PI(4)P lipid phosphorylation, we map the sequence of steps that allow PIP5K to cooperatively engage PI(4,5)P2. We find that the specificity loop regulates the rate of PIP5K membrane association and helps orient the kinase to more effectively bind PI(4,5)P2 lipids. After correctly orienting on the membrane, PIP5K transitions to binding PI(4,5)P2 lipids near the active site through a motif previously referred to as the substrate or PIP binding motif (PIPBM). The PIPBM has broad specificity for anionic lipids and serves a role in regulating membrane association in vitro and in vivo. Overall, our data supports a two-step membrane binding model where the specificity loop and PIPBM act in concert to help PIP5K orient and productively engage anionic lipids to drive the positive feedback during PI(4,5)P2 production.
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Affiliation(s)
- Benjamin R Duewell
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403; Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Katherine A Faris
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403; Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Scott D Hansen
- Department of Chemistry and Biochemistry, University of Oregon, Eugene, OR 97403; Institute of Molecular Biology, University of Oregon, Eugene, OR 97403.
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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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Yu Y, Chen D, Farmer SM, Xu S, Rios B, Solbach A, Ye X, Ye L, Zhang S. Endolysosomal trafficking controls yolk granule biogenesis in vitellogenic Drosophila oocytes. PLoS Genet 2024; 20:e1011152. [PMID: 38315726 PMCID: PMC10898735 DOI: 10.1371/journal.pgen.1011152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 02/27/2024] [Accepted: 01/22/2024] [Indexed: 02/07/2024] Open
Abstract
Endocytosis and endolysosomal trafficking are essential for almost all aspects of physiological functions of eukaryotic cells. As our understanding on these membrane trafficking events are mostly from studies in yeast and cultured mammalian cells, one challenge is to systematically evaluate the findings from these cell-based studies in multicellular organisms under physiological settings. One potentially valuable in vivo system to address this challenge is the vitellogenic oocyte in Drosophila, which undergoes extensive endocytosis by Yolkless (Yl), a low-density lipoprotein receptor (LDLR), to uptake extracellular lipoproteins into oocytes and package them into a specialized lysosome, the yolk granule, for storage and usage during later development. However, by now there is still a lack of sufficient understanding on the molecular and cellular processes that control yolk granule biogenesis. Here, by creating genome-tagging lines for Yl receptor and analyzing its distribution in vitellogenic oocytes, we observed a close association of different endosomal structures with distinct phosphoinositides and actin cytoskeleton dynamics. We further showed that Rab5 and Rab11, but surprisingly not Rab4 and Rab7, are essential for yolk granules biogenesis. Instead, we uncovered evidence for a potential role of Rab7 in actin regulation and observed a notable overlap of Rab4 and Rab7, two Rab GTPases that have long been proposed to have distinct spatial distribution and functional roles during endolysosomal trafficking. Through a small-scale RNA interference (RNAi) screen on a set of reported Rab5 effectors, we showed that yolk granule biogenesis largely follows the canonical endolysosomal trafficking and maturation processes. Further, the data suggest that the RAVE/V-ATPase complexes function upstream of or in parallel with Rab7, and are involved in earlier stages of endosomal trafficking events. Together, our study provides s novel insights into endolysosomal pathways and establishes vitellogenic oocyte in Drosophila as an excellent in vivo model for dissecting the highly complex membrane trafficking events in metazoan.
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Affiliation(s)
- Yue Yu
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
- Program in Neuroscience, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences (MD Anderson UTHealth GSBS), Houston, Texas, United States of America
| | - Dongsheng Chen
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
- The College of Life Sciences, Anhui Normal University, #1 Beijing East Road, Wuhu, Anhui, People’s Republic of China
| | - Stephen M. Farmer
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
- Program in Neuroscience, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences (MD Anderson UTHealth GSBS), Houston, Texas, United States of America
- Program in Biochemistry and Cell Biology, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences (MD Anderson UTHealth GSBS), Houston, Texas, United States of America
| | - Shiyu Xu
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
| | - Beatriz Rios
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
- Program in Neuroscience, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences (MD Anderson UTHealth GSBS), Houston, Texas, United States of America
| | - Amanda Solbach
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
- Program in Neuroscience, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences (MD Anderson UTHealth GSBS), Houston, Texas, United States of America
- Programs in Genetics and Epigenetics, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences (MD Anderson UTHealth GSBS), Houston, Texas, United States of America
| | - Xin Ye
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
| | - Lili Ye
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
| | - Sheng Zhang
- The Brown Foundation Institute of Molecular Medicine, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
- Program in Neuroscience, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences (MD Anderson UTHealth GSBS), Houston, Texas, United States of America
- Programs in Genetics and Epigenetics, The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences (MD Anderson UTHealth GSBS), Houston, Texas, United States of America
- Department of Neurobiology and Anatomy, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth), Houston, Texas, United States of America
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4
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Zhang T, Hale AT, Guo S, York JD. Coordinated inositide lipid-phosphatase activities of synaptojanin modulates actin cytoskeleton organization. Adv Biol Regul 2024; 91:101012. [PMID: 38220563 DOI: 10.1016/j.jbior.2023.101012] [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: 12/21/2023] [Accepted: 12/27/2023] [Indexed: 01/16/2024]
Abstract
Synaptojanin proteins are evolutionarily conserved regulators of vesicle transport and membrane homeostasis. Disruption of synaptojanin function has been implicated in a wide range of neurological disorders. Synaptojanins act as dual-functional lipid phosphatases capable of hydrolyzing a variety of phosphoinositides (PIPs) through autonomous SAC1-like PIP 4-phosphatase and PIP2 5-phosphatase domains. The rarity of an evolutionary configuration of tethering two distinct enzyme activities in a single protein prompted us to investigate their individual and combined roles in budding yeast. Both PIP and PIP2 phosphatase activities are encoded by multiple gene products and are independently essential for cell viability. In contrast, we observed that the synaptojanin proteins utilized both lipid-phosphatase activities to properly coordinate polarized distribution of actin during the cell cycle. Expression of each activity untethered (in trans) failed to properly reconstitute the basal actin regulatory activity; whereas tethering (in cis), even through synthetic linkers, was sufficient to complement these defects. Studies of chimeric proteins harboring PIP and PIP2 phosphatase domains from a variety of gene products indicate synaptojanin proteins have highly specialized activities and that the length of the linker between the lipid-phosphatase domains is critical for actin regulatory activity. Our data are consistent with synaptojanin possessing a strict requirement for both two-domain configuration for some but not all functions and provide mechanistic insights into a coordinated role of tethering distinct lipid-phosphatase activities.
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Affiliation(s)
- Tong Zhang
- Departments of Pharmacology and Cancer Biology, Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - Andrew T Hale
- Department of Biochemistry, Vanderbilt University, Nashville, TN, 37232, USA
| | - Shuling Guo
- Departments of Pharmacology and Cancer Biology, Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC, 27710, USA
| | - John D York
- Departments of Pharmacology and Cancer Biology, Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC, 27710, USA; Department of Biochemistry, Vanderbilt University, Nashville, TN, 37232, USA.
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5
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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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6
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Willet AH, Turner LA, Park JS, Ren L, Snider CE, Gould KL. Characterization of Pik1 function in fission yeast reveals its conserved role in lipid synthesis and not cytokinesis. J Cell Sci 2023; 136:jcs261415. [PMID: 37815455 PMCID: PMC10629694 DOI: 10.1242/jcs.261415] [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: 07/24/2023] [Accepted: 09/26/2023] [Indexed: 10/11/2023] Open
Abstract
Phosphatidylinositol (PI)-4-phosphate (PI4P) is a lipid found at the plasma membrane (PM) and Golgi in cells from yeast to humans. PI4P is generated from PI by PI4-kinases and can be converted into PI-4,5-bisphosphate [PI(4,5)P2]. Schizosaccharomyces pombe have two essential PI4-kinases - Stt4 and Pik1. Stt4 localizes to the PM, and its loss from the PM results in a decrease of PM PI4P and PI(4,5)P2. As a result, cells divide non-medially due to disrupted cytokinetic ring-PM anchoring. However, the localization and function of S. pombe Pik1 has not been thoroughly examined. Here, we found that Pik1 localizes exclusively to the trans-Golgi and is required for Golgi PI4P production. We determined that Ncs1 regulates Pik1, but unlike in other organisms, it is not required for Pik1 Golgi localization. When Pik1 function was disrupted, PM PI4P but not PI(4,5)P2 levels were reduced, a major difference compared with Stt4. We conclude that Stt4 is the chief enzyme responsible for producing the PI4P that generates PI(4,5)P2. Also, that cells with disrupted Pik1 do not divide asymmetrically highlights the specific importance of PM PI(4,5)P2 for cytokinetic ring-PM anchoring.
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Affiliation(s)
- Alaina H. Willet
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Lesley A. Turner
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Joshua S. Park
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Liping Ren
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Chloe E. Snider
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Kathleen L. Gould
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
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7
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Watson JL, Seinkmane E, Styles CT, Mihut A, Krüger LK, McNally KE, Planelles-Herrero VJ, Dudek M, McCall PM, Barbiero S, Vanden Oever M, Peak-Chew SY, Porebski BT, Zeng A, Rzechorzek NM, Wong DCS, Beale AD, Stangherlin A, Riggi M, Iwasa J, Morf J, Miliotis C, Guna A, Inglis AJ, Brugués J, Voorhees RM, Chambers JE, Meng QJ, O'Neill JS, Edgar RS, Derivery E. Macromolecular condensation buffers intracellular water potential. Nature 2023; 623:842-852. [PMID: 37853127 PMCID: PMC10665201 DOI: 10.1038/s41586-023-06626-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 09/08/2023] [Indexed: 10/20/2023]
Abstract
Optimum protein function and biochemical activity critically depends on water availability because solvent thermodynamics drive protein folding and macromolecular interactions1. Reciprocally, macromolecules restrict the movement of 'structured' water molecules within their hydration layers, reducing the available 'free' bulk solvent and therefore the total thermodynamic potential energy of water, or water potential. Here, within concentrated macromolecular solutions such as the cytosol, we found that modest changes in temperature greatly affect the water potential, and are counteracted by opposing changes in osmotic strength. This duality of temperature and osmotic strength enables simple manipulations of solvent thermodynamics to prevent cell death after extreme cold or heat shock. Physiologically, cells must sustain their activity against fluctuating temperature, pressure and osmotic strength, which impact water availability within seconds. Yet, established mechanisms of water homeostasis act over much slower timescales2,3; we therefore postulated the existence of a rapid compensatory response. We find that this function is performed by water potential-driven changes in macromolecular assembly, particularly biomolecular condensation of intrinsically disordered proteins. The formation and dissolution of biomolecular condensates liberates and captures free water, respectively, quickly counteracting thermal or osmotic perturbations of water potential, which is consequently robustly buffered in the cytoplasm. Our results indicate that biomolecular condensation constitutes an intrinsic biophysical feedback response that rapidly compensates for intracellular osmotic and thermal fluctuations. We suggest that preserving water availability within the concentrated cytosol is an overlooked evolutionary driver of protein (dis)order and function.
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Affiliation(s)
| | | | | | - Andrei Mihut
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | | | | | | | - Michal Dudek
- Wellcome Centre for Cell Matrix Research, University of Manchester, Manchester, UK
| | - Patrick M McCall
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | | | | | | | | | - Aiwei Zeng
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | | | | | | | - Alessandra Stangherlin
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Cluster of Excellence Cellular Stress Responses in Aging-associated Diseases (CECAD), Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Margot Riggi
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Janet Iwasa
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
| | - Jörg Morf
- Laboratory of Nuclear Dynamics, Babraham Institute, Cambridge, UK
| | | | - Alina Guna
- California Institute of Technology, Pasadena, CA, USA
| | | | - Jan Brugués
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | | | | | - Qing-Jun Meng
- Wellcome Centre for Cell Matrix Research, University of Manchester, Manchester, UK
| | | | - Rachel S Edgar
- Department of Infectious Disease, Imperial College London, London, UK.
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8
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Arabiotorre A, Bankaitis VA, Grabon A. Regulation of phosphoinositide metabolism in Apicomplexan parasites. Front Cell Dev Biol 2023; 11:1163574. [PMID: 37791074 PMCID: PMC10543664 DOI: 10.3389/fcell.2023.1163574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 07/11/2023] [Indexed: 10/05/2023] Open
Abstract
Phosphoinositides are a biologically essential class of phospholipids that contribute to organelle membrane identity, modulate membrane trafficking pathways, and are central components of major signal transduction pathways that operate on the cytosolic face of intracellular membranes in eukaryotes. Apicomplexans (such as Toxoplasma gondii and Plasmodium spp.) are obligate intracellular parasites that are important causative agents of disease in animals and humans. Recent advances in molecular and cell biology of Apicomplexan parasites reveal important roles for phosphoinositide signaling in key aspects of parasitosis. These include invasion of host cells, intracellular survival and replication, egress from host cells, and extracellular motility. As Apicomplexans have adapted to the organization of essential signaling pathways to accommodate their complex parasitic lifestyle, these organisms offer experimentally tractable systems for studying the evolution, conservation, and repurposing of phosphoinositide signaling. In this review, we describe the regulatory mechanisms that control the spatial and temporal regulation of phosphoinositides in the Apicomplexan parasites Plasmodium and T. gondii. We further discuss the similarities and differences presented by Apicomplexan phosphoinositide signaling relative to how these pathways are regulated in other eukaryotic organisms.
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Affiliation(s)
- Angela Arabiotorre
- Department of Cell Biology and Genetics, College of Medicine Texas A&M Health Sciences Center College Station, Bryan, TX, United States
| | - Vytas A. Bankaitis
- Department of Cell Biology and Genetics, College of Medicine Texas A&M Health Sciences Center College Station, Bryan, TX, United States
- Department of Biochemistry and Biophysics Texas A&M University College Station, College Station, TX, United States
- Department of Chemistry Texas A&M University College Station, College Station, TX, United States
| | - Aby Grabon
- Department of Cell Biology and Genetics, College of Medicine Texas A&M Health Sciences Center College Station, Bryan, TX, United States
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9
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Nenadic A, Zaman MF, Johansen J, Volpiana MW, Beh CT. Increased Phospholipid Flux Bypasses Overlapping Essential Requirements for the Yeast Sac1p Phosphoinositide Phosphatase and ER-PM Membrane Contact Sites. J Biol Chem 2023; 299:105092. [PMID: 37507017 PMCID: PMC10470028 DOI: 10.1016/j.jbc.2023.105092] [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: 08/21/2022] [Revised: 07/13/2023] [Accepted: 07/17/2023] [Indexed: 07/30/2023] Open
Abstract
In budding yeast cells, much of the inner surface of the plasma membrane (PM) is covered with the endoplasmic reticulum (ER). This association is mediated by seven ER membrane proteins that confer cortical ER-PM association at membrane contact sites (MCSs). Several of these membrane "tether" proteins are known to physically interact with the phosphoinositide phosphatase Sac1p. However, it is unclear how or if these interactions are necessary for their interdependent functions. We find that SAC1 inactivation in cells lacking the homologous synaptojanin-like genes INP52 and INP53 results in a significant increase in cortical ER-PM MCSs. We show in sac1Δ, sac1tsinp52Δ inp53Δ, or Δ-super-tether (Δ-s-tether) cells lacking all seven ER-PM tethering genes that phospholipid biosynthesis is disrupted and phosphoinositide distribution is altered. Furthermore, SAC1 deletion in Δ-s-tether cells results in lethality, indicating a functional overlap between SAC1 and ER-PM tethering genes. Transcriptomic profiling indicates that SAC1 inactivation in either Δ-s-tether or inp52Δ inp53Δ cells induces an ER membrane stress response and elicits phosphoinositide-dependent changes in expression of autophagy genes. In addition, by isolating high-copy suppressors that rescue sac1Δ Δ-s-tether lethality, we find that key phospholipid biosynthesis genes bypass the overlapping function of SAC1 and ER-PM tethers and that overexpression of the phosphatidylserine/phosphatidylinositol-4-phosphate transfer protein Osh6 also provides limited suppression. Combined with lipidomic analysis and determinations of intracellular phospholipid distributions, these results suggest that Sac1p and ER phospholipid flux controls lipid distribution to drive Osh6p-dependent phosphatidylserine/phosphatidylinositol-4-phosphate counter-exchange at ER-PM MCSs.
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Affiliation(s)
- Aleksa Nenadic
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Mohammad F Zaman
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Jesper Johansen
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Matthew W Volpiana
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Christopher T Beh
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada; Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, British Columbia, Canada.
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10
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Willet AH, Turner LA, Park JS, Ren L, Snider CE, Gould KL. Characterization of Pik1 function in fission yeast reveals its conserved role in lipid synthesis and not cytokinesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.24.550375. [PMID: 37546978 PMCID: PMC10402101 DOI: 10.1101/2023.07.24.550375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Phosphatidylinositol (PI)-4-phosphate (PI4P) is a lipid found at the plasma membrane (PM) and Golgi in cells from yeast to humans. PI4P is generated from PI by PI4-kinases and can be converted to PI-4,5-bisphosphate [PI(4,5)P 2 ]. Schizosaccharomyces pombe have 2 essential PI4-kinases: Stt4 and Pik1. Stt4 localizes to the PM and its loss from the PM results in a decrease of PM PI4P and PI(4,5)P 2 . As a result, cells divide non-medially due to disrupted cytokinetic ring-PM anchoring. However, the localization and function of S. pombe Pik1 has not been thoroughly examined. Here, we found that Pik1 localizes exclusively to the trans-Golgi and is required for Golgi PI4P production. We determined that Ncs1 regulates Pik1, but unlike in other organisms, it is not required for Pik1 Golgi localization. When Pik1 function was disrupted, PM PI4P but not PI(4,5)P 2 levels were reduced, a major difference with Stt4. We conclude that Stt4 is the chief enzyme responsible for producing the PI4P that generates PI(4,5)P 2 . Also, that cells with disrupted Pik1 do not divide asymmetrically highlights the specific importance of PM PI(4,5)P 2 for cytokinetic ring-PM anchoring. Summary statement Fission yeast Pik1 localizes exclusively to the trans-Golgi independently of Ncs1, where it contributes to PI4P but not PI(4,5)P 2 synthesis. Pik1 does not affect cytokinesis.
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11
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Benson A, McMurray M. Simultaneous co-overexpression of Saccharomyces cerevisiae septins Cdc3 and Cdc10 drives pervasive, phospholipid-, and tag-dependent plasma membrane localization. Cytoskeleton (Hoboken) 2023; 80:199-214. [PMID: 37098755 PMCID: PMC10524705 DOI: 10.1002/cm.21762] [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: 12/01/2022] [Revised: 03/29/2023] [Accepted: 04/17/2023] [Indexed: 04/27/2023]
Abstract
Septin proteins contribute to many eukaryotic processes involving cellular membranes. In the budding yeast Saccharomyces cerevisiae, septin hetero-oligomers interact with the plasma membrane (PM) almost exclusively at the future site of cytokinesis. While multiple mechanisms of membrane recruitment have been identified, including direct interactions with specific phospholipids and curvature-sensitive interactions via amphipathic helices, these do not fully explain why yeast septins do not localize all over the inner leaflet of the PM. While engineering an inducible split-yellow fluorescent protein (YFP) system to measure the kinetics of yeast septin complex assembly, we found that ectopic co-overexpression of two tagged septins, Cdc3 and Cdc10, resulted in nearly uniform PM localization, as well as perturbation of endogenous septin function. Septin localization and function in gametogenesis were also perturbed. PM localization required the C-terminal YFP fragment fused to the C terminus of Cdc3, the septin-associated kinases Cla4 and Gin4, and phosphotidylinositol-4,5-bis-phosphate (PI[4,5]P2 ), but not the putative PI(4,5)P2 -binding residues in Cdc3. Endogenous Cdc10 was recruited to the PM, likely contributing to the functional interference. PM-localized septins did not exchange with the cytosolic pool, indicative of stable polymers. These findings provide new clues as to what normally restricts septin localization to specific membranes.
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Affiliation(s)
- Aleyna Benson
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Michael McMurray
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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12
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Sukumar M, DeFlorio R, Pai CY, Stone DE. A member of the claudin superfamily influences formation of the front domain in pheromone-responding yeast cells. J Cell Sci 2023; 136:286256. [PMID: 36601911 DOI: 10.1242/jcs.260048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 12/19/2022] [Indexed: 01/06/2023] Open
Abstract
Cell polarization in response to chemical gradients is important in development and homeostasis across eukaryota. Chemosensing cells orient toward or away from gradient sources by polarizing along a front-rear axis. Using the mating response of budding yeast as a model of chemotropic cell polarization, we found that Dcv1, a member of the claudin superfamily, influences front-rear polarity. Although Dcv1 localized uniformly on the plasma membrane (PM) of vegetative cells, it was confined to the rear of cells responding to pheromone, away from the pheromone receptor. dcv1Δ conferred mislocalization of sensory, polarity and trafficking proteins, as well as PM lipids. These phenotypes correlated with defects in pheromone-gradient tracking and cell fusion. We propose that Dcv1 helps demarcate the mating-specific front domain primarily by restricting PM lipid distribution.
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Affiliation(s)
- Madhushalini Sukumar
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Reagan DeFlorio
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - Chih-Yu Pai
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
| | - David E Stone
- Department of Biological Sciences, University of Illinois at Chicago, Chicago, IL 60607, USA
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13
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Sulpizio A, Herpin L, Gingras R, Liu W, Bretscher A. Generation and characterization of conditional yeast mutants affecting each of the 2 essential functions of the scaffolding proteins Boi1/2 and Bem1. G3 (BETHESDA, MD.) 2022; 12:jkac273. [PMID: 36218417 PMCID: PMC9713459 DOI: 10.1093/g3journal/jkac273] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 09/23/2022] [Indexed: 02/17/2024]
Abstract
Boi1 and Boi2 are closely related yeast scaffolding proteins, either of which can perform an essential function. Previous studies have suggested a role in cell polarity, interacting with lipids, components of the late secretory pathway, and actin nucleators. We report detailed studies of their localization, dynamics, and the generation and characterization of conditional mutants. Boi1/2 are present on the plasma membrane in dynamic patches, then at the bud neck during cytokinesis. These distributions are unaffected by perturbation of the actin cytoskeleton or the secretory pathway. We identify 2 critical aromatic residues, present in both Boi1 and Boi2, in the essential C-terminal Pleckstrin-Homology domain, that cause temperature-sensitive growth resulting in defects in polarized growth leading to cell lysis. The scaffolding protein, Bem1, colocalizes with Boi1 in patches at the growing bud, and at the bud neck, the latter requiring the N-terminal SH3 domain of Boi1p. Loss of function of Boi1-SH3 domain renders Bem1 essential, which can be fully replaced by a fusion of the SH3b and PB1 domains of Bem1. Thus, the 2 essential functions of the Boi1/2/Bem1 proteins can be satisfied by Bem1-SH3b-PB1 and Boi1-Pleckstrin-Homology. Generation and characterization of conditional mutations in the essential function of Bem1 reveal a slow onset of defects in polarized growth, which is difficult to define a specific initial defect. This study provides more details into the functions of Boi1/2 and their relationship with Bem1 and presents the generation of conditional mutants that will be useful for future genetic analysis.
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Affiliation(s)
- Abigail Sulpizio
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Lancelot Herpin
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Robert Gingras
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
| | - Wenyu Liu
- BioAnalytical Sciences, Genentech Inc., South San Francisco, CA 94080, USA
| | - Anthony Bretscher
- Department of Molecular Biology and Genetics, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, USA
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14
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Nomura W, Ng SP, Takahara T, Maeda T, Kawada T, Goto T, Inoue Y. Roles of phosphatidylserine and phospholipase C in the activation of TOR complex 2 signaling in Saccharomyces cerevisiae. J Cell Sci 2022; 135:276172. [PMID: 35912799 DOI: 10.1242/jcs.259988] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 07/22/2022] [Indexed: 11/20/2022] Open
Abstract
The target of rapamycin (TOR) forms two distinct complexes, TORC1 and TORC2, to exert its functions essential for cellular growth and homeostasis. TORC1 signaling is regulated in response to nutrients such as amino acids and glucose; however, the mechanisms underlying the activation of TORC2 signaling are still poorly understood compared to TORC1 signaling. In the budding yeast Saccharomyces cerevisiae, TORC2 targets protein kinases Ypk1, Ypk2, and Pkc1 for phosphorylation. Plasma membrane stress is known to activate the TORC2-Ypk1/2 signaling. We have previously reported that methylglyoxal (MG), a metabolite derived from glycolysis, activates TORC2-Pkc1 signaling. In this study, we found that MG activates the TORC2-Ypk1/2 and TORC2-Pkc1 signaling, and that phosphatidylserine is involved in the activation of both signaling pathways. We also demonstrated that the Rho-family GTPase Cdc42 contributes to the plasma membrane stress-induced activation of TORC2-Ypk1/2 signaling. Furthermore, we revealed that phosphatidylinositol-specific phospholipase C, Plc1, contributes to the activation of both TORC2-Ypk1/2 and TORC2-Pkc1 signaling.
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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
| | - Su-Ping Ng
- Laboratory of Molecular Functions of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Terunao Takahara
- Department of Applied Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa-ku, Nagoya 464-8601, Japan
| | - Tatsuya Maeda
- Department of Biology, Hamamatsu University School of Medicine, Shizuoka, Japan
| | - Teruo Kawada
- Laboratory of Molecular Functions of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, Japan
| | - Tsuyoshi Goto
- Laboratory of Molecular Functions of Food, Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto 611-0011, 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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15
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Kozak M, Kaksonen M. Condensation of Ede1 promotes the initiation of endocytosis. eLife 2022; 11:72865. [PMID: 35412456 PMCID: PMC9064294 DOI: 10.7554/elife.72865] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 04/01/2022] [Indexed: 11/27/2022] Open
Abstract
Clathrin-mediated endocytosis is initiated by a network of weakly interacting proteins through a poorly understood mechanism. Ede1, the yeast homolog of mammalian Eps15, is an early-arriving endocytic protein and a key initiation factor. In the absence of Ede1, most other early endocytic proteins lose their punctate localization and endocytic uptake is decreased. We show that in yeast cells, cytosolic concentration of Ede1 is buffered at a critical level. Excess amounts of Ede1 form large condensates which recruit other endocytic proteins and exhibit properties of phase-separated liquid droplets. We demonstrate that the central region of Ede1, containing a coiled-coil and a prion-like region, is essential for both the condensate formation and the function of Ede1 in endocytosis. The functionality of Ede1 mutants lacking the central region can be partially rescued by an insertion of heterologous prion-like domains. Conversely, fusion of a heterologous lipid-binding domain with the central region of Ede1 can promote clustering into stable plasma membrane domains. We propose that the ability of Ede1 to form condensed networks supports the clustering of early endocytic proteins and promotes the initiation of endocytosis.
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Affiliation(s)
- Mateusz Kozak
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Marko Kaksonen
- Department of Biochemistry, University of Geneva, Geneva, Switzerland
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16
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Hwang R, Dang LH, Chen J, Lee JH, Marquer C. Triplication of Synaptojanin 1 in Alzheimer's Disease Pathology in Down Syndrome. Curr Alzheimer Res 2022; 19:795-807. [PMID: 36464875 DOI: 10.2174/1567205020666221202102832] [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: 08/13/2022] [Revised: 10/29/2022] [Accepted: 11/02/2022] [Indexed: 12/12/2022]
Abstract
Down Syndrome (DS), caused by triplication of human chromosome 21 (Hsa21) is the most common form of intellectual disability worldwide. Recent progress in healthcare has resulted in a dramatic increase in the lifespan of individuals with DS. Unfortunately, most will develop Alzheimer's disease like dementia (DS-AD) as they age. Understanding similarities and differences between DSAD and the other forms of the disease - i.e., late-onset AD (LOAD) and autosomal dominant AD (ADAD) - will provide important clues for the treatment of DS-AD. In addition to the APP gene that codes the precursor of the main component of amyloid plaques found in the brain of AD patients, other genes on Hsa21 are likely to contribute to disease initiation and progression. This review focuses on SYNJ1, coding the phosphoinositide phosphatase synaptojanin 1 (SYNJ1). First, we highlight the function of SYNJ1 in the brain. We then summarize the involvement of SYNJ1 in the different forms of AD at the genetic, transcriptomic, proteomic and neuropathology levels in humans. We further examine whether results in humans correlate with what has been described in murine and cellular models of the disease and report possible mechanistic links between SYNJ1 and the progression of the disease. Finally, we propose a set of questions that would further strengthen and clarify the role of SYNJ1 in the different forms of AD.
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Grants
- U19 AG068054, U01 AG051412, UL1TR001873, R01 AG058918, R01 AG058918 S1, P30AG10161, P30AG72975, R01AG15819, R01AG17917, R01AG03-6836, U01AG46152, U01AG61356, U01AG046139, P50 AG016574, R01 AG032990, U01AG046139, R01AG01-8023, U01AG006576, U01AG006786, R01AG025711, R01AG017216, R01AG003949, R01NS080820, U24NS07-2026, P30AG19610, U01AG046170, RF1AG057440, U24AG061340 NIH/NIA , National Institutes of Health
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Affiliation(s)
- Robert Hwang
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York City, NY, 10032, USA
| | - Lam-Ha Dang
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York City, NY, 10032, USA
- G.H. Sergievsky Center, Columbia University Medical Center, New York, NY 10032, USA
- Departments of Epidemiology and Neurology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Jacinda Chen
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York City, NY, 10032, USA
| | - Joseph H Lee
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York City, NY, 10032, USA
- G.H. Sergievsky Center, Columbia University Medical Center, New York, NY 10032, USA
- Departments of Epidemiology and Neurology, Columbia University Medical Center, New York, NY, 10032, USA
| | - Catherine Marquer
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York City, NY, 10032, USA
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York City, NY, 10032, USA
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17
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Laquel P, Testet E, Tuphile K, Cullin C, Fouillen L, Bessoule JJ, Doignon F. Phosphoinositides containing stearic acid are required for interaction between Rho GTPases and the exocyst to control the late steps of polarised exocytosis. Traffic 2021; 23:120-136. [PMID: 34908215 DOI: 10.1111/tra.12829] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 11/18/2021] [Accepted: 12/07/2021] [Indexed: 11/27/2022]
Abstract
Cell polarity is achieved by regulators such as small G proteins, exocyst members and phosphoinositides, with the latter playing a key role when bound to the exocyst proteins Sec3p and Exo70p, and Rho GTPases. This ensures asymmetric growth via the routing of proteins and lipids to the cell surface using actin cables. Previously, using a yeast mutant for a lysophosphatidylinositol acyl transferase encoded by the PSI1 gene, we demonstrated the role of stearic acid in the acyl chain of phosphoinositides in cytoskeletal organisation and secretion. Here, we use a genetic approach to characterise the effect on late steps of the secretory pathway. The constitutive overexpression of PSI1 in mutants affecting kinases involved in the phosphoinositide pathway demonstrated the role of molecular species containing stearic acid in bypassing a lack of phosphatidylinositol-4-phosphate PI(4)P at the plasma membrane, which is essential for the function of the Cdc42p module. Decreasing the levels of stearic acid-containing phosphoinositides modifies the environment of the actors involved in the control of late steps in the secretory pathway. This leads to decreased interactions between Exo70p and Sec3p, with Cdc42p, Rho1p and Rho3p, due to disruption of the GTP/GDP ratio of at least Rho1p and Rho3p GTPases, thereby preventing activation of the exocyst.
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Affiliation(s)
- P Laquel
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
| | - E Testet
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
| | - K Tuphile
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
| | - C Cullin
- Univ. Bordeaux, CNRS, Laboratoire de Chimie Biologie des Membranes & des Nano-objets, UMR 5248, Pessac, France
| | - L Fouillen
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France.,Metabolome Facility of Bordeaux, Functional Genomics Centre, F-33883 Villenave d'Ornon, France
| | - J J Bessoule
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
| | - F Doignon
- Univ. Bordeaux, CNRS, Laboratoire de Biogenèse Membranaire, UMR 5200, F-33140 Villenave d'Ornon, France
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18
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Robinson BP, Hawbaker S, Chiang A, Jordahl EM, Anaokar S, Nikiforov A, Bowman RW, Ziegler P, McAtee CK, Patton-Vogt J, O'Donnell AF. Alpha-arrestins Aly1/Art6 and Aly2/Art3 regulate trafficking of the glycerophosphoinositol transporter Git1 and impact phospholipid homeostasis. Biol Cell 2021; 114:3-31. [PMID: 34562280 DOI: 10.1111/boc.202100007] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/23/2021] [Accepted: 07/15/2021] [Indexed: 12/20/2022]
Abstract
BACKGROUND INFORMATION Phosphatidylinositol (PI) is an essential phospholipid, critical to membrane bilayers. The complete deacylation of PI by B-type phospholipases produces intracellular and extracellular glycerophosphoinositol (GPI). Extracellular GPI is transported into the cell via Git1, a member of the Major Facilitator Superfamily of transporters at the yeast plasma membrane. Internalized GPI is degraded to produce inositol, phosphate and glycerol, thereby contributing to these pools. GIT1 gene expression is controlled by nutrient balance, with phosphate or inositol starvation increasing GIT1 expression to stimulate GPI uptake. However, less is known about control of Git1 protein levels or localization. RESULTS We find that the α-arrestins, an important class of protein trafficking adaptor, regulate Git1 localization and this is dependent upon their interaction with the ubiquitin ligase Rsp5. Specifically, α-arrestin Aly2 stimulates Git1 trafficking to the vacuole under basal conditions, but in response to GPI-treatment, either Aly1 or Aly2 promote Git1 vacuole trafficking. Cell surface retention of Git1, as occurs in aly1∆ aly2∆ cells, is linked to impaired growth in the presence of exogenous GPI and results in increased uptake of radiolabeled GPI, suggesting that accumulation of GPI somehow causes cellular toxicity. Regulation of α-arrestin Aly1 by the protein phosphatase calcineurin improves steady-state and substrate-induced trafficking of Git1, however, calcineurin plays a larger role in Git1 trafficking beyond regulation of α-arrestins. Interestingly, loss of Aly1 and Aly2 increased phosphatidylinositol-3-phosphate on the limiting membrane of the vacuole, and this was further exacerbated by GPI addition, suggesting that the effect is partially linked to Git1. Loss of Aly1 and Aly2 leads to increased incorporation of inositol label from [3 H]-inositol-labelled GPI into PI, confirming that internalized GPI influences PI balance and indicating a role for the a-arrestins in this regulation. CONCLUSIONS The α-arrestins Aly1 and Aly2 are novel regulators of Git1 trafficking with previously unanticipated roles in controlling phospholipid distribution and balance. SIGNIFICANCE To our knowledge, this is the first example of α-arrestin regulation of phosphatidyliniositol-3-phosphate levels. In future studies it will be exciting to determine if other α-arrestins similarly alter PI and PIPs to change the cellular landscape.
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Affiliation(s)
- Benjamin P Robinson
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Sarah Hawbaker
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Annette Chiang
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Eric M Jordahl
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Sanket Anaokar
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Alexiy Nikiforov
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Ray W Bowman
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA.,Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Philip Ziegler
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Ceara K McAtee
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jana Patton-Vogt
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Allyson F O'Donnell
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA.,Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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19
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Malcova I, Bumba L, Uljanic F, Kuzmenko D, Nedomova J, Kamanova J. Lipid binding by the N-terminal motif mediates plasma membrane localization of Bordetella effector protein BteA. J Biol Chem 2021; 296:100607. [PMID: 33789161 PMCID: PMC8100071 DOI: 10.1016/j.jbc.2021.100607] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 03/24/2021] [Accepted: 03/26/2021] [Indexed: 11/23/2022] Open
Abstract
The respiratory pathogens Bordetella pertussis and Bordetella bronchiseptica employ a type III secretion system (T3SS) to inject a 69-kDa BteA effector protein into host cells. This effector is known to contain two functional domains, including an N-terminal lipid raft targeting (LRT) domain and a cytotoxic C-terminal domain that induces nonapoptotic and caspase-1–independent host cell death. However, the exact molecular mechanisms underlying the interaction of BteA with plasma membrane (PM) as well as its cytotoxic activity in the course of Bordetella infections remain poorly understood. Using a protein–lipid overlay assay and surface plasmon resonance, we show here that the recombinant LRT domain binds negatively charged membrane phospholipids. Specifically, we determined that the dissociation constants of the LRT domain–binding liposomes containing phosphatidylinositol 4,5-bisphosphate, phosphatidic acid, and phosphatidylserine were ∼450 nM, ∼490 nM, and ∼1.2 μM, respectively. Both phosphatidylserine and phosphatidylinositol 4,5-bisphosphate were required to target the LRT domain and/or full-length BteA to the PM of yeast cells. The membrane association further involved electrostatic and hydrophobic interactions of LRT and depended on a leucine residue in the L1 loop between the first two helices of the four-helix bundle. Importantly, charge-reversal substitutions within the L1 region disrupted PM localization of the BteA effector without hampering its cytotoxic activity during B. bronchiseptica infection of HeLa cells. The LRT-mediated targeting of BteA to the cytosolic leaflet of the PM of host cells is, therefore, dispensable for effector cytotoxicity.
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Affiliation(s)
- Ivana Malcova
- Laboratory of Infection Biology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Ladislav Bumba
- Laboratory of Molecular Biology of Bacterial Pathogens, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Filip Uljanic
- Laboratory of Infection Biology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Darya Kuzmenko
- Laboratory of Infection Biology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jana Nedomova
- Laboratory of Infection Biology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic
| | - Jana Kamanova
- Laboratory of Infection Biology, Institute of Microbiology of the Czech Academy of Sciences, Prague, Czech Republic.
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20
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Wang Y, Yuan P, Grabon A, Tripathi A, Lee D, Rodriguez M, Lönnfors M, Eisenberg-Bord M, Wang Z, Man Lam S, Schuldiner M, Bankaitis VA. Noncanonical regulation of phosphatidylserine metabolism by a Sec14-like protein and a lipid kinase. J Cell Biol 2021; 219:151686. [PMID: 32303746 PMCID: PMC7199851 DOI: 10.1083/jcb.201907128] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 12/20/2019] [Accepted: 02/10/2020] [Indexed: 01/20/2023] Open
Abstract
The yeast phosphatidylserine (PtdSer) decarboxylase Psd2 is proposed to engage in a membrane contact site (MCS) for PtdSer decarboxylation to phosphatidylethanolamine (PtdEtn). This proposed MCS harbors Psd2, the Sec14-like phosphatidylinositol transfer protein (PITP) Sfh4, the Stt4 phosphatidylinositol (PtdIns) 4-OH kinase, the Scs2 tether, and an uncharacterized protein. We report that, of these components, only Sfh4 and Stt4 regulate Psd2 activity in vivo. They do so via distinct mechanisms. Sfh4 operates via a mechanism for which its PtdIns-transfer activity is dispensable but requires an Sfh4-Psd2 physical interaction. The other requires Stt4-mediated production of PtdIns-4-phosphate (PtdIns4P), where Stt4 (along with the Sac1 PtdIns4P phosphatase and endoplasmic reticulum–plasma membrane tethers) indirectly modulate Psd2 activity via a PtdIns4P homeostatic mechanism that influences PtdSer accessibility to Psd2. These results identify an example in which the biological function of a Sec14-like PITP is cleanly uncoupled from its canonical in vitro PtdIns-transfer activity and challenge popular functional assumptions regarding lipid-transfer protein involvements in MCS function.
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Affiliation(s)
- Yaxi Wang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX.,Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX
| | - Peihua Yuan
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX
| | - Aby Grabon
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX
| | - Ashutosh Tripathi
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX
| | - Dongju Lee
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX
| | - Martin Rodriguez
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX
| | - Max Lönnfors
- Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX
| | | | - Zehua Wang
- University of Chinese Academy of Sciences, Beijing, China.,State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Sin Man Lam
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Maya Schuldiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Vytas A Bankaitis
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX.,Department of Molecular & Cellular Medicine, Texas A&M Health Science Center, College Station, TX.,Department of Chemistry, Texas A&M University, College Station, TX
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21
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Laha D, Kamleitner M, Johnen P, Schaaf G. Analyses of Inositol Phosphates and Phosphoinositides by Strong Anion Exchange (SAX)-HPLC. Methods Mol Biol 2021; 2295:365-378. [PMID: 34047987 DOI: 10.1007/978-1-0716-1362-7_20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The phosphate esters of myo-inositol (Ins) occur ubiquitously in biology. These molecules exist as soluble or membrane-resident derivatives and regulate a plethora of cellular functions including phosphate homeostasis, DNA repair, vesicle trafficking, metabolism, cell polarity, tip-directed growth, and membrane morphogenesis. Phosphorylation of all inositol hydroxyl groups generates phytic acid (InsP6), the most abundant inositol phosphate present in eukaryotic cells. However, phytic acid is not the most highly phosphorylated naturally occurring inositol phosphate. Specialized small molecule kinases catalyze the formation of the so-called myo-inositol pyrophosphates (PP-InsPs), such as InsP7 and InsP8. These molecules are characterized by one or several "high-energy" diphosphate moieties and are ubiquitous in eukaryotic cells. In plants, PP-InsPs play critical roles in immune responses and nutrient sensing. The detection of inositol derivatives in plants is challenging. This is particularly the case for inositol pyrophosphates because diphospho bonds are labile in plant cell extracts due to high amounts of acid phosphatase activity. We present two steady-state inositol labeling-based techniques coupled with strong anion exchange (SAX)-HPLC analyses that allow robust detection and quantification of soluble and membrane-resident inositol polyphosphates in plant extracts. These techniques will be instrumental to uncover the cellular and physiological processes controlled by these intriguing regulatory molecules in plants.
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Affiliation(s)
- Debabrata Laha
- Department of Biochemistry, Indian Institute of Science, Bangalore, India
| | - Marília Kamleitner
- Department of Plant Nutrition, Institute of Crop Science and Resource Conservation, Rheinische Friedrich-Wilhelms-University Bonn, Bonn, Germany
| | - Philipp Johnen
- Department of Plant Nutrition, Institute of Crop Science and Resource Conservation, Rheinische Friedrich-Wilhelms-University Bonn, Bonn, Germany.,BASF SE, Limburgerhof, Germany
| | - Gabriel Schaaf
- Department of Plant Nutrition, Institute of Crop Science and Resource Conservation, Rheinische Friedrich-Wilhelms-University Bonn, Bonn, Germany.
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22
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Basu S, González B, Li B, Kimble G, Kozminski KG, Cullen PJ. Functions for Cdc42p BEM adaptors in regulating a differentiation-type MAP kinase pathway. Mol Biol Cell 2020; 31:491-510. [PMID: 31940256 PMCID: PMC7185891 DOI: 10.1091/mbc.e19-08-0441] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Ras homology (Rho) GTPases regulate cell polarity and signal transduction pathways to control morphogenetic responses in different settings. In yeast, the Rho GTPase Cdc42p regulates cell polarity, and through the p21-activated kinase Ste20p, Cdc42p also regulates mitogen-activated protein kinase (MAPK) pathways (mating, filamentous growth or fMAPK, and HOG). Although much is known about how Cdc42p regulates cell polarity and the mating pathway, how Cdc42p regulates the fMAPK pathway is not clear. To address this question, Cdc42p-dependent MAPK pathways were compared in the filamentous (Σ1278b) strain background. Each MAPK pathway showed a unique activation profile, with the fMAPK pathway exhibiting slow activation kinetics compared with the mating and HOG pathways. A previously characterized version of Cdc42p, Cdc42pE100A, that is specifically defective for fMAPK pathway signaling, was defective for interaction with Bem4p, the pathway-specific adaptor for the fMAPK pathway. Corresponding residues in Bem4p were identified that were required for interaction with Cdc42p and fMAPK pathway signaling. The polarity adaptor Bem1p also regulated the fMAPK pathway. Versions of Bem1p defective for recruitment of Ste20p to the plasma membrane, intramolecular interactions, and interaction with the GEF, Cdc24p, were defective for fMAPK pathway signaling. Bem1p also regulated effector pathways in different ways. In some pathways, multiple domains of the protein were required for its function, whereas in other pathways, a single domain or function was needed. Genetic suppression tests showed that Bem4p and Bem1p regulate the fMAPK pathway in an ordered sequence. Collectively, the study demonstrates unique and sequential functions for Rho GTPase adaptors in regulating MAPK pathways.
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Affiliation(s)
- Sukanya Basu
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260
| | - Beatriz González
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260
| | - Boyang Li
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260
| | - Garrett Kimble
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260
| | - Keith G Kozminski
- Departments of Biology and Cell Biology, University of Virginia, Charlottesville, VA 22904
| | - Paul J Cullen
- Department of Biological Sciences, University at Buffalo, Buffalo, NY 14260
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23
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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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Lau N, Haeberle AL, O’Keeffe BJ, Latomanski EA, Celli J, Newton HJ, Knodler LA. SopF, a phosphoinositide binding effector, promotes the stability of the nascent Salmonella-containing vacuole. PLoS Pathog 2019; 15:e1007959. [PMID: 31339948 PMCID: PMC6682159 DOI: 10.1371/journal.ppat.1007959] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2019] [Revised: 08/05/2019] [Accepted: 07/02/2019] [Indexed: 12/19/2022] Open
Abstract
The enteric bacterial pathogen Salmonella enterica serovar Typhimurium (S. Typhimurium), utilizes two type III secretion systems (T3SSs) to invade host cells, survive and replicate intracellularly. T3SS1 and its dedicated effector proteins are required for bacterial entry into non-phagocytic cells and establishment and trafficking of the nascent Salmonella-containing vacuole (SCV). Here we identify the first T3SS1 effector required to maintain the integrity of the nascent SCV as SopF. SopF associates with host cell membranes, either when translocated by bacteria or ectopically expressed. Recombinant SopF binds to multiple phosphoinositides in protein-lipid overlays, suggesting that it targets eukaryotic cell membranes via phospholipid interactions. In yeast, the subcellular localization of SopF is dependent on the activity of Mss4, a phosphatidylinositol 4-phosphate 5-kinase that generates PI(4,5)P2 from PI(4)P, indicating that membrane recruitment of SopF requires specific phospholipids. Ectopically expressed SopF partially colocalizes with specific phosphoinositide pools present on the plasma membrane in mammalian cells and with cytoskeletal-associated markers at the leading edge of cells. Translocated SopF concentrates on plasma membrane ruffles and around intracellular bacteria, presumably on the SCV. SopF is not required for bacterial invasion of non-phagocytic cells but is required for maintenance of the internalization vacuole membrane as infection with a S. Typhimurium ΔsopF mutant led to increased lysis of the SCV compared to wild type bacteria. Our structure-function analysis shows that the carboxy-terminal seven amino acids of SopF are essential for its membrane association in host cells and to promote SCV membrane stability. We also describe that SopF and another T3SS1 effector, SopB, act antagonistically to modulate nascent SCV membrane dynamics. In summary, our study highlights that a delicate balance of type III effector activities regulates the stability of the Salmonella internalization vacuole.
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Affiliation(s)
- Nicole Lau
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
| | - Amanda L. Haeberle
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
| | - Brittany J. O’Keeffe
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
| | - Eleanor A. Latomanski
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
| | - Jean Celli
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
| | - Hayley J. Newton
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- * E-mail: (LAK); (HJN)
| | - Leigh A. Knodler
- The Department of Microbiology and Immunology at the Peter Doherty Institute for Infection and Immunity, University of Melbourne, Melbourne, Victoria, Australia
- Paul G. Allen School for Global Animal Health, College of Veterinary Medicine, Washington State University, Pullman, WA, United States of America
- * E-mail: (LAK); (HJN)
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25
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Lev S, Li C, Desmarini D, Sorrell TC, Saiardi A, Djordjevic JT. Fungal Kinases With a Sweet Tooth: Pleiotropic Roles of Their Phosphorylated Inositol Sugar Products in the Pathogenicity of Cryptococcus neoformans Present Novel Drug Targeting Opportunities. Front Cell Infect Microbiol 2019; 9:248. [PMID: 31380293 PMCID: PMC6660261 DOI: 10.3389/fcimb.2019.00248] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 06/26/2019] [Indexed: 12/17/2022] Open
Abstract
Invasive fungal pathogens cause more than 300 million serious human infections and 1.6 million deaths per year. A clearer understanding of the mechanisms by which these fungi cause disease is needed to identify novel targets for urgently needed therapies. Kinases are key components of the signaling and metabolic circuitry of eukaryotic cells, which include fungi, and kinase inhibition is currently being exploited for the treatment of human diseases. Inhibiting evolutionarily divergent kinases in fungal pathogens is a promising avenue for antifungal drug development. One such group of kinases is the phospholipase C1-dependent inositol polyphosphate kinases (IPKs), which act sequentially to transfer a phosphoryl group to a pre-phosphorylated inositol sugar (IP). This review focuses on the roles of fungal IPKs and their IP products in fungal pathogenicity, as determined predominantly from studies performed in the model fungal pathogen Cryptococcus neoformans, and compares them to what is known in non-pathogenic model fungi and mammalian cells to highlight potential drug targeting opportunities.
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Affiliation(s)
- Sophie Lev
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Cecilia Li
- Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Centre for Infectious Diseases and Microbiology-Public Health, NSW Health Pathology, Westmead Hospital, Sydney, NSW, Australia
| | - Desmarini Desmarini
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Tania C Sorrell
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
| | - Adolfo Saiardi
- MRC Laboratory for Molecular Cell Biology, University College London, London, United Kingdom
| | - Julianne T Djordjevic
- Centre for Infectious Diseases and Microbiology, The Westmead Institute for Medical Research, Sydney, NSW, Australia.,Sydney Medical School-Westmead, The University of Sydney, Sydney, NSW, Australia.,Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW, Australia
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26
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Martinez Marshall MN, Emmerstorfer-Augustin A, Leskoske KL, Zhang LH, Li B, Thorner J. Analysis of the roles of phosphatidylinositol-4,5- bisphosphate and individual subunits in assembly, localization, and function of Saccharomyces cerevisiae target of rapamycin complex 2. Mol Biol Cell 2019; 30:1555-1574. [PMID: 30969890 PMCID: PMC6724684 DOI: 10.1091/mbc.e18-10-0682] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Eukaryotic cell survival requires maintenance of plasma membrane (PM) homeostasis in response to environmental insults and changes in lipid metabolism. In yeast, a key regulator of PM homeostasis is target of rapamycin (TOR) complex 2 (TORC2), a multiprotein complex containing the evolutionarily conserved TOR protein kinase isoform Tor2. PM localization is essential for TORC2 function. One core TORC2 subunit (Avo1) and two TORC2-associated regulators (Slm1 and Slm2) contain pleckstrin homology (PH) domains that exhibit specificity for binding phosphatidylinositol-4,5-bisphosphate (PtdIns4,5P2). To investigate the roles of PtdIns4,5P2 and constituent subunits of TORC2, we used auxin-inducible degradation to systematically eliminate these factors and then examined localization, association, and function of the remaining TORC2 components. We found that PtdIns4,5P2 depletion significantly reduced TORC2 activity, yet did not prevent PM localization or disassembly of TORC2. Moreover, truncated Avo1 (lacking its C-terminal PH domain) was still recruited to the PM and supported growth. Even when all three PH-containing proteins were absent, the remaining TORC2 subunits were PM-bound. Revealingly, Avo3 localized to the PM independent of both Avo1 and Tor2, whereas both Tor2 and Avo1 required Avo3 for their PM anchoring. Our findings provide new mechanistic information about TORC2 and pinpoint Avo3 as pivotal for TORC2 PM localization and assembly in vivo.
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Affiliation(s)
- Maria Nieves Martinez Marshall
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Anita Emmerstorfer-Augustin
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Kristin L Leskoske
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Lydia H Zhang
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Biyun Li
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
| | - Jeremy Thorner
- Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720
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27
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Chandra M, Chin YKY, Mas C, Feathers JR, Paul B, Datta S, Chen KE, Jia X, Yang Z, Norwood SJ, Mohanty B, Bugarcic A, Teasdale RD, Henne WM, Mobli M, Collins BM. Classification of the human phox homology (PX) domains based on their phosphoinositide binding specificities. Nat Commun 2019; 10:1528. [PMID: 30948714 PMCID: PMC6449406 DOI: 10.1038/s41467-019-09355-y] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 02/21/2019] [Indexed: 01/05/2023] Open
Abstract
Phox homology (PX) domains are membrane interacting domains that bind to phosphatidylinositol phospholipids or phosphoinositides, markers of organelle identity in the endocytic system. Although many PX domains bind the canonical endosome-enriched lipid PtdIns3P, others interact with alternative phosphoinositides, and a precise understanding of how these specificities arise has remained elusive. Here we systematically screen all human PX domains for their phospholipid preferences using liposome binding assays, biolayer interferometry and isothermal titration calorimetry. These analyses define four distinct classes of human PX domains that either bind specifically to PtdIns3P, non-specifically to various di- and tri-phosphorylated phosphoinositides, bind both PtdIns3P and other phosphoinositides, or associate with none of the lipids tested. A comprehensive evaluation of PX domain structures reveals two distinct binding sites that explain these specificities, providing a basis for defining and predicting the functional membrane interactions of the entire PX domain protein family.
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Affiliation(s)
- Mintu Chandra
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Yanni K-Y Chin
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Caroline Mas
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, 4072, Australia
- Integrated Structural Biology Grenoble, Grenoble, France
| | - J Ryan Feathers
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Blessy Paul
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Sanchari Datta
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Kai-En Chen
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Xinying Jia
- Centre for Advanced Imaging and School of Chemistry and Molecular Biology, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Zhe Yang
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Suzanne J Norwood
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Biswaranjan Mohanty
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, Monash University, 381 Royal Parade, Parkville, 3052, VIC, Australia
| | - Andrea Bugarcic
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Rohan D Teasdale
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, 4072, Australia
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - W Mike Henne
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Mehdi Mobli
- Centre for Advanced Imaging and School of Chemistry and Molecular Biology, The University of Queensland, St. Lucia, QLD, 4072, Australia
| | - Brett M Collins
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, QLD, 4072, Australia.
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28
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Meca J, Massoni-Laporte A, Martinez D, Sartorel E, Loquet A, Habenstein B, McCusker D. Avidity-driven polarity establishment via multivalent lipid-GTPase module interactions. EMBO J 2018; 38:embj.201899652. [PMID: 30559330 DOI: 10.15252/embj.201899652] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 10/26/2018] [Accepted: 11/02/2018] [Indexed: 12/17/2022] Open
Abstract
While Rho GTPases are indispensible regulators of cellular polarity, the mechanisms underlying their anisotropic activation at membranes have been elusive. Using the budding yeast Cdc42 GTPase module, which includes a guanine nucleotide exchange factor (GEF) Cdc24 and the scaffold Bem1, we find that avidity generated via multivalent anionic lipid interactions is a critical mechanistic constituent of polarity establishment. We identify basic cluster (BC) motifs in Bem1 that drive the interaction of the scaffold-GEF complex with anionic lipids at the cell pole. This interaction appears to influence lipid acyl chain ordering, thus regulating membrane rigidity and feedback between Cdc42 and the membrane environment. Sequential mutation of the Bem1 BC motifs, PX domain, and the PH domain of Cdc24 lead to a progressive loss of cellular polarity stemming from defective Cdc42 nanoclustering on the plasma membrane and perturbed signaling. Our work demonstrates the importance of avidity via multivalent anionic lipid interactions in the spatial control of GTPase activation.
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Affiliation(s)
- Julien Meca
- CNRS, UMR 5095, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
| | - Aurélie Massoni-Laporte
- CNRS, UMR 5095, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
| | - Denis Martinez
- CNRS, UMR 5248, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
| | - Elodie Sartorel
- CNRS, UMR 5095, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
| | - Antoine Loquet
- CNRS, UMR 5248, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
| | - Birgit Habenstein
- CNRS, UMR 5248, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
| | - Derek McCusker
- CNRS, UMR 5095, European Institute of Chemistry and Biology, University of Bordeaux, Pessac, France
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29
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Coronas-Serna JM, Fernández-Acero T, Molina M, Cid VJ. A humanized yeast-based toolkit for monitoring phosphatidylinositol 3-kinase activity at both single cell and population levels. ACTA ACUST UNITED AC 2018; 5:545-554. [PMID: 30533419 PMCID: PMC6282018 DOI: 10.15698/mic2018.12.660] [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] [Indexed: 11/13/2022]
Abstract
Phosphatidylinositol 3-kinase (PI3K) is a key regulator of phosphoinositide-dependent signaling in mammalian cells and its dysfunction is related to multiple syndromes, including cancer. By heterologous expression in Saccharomyces cerevisiae, we have developed a humanized yeast system as a tool for functional studies on higher eukaryotic PI3K. Here we restrict PI3K activity in yeast to specific plasma membrane (PM) microdomains by fusing the p110α PI3K catalytic subunit to either a septin or an eisosome component. We engineered a Dual Reporter for PI3K (DRAPIK), useful to monitor activity on cellular membranes in vivo at a single-cell level, by simultaneous PM staining of the enzyme substrate (PtdIns4,5P2) with GFP and its product (PtdIns3,4,5P3) with mCherry. We also developed a sensitive FLUorescence by PI3K Inhibition (FLUPI) assay based on a GFP transcriptional reporter that is turned off by PI3K activity. This reporter system proved useful to monitor PI3K inhibition in vivo by active compounds. Such novel tools were used to study the performance of yeast PM microdomain-directed PI3K. Our results show that tethering heterologous PI3K to discrete PM domains potentiates its activity on PtdIns4,5P2 but different locations display distinct effects on yeast growth and endocytosis.
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Affiliation(s)
- Julia María Coronas-Serna
- Departamento de Microbiología y Parasitología, Facultad de Farmacia. Universidad Complutense de Madrid e Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS)
| | - Teresa Fernández-Acero
- Departamento de Microbiología y Parasitología, Facultad de Farmacia. Universidad Complutense de Madrid e Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS)
| | - María Molina
- Departamento de Microbiología y Parasitología, Facultad de Farmacia. Universidad Complutense de Madrid e Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS)
| | - Víctor J Cid
- Departamento de Microbiología y Parasitología, Facultad de Farmacia. Universidad Complutense de Madrid e Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS)
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30
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Decrease in plasma membrane tension triggers PtdIns(4,5)P 2 phase separation to inactivate TORC2. Nat Cell Biol 2018; 20:1043-1051. [PMID: 30154550 PMCID: PMC6237274 DOI: 10.1038/s41556-018-0150-z] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 06/21/2018] [Indexed: 02/06/2023]
Abstract
The target of rapamycin complex 2 (TORC2) plays a key role in maintaining the homeostasis of plasma membrane (PM) tension. TORC2 activation following increased PM tension involves redistribution of the Slm1 and 2 paralogues from PM invaginations known as eisosomes into membrane compartments containing TORC2. How Slm1/2 relocalization is triggered, and if/how this plays a role in TORC2 inactivation with decreased PM tension, is unknown. Using osmotic shocks and palmitoylcarnitine as orthogonal tools to manipulate PM tension, we demonstrate that decreased PM tension triggers spontaneous, energy-independent reorganization of pre-existing phosphatidylinositol-4,5-bisphosphate into discrete invaginated membrane domains, which cluster and inactivate TORC2. These results demonstrate that increased and decreased membrane tension are sensed through different mechanisms, highlighting a role for membrane lipid phase separation in mechanotransduction.
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31
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Live-cell imaging of early coat protein dynamics during clathrin-mediated endocytosis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1566-1578. [PMID: 30077636 DOI: 10.1016/j.bbamcr.2018.07.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 06/23/2018] [Accepted: 07/25/2018] [Indexed: 12/30/2022]
Abstract
Clathrin-mediated endocytosis is an essential process that is mediated by the stepwise appearance or disappearance of many different proteins at the plasma membrane. In the budding yeast, these proteins are categorized into at least five modules, according to their spatiotemporal dynamics. Among them, the dynamics of proteins in the late coat module are well characterized, but those in the early coat module still remain unclear because of the lack of a suitable fluorescent marker with sufficient brightness to allow analysis. To examine the dynamics of early coat proteins, in this study we tagged four representative early coat proteins with 3GFP, and expressed them in a single cell. This cell exhibited a significant increase in the fluorescence intensity of early coat proteins relative to that of each 3GFP-tagged protein. Using this strain, we performed a detailed analysis of early coat proteins, including their precise lifetime, changes in fluorescence intensity, and motility on the plasma membrane. We found that early coat proteins move on the plasma membrane before internalization. Additionally, we expressed these 3GFP-tagged proteins in mutants with deletion of genes related to endocytosis, and found four mutants - end3Δ, las17Δ, sla2Δ, and clc1Δ- in which the lifetime of early coat proteins was markedly increased. Interestingly, deletion of the CLC1 gene dramatically reduced the internalization of early coat proteins whereas internalization of actin patches was largely unchanged, suggesting that the clc1Δ mutant might have a defect in the link between the early coat and actin modules.
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32
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Bean BDM, Dziurdzik SK, Kolehmainen KL, Fowler CMS, Kwong WK, Grad LI, Davey M, Schluter C, Conibear E. Competitive organelle-specific adaptors recruit Vps13 to membrane contact sites. J Cell Biol 2018; 217:3593-3607. [PMID: 30018089 PMCID: PMC6168272 DOI: 10.1083/jcb.201804111] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/13/2018] [Accepted: 07/02/2018] [Indexed: 01/24/2023] Open
Abstract
Targeting of Vps13 to membranes is highly dynamic. Bean et al. identify Ypt35 and Mcp1 as adaptors for Vps13 at endosomes and mitochondria, respectively, and show all known Vps13 adaptors use a related motif to compete for Vps13 membrane recruitment. The regulated expansion of membrane contact sites, which mediate the nonvesicular exchange of lipids between organelles, requires the recruitment of additional contact site proteins. Yeast Vps13 dynamically localizes to membrane contacts that connect the ER, mitochondria, endosomes, and vacuoles and is recruited to the prospore membrane in meiosis, but its targeting mechanism is unclear. In this study, we identify the sorting nexin Ypt35 as a novel adaptor that recruits Vps13 to endosomal and vacuolar membranes. We characterize an interaction motif in the Ypt35 N terminus and identify related motifs in the prospore membrane adaptor Spo71 and the mitochondrial membrane protein Mcp1. We find that Mcp1 is a mitochondrial adaptor for Vps13, and the Vps13–Mcp1 interaction, but not Ypt35, is required when ER-mitochondria contacts are lost. All three adaptors compete for binding to a conserved six-repeat region of Vps13 implicated in human disease. Our results support a competition-based model for regulating Vps13 localization at cellular membranes.
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Affiliation(s)
- Björn D M Bean
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Samantha K Dziurdzik
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Kathleen L Kolehmainen
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada.,Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Claire M S Fowler
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Waldan K Kwong
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Leslie I Grad
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada.,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Michael Davey
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Cayetana Schluter
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada
| | - Elizabeth Conibear
- Centre for Molecular Medicine and Therapeutics, British Columbia Children's Hospital Research Institute, University of British Columbia, Vancouver, Canada .,Department of Medical Genetics, University of British Columbia, Vancouver, Canada
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33
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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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34
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Woodman S, Trousdale C, Conover J, Kim K. Yeast membrane lipid imbalance leads to trafficking defects toward the Golgi. Cell Biol Int 2018; 42:890-902. [PMID: 29500884 DOI: 10.1002/cbin.10956] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 02/24/2018] [Indexed: 12/19/2022]
Abstract
Protein recycling is an essential cellular process involving endocytosis, intracellular trafficking, and exocytosis. In mammalian systems membrane lipids, including cholesterol, sphingolipids, and phospholipids, play a pivotal role in protein recycling. To address this role in budding yeast, Saccharomyces cerevisiae, we utilized GFP-Snc1, a v-SNARE protein serving as a fluorescent marker for faithfully reporting the recycling pathway. Here we demonstrate results that display moderate to significant GFP-Snc1 recycling defects upon overexpression or inactivation of phospholipid, ergosterol, and sphingolipid biosynthesis enzymes, indicating that the homeostasis of membrane lipid levels is prerequisite for proper protein recycling. By using a truncated version of GFP-Snc1 that cannot be recycled from the plasma membrane, we determined that abnormalities in Snc1 localization in membrane lipid overexpression or underexpression mutants are not due to defects in the synthetic/secretory pathway, but rather in the intracellular trafficking pathway. We found that membrane lipid imbalance resulted in an accumulation of the late endosome marker Vps10-GFP, indicating trafficking from the endosomes to the Golgi may be being hindered, preventing recycling to the plasma membrane. To elucidate the possible mechanism for this trafficking hindrance, we stained the actin cytoskeleton, then quantified the percentage of cells with visible actin cables. Compared to wild-type cells, membrane lipid mutant cells exhibited lower levels of actin cables, indicating the actin cytoskeleton is disrupted upon membrane lipid imbalance. Taken together, our results show that impairment of proper recycling may be due to disruption of the actin cytoskeleton, which causes trafficking hindrance between the endosomes and Golgi.
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Affiliation(s)
- Sara Woodman
- Missouri State University, 901 S National Ave., Springfield, Missouri
| | - Christopher Trousdale
- Missouri State University, 901 S National Ave., Springfield, Missouri.,Washington University in St. Louis, 1 Brookings Dr., St. Louis, Missouri
| | - Justin Conover
- Missouri State University, 901 S National Ave., Springfield, Missouri.,Iowa State University, Ames, Iowa
| | - Kyoungtae Kim
- Missouri State University, 901 S National Ave., Springfield, Missouri.,Iowa State University, Ames, Iowa
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35
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Abstract
Recently, a new form of autosomal recessive early-onset parkinsonism (PARK20), due to mutations in the gene encoding the phosphoinositide phosphatase, Synaptojanin 1 (Synj1), has been reported. Several genes responsible for hereditary forms of Parkinson’s disease are implicated in distinct steps of the endolysosomal pathway. However, the nature and the degree of endocytic membrane trafficking impairment in early-onset parkinsonism remains elusive. Here, we show that depletion of Synj1 causes drastic alterations of early endosomes, which become enlarged and more numerous, while it does not affect the morphology of late endosomes both in non-neuronal and neuronal cells. Moreover, Synj1 loss impairs the recycling of transferrin, while it does not alter the trafficking of the epidermal growth factor receptor. The ectopic expression of Synj1 restores the functions of early endosomes, and rescues these trafficking defects in depleted cells. Importantly, the same alterations of early endosomal compartments and trafficking defects occur in fibroblasts of PARK20 patients. Our data indicate that Synj1 plays a crucial role in regulating the homeostasis and functions of early endosomal compartments in different cell types, and highlight defective cellular pathways in PARK20. In addition, they strengthen the link between endosomal trafficking and Parkinson’s disease.
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36
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Yamamoto W, Wada S, Nagano M, Aoshima K, Siekhaus DE, Toshima JY, Toshima J. Distinct roles for plasma membrane PtdIns(4)P and PtdIns(4,5)P 2 during receptor-mediated endocytosis in yeast. J Cell Sci 2018; 131:jcs.207696. [PMID: 29192062 DOI: 10.1242/jcs.207696] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 11/14/2017] [Indexed: 01/15/2023] Open
Abstract
Clathrin-mediated endocytosis requires the coordinated assembly of various endocytic proteins and lipids at the plasma membrane. Accumulating evidence demonstrates a crucial role for phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P2] in endocytosis but specific roles for phosphatidylinositol-4-phosphate [PtdIns(4)P], other than as the biosynthetic precursor of PtdIns(4,5)P2, have not been clarified. In this study we investigated the roles of PtdIns(4)P and PtdIns(4,5)P2 in receptor-mediated endocytosis through the construction of temperature-sensitive (ts) mutants for the phosphatidylinositol 4-kinases (PI4-kinases) Stt4p and Pik1p and the 1-phosphatidylinositol-4-phosphate 5-kinase [PtdIns(4) 5-kinase] Mss4p. Quantitative analyses of endocytosis revealed that both the stt4tspik1ts and mss4ts mutants have a severe defect in endocytic internalization. Live-cell imaging of endocytic protein dynamics in stt4tspik1ts and mss4ts mutants revealed that PtdIns(4)P is required for the recruitment of the α-factor receptor Ste2p to clathrin-coated pits, whereas PtdIns(4,5)P2 is required for membrane internalization. We also found that the localization to endocytic sites of the ENTH/ANTH domain-bearing clathrin adaptors, Ent1p, Ent2p, Yap1801p and Yap1802p, is significantly impaired in the stt4tspik1ts mutant but not in the mss4ts mutant. These results suggest distinct roles in successive steps for PtdIns(4)P and PtdIns(4,5)P2 during receptor-mediated endocytosis.
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Affiliation(s)
- Wataru Yamamoto
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Suguru Wada
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Makoto Nagano
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Kaito Aoshima
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
| | | | - Junko Y Toshima
- School of Health Science, Tokyo University of Technology, 5-23-22 Nishikamata, Ota-ku, Tokyo 144-8535, Japan
| | - Jiro Toshima
- Department of Biological Science and Technology, Tokyo University of Science, 6-3-1 Niijyuku, Katsushika-ku, Tokyo 125-8585, Japan
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37
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Ebrahimzadeh Z, Mukherjee A, Richard D. A map of the subcellular distribution of phosphoinositides in the erythrocytic cycle of the malaria parasite Plasmodium falciparum. Int J Parasitol 2017; 48:13-25. [PMID: 29154995 DOI: 10.1016/j.ijpara.2017.08.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 08/22/2017] [Accepted: 08/31/2017] [Indexed: 12/16/2022]
Abstract
Despite representing a small percentage of the cellular lipids of eukaryotic cells, phosphoinositides (PIPs) are critical in various processes such as intracellular trafficking and signal transduction. Central to their various functions is the differential distribution of PIP species to specific membrane compartments through the actions of kinases, phosphatases and lipases. Despite their importance in the malaria parasite lifecycle, the subcellular distribution of most PIP species in this organism is still unknown. We here localise several species of PIPs throughout the erythrocytic cycle of Plasmodium falciparum. We show that PI3P is mostly found at the apicoplast and the membrane of the food vacuole, that PI4P associates with the Golgi apparatus and the plasma membrane and that PI(4,5)P2, in addition to being detected at the plasma membrane, labels some cavity-like spherical structures. Finally, we show that the elusive PI5P localises to the plasma membrane, the nucleus and potentially to the transitional endoplasmic reticulum (ER). Our map of the subcellular distribution of PIP species in P. falciparum will be a useful tool to shed light on the dynamics of these lipids in this deadly parasite.
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Affiliation(s)
- Zeinab Ebrahimzadeh
- Centre de recherche en infectiologie, CRCHU de Québec-Université Laval, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada
| | - Angana Mukherjee
- Centre de recherche en infectiologie, CRCHU de Québec-Université Laval, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada
| | - Dave Richard
- Centre de recherche en infectiologie, CRCHU de Québec-Université Laval, 2705 Boul. Laurier, Québec, QC G1V 4G2, Canada.
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38
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Pinar M, Peñalva MA. Aspergillus nidulansBapH is a RAB11 effector that connects membranes in the Spitzenkörper with basal autophagy. Mol Microbiol 2017; 106:452-468. [DOI: 10.1111/mmi.13777] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/22/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Mario Pinar
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas del CSIC, Ramiro de Maeztu 9; Madrid 28040 Spain
| | - Miguel A. Peñalva
- Departamento de Biología Celular y Molecular; Centro de Investigaciones Biológicas del CSIC, Ramiro de Maeztu 9; Madrid 28040 Spain
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39
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Snider CE, Willet AH, Chen JS, Arpağ G, Zanic M, Gould KL. Phosphoinositide-mediated ring anchoring resists perpendicular forces to promote medial cytokinesis. J Cell Biol 2017; 216:3041-3050. [PMID: 28784611 PMCID: PMC5626552 DOI: 10.1083/jcb.201705070] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 06/23/2017] [Accepted: 07/07/2017] [Indexed: 11/27/2022] Open
Abstract
Altering phosphoinositide composition through deletion of efr3, a PI4 kinase scaffold, results in type V myosin-dependent cytokinetic ring sliding in Schizosaccharomyces pombe. Membrane-binding proteins contribute to ring anchoring to resist perpendicular forces and thereby promote medial cytokinesis. Many eukaryotic cells divide by assembling and constricting an actin- and myosin-based contractile ring (CR) that is physically linked to the plasma membrane (PM). In this study, we report that Schizosaccharomyces pombe cells lacking efr3, which encodes a conserved PM scaffold for the phosphatidylinositol-4 kinase Stt4, build CRs that can slide away from the cell middle during anaphase in a myosin V–dependent manner. The Efr3-dependent CR-anchoring mechanism is distinct from previously reported pathways dependent on the Fes/CIP4 homology Bin-Amphiphysin-Rvs167 (F-BAR) protein Cdc15 and paxillin Pxl1. In efr3Δ, the concentrations of several membrane-binding proteins were reduced in the CR and/or on the PM. Our results suggest that proper PM lipid composition is important to stabilize the central position of the CR and resist myosin V–based forces to promote the fidelity of cell division.
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Affiliation(s)
- Chloe E Snider
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
| | - Alaina H Willet
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
| | - Jun-Song Chen
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
| | - Göker Arpağ
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
| | - Marija Zanic
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
| | - Kathleen L Gould
- Department of Cell and Developmental Biology, Vanderbilt University, Nashville, TN
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40
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Hatakeyama R, Kono K, Yoshida S. Ypk1 and Ypk2 kinases maintain Rho1 at the plasma membrane by flippase-dependent lipid remodeling after membrane stresses. J Cell Sci 2017; 130:1169-1178. [PMID: 28167678 DOI: 10.1242/jcs.198382] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 02/01/2017] [Indexed: 01/15/2023] Open
Abstract
The plasma membrane (PM) is frequently challenged by mechanical stresses. In budding yeast, TORC2-Ypk1/Ypk2 kinase cascade plays a crucial role in PM stress responses by reorganizing the actin cytoskeleton via Rho1 GTPase. However, the molecular mechanism by which TORC2-Ypk1/Ypk2 regulates Rho1 is not well defined. Here, we found that Ypk1/Ypk2 maintain PM localization of Rho1 under PM stress via spatial reorganization of the lipids including phosphatidylserine. Genetic evidence suggests that this process is mediated by the Lem3-containing lipid flippase. We propose that lipid remodeling mediated by the TORC2-Ypk1/Ypk2-Lem3 axis is a backup mechanism for PM anchoring of Rho1 after PM stress-induced acute degradation of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2], which is responsible for Rho1 localization under normal conditions. Since all the signaling molecules studied here are conserved in higher eukaryotes, our findings might represent a general mechanism to cope with PM stress.
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Affiliation(s)
- Riko Hatakeyama
- Department of Biology and Rosenstiel Basic Biomedical Research Center, Brandeis University, 415 South Street, Waltham, MA 02454, USA .,Department of Biology, University of Fribourg, Chemin du Musée 10, Fribourg CH-1700, Switzerland
| | - Keiko Kono
- Department of Cell Biology, Graduate School of Medical Sciences, Nagoya City University, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan
| | - Satoshi Yoshida
- Department of Biology and Rosenstiel Basic Biomedical Research Center, Brandeis University, 415 South Street, Waltham, MA 02454, USA .,Gunma Initiative for Advanced Research (GIAR), Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma 371-8512, Japan.,Institute for Molecular and Cellular Regulation, Gunma University, 3-39-15 Showa-machi, Maebashi, Gunma 371-8512, Japan
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41
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Lipid transfer proteins and the tuning of compartmental identity in the Golgi apparatus. Chem Phys Lipids 2016; 200:42-61. [DOI: 10.1016/j.chemphyslip.2016.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 06/21/2016] [Accepted: 06/22/2016] [Indexed: 11/23/2022]
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42
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George AA, Hayden S, Stanton GR, Brockerhoff SE. Arf6 and the 5'phosphatase of synaptojanin 1 regulate autophagy in cone photoreceptors. Bioessays 2016; 38 Suppl 1:S119-35. [DOI: 10.1002/bies.201670913] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 11/19/2015] [Accepted: 11/20/2015] [Indexed: 12/26/2022]
Affiliation(s)
- Ashley A. George
- Department of Biochemistry; University of Washington; Seattle WA USA
| | - Sara Hayden
- Department of Biochemistry; University of Washington; Seattle WA USA
| | - Gail R. Stanton
- Department of Biochemistry; University of Washington; Seattle WA USA
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43
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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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44
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Schreij AMA, Fon EA, McPherson PS. Endocytic membrane trafficking and neurodegenerative disease. Cell Mol Life Sci 2016; 73:1529-45. [PMID: 26721251 PMCID: PMC11108351 DOI: 10.1007/s00018-015-2105-x] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 10/26/2015] [Accepted: 11/26/2015] [Indexed: 12/11/2022]
Abstract
Neurodegenerative diseases are amongst the most devastating of human disorders. New technologies have led to a rapid increase in the identification of disease-related genes with an enhanced appreciation of the key roles played by genetics in the etiology of these disorders. Importantly, pinpointing the normal function of disease gene proteins leads to new understanding of the cellular machineries and pathways that are altered in the disease process. One such emerging pathway is membrane trafficking in the endosomal system. This key cellular process controls the localization and levels of a myriad of proteins and is thus critical for normal cell function. In this review we will focus on three neurodegenerative diseases; Parkinson disease, amyotrophic lateral sclerosis, and hereditary spastic paraplegias, for which a large number of newly discovered disease genes encode proteins that function in endosomal membrane trafficking. We will describe how alterations in these proteins affect endosomal function and speculate on the contributions of these disruptions to disease pathophysiology.
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Affiliation(s)
- Andrea M A Schreij
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC, H3A 2B4, Canada
| | - Edward A Fon
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC, H3A 2B4, Canada
| | - Peter S McPherson
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC, H3A 2B4, Canada.
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45
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Domingues L, Ismail A, Charro N, Rodríguez-Escudero I, Holden DW, Molina M, Cid VJ, Mota LJ. The Salmonella effector SteA binds phosphatidylinositol 4-phosphate for subcellular targeting within host cells. Cell Microbiol 2016; 18:949-69. [PMID: 26676327 DOI: 10.1111/cmi.12558] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 11/23/2015] [Accepted: 12/09/2015] [Indexed: 12/21/2022]
Abstract
Many bacterial pathogens use specialized secretion systems to deliver virulence effector proteins into eukaryotic host cells. The function of these effectors depends on their localization within infected cells, but the mechanisms determining subcellular targeting of each effector are mostly elusive. Here, we show that the Salmonella type III secretion effector SteA binds specifically to phosphatidylinositol 4-phosphate [PI(4)P]. Ectopically expressed SteA localized at the plasma membrane (PM) of eukaryotic cells. However, SteA was displaced from the PM of Saccharomyces cerevisiae in mutants unable to synthesize the local pool of PI(4)P and from the PM of HeLa cells after localized depletion of PI(4)P. Moreover, in infected cells, bacterially translocated or ectopically expressed SteA localized at the membrane of the Salmonella-containing vacuole (SCV) and to Salmonella-induced tubules; using the PI(4)P-binding domain of the Legionella type IV secretion effector SidC as probe, we found PI(4)P at the SCV membrane and associated tubules throughout Salmonella infection of HeLa cells. Both binding of SteA to PI(4)P and the subcellular localization of ectopically expressed or bacterially translocated SteA were dependent on a lysine residue near the N-terminus of the protein. Overall, this indicates that binding of SteA to PI(4)P is necessary for its localization within host cells.
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Affiliation(s)
- Lia Domingues
- UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa (FCT NOVA), Caparica, Portugal.,Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, Portugal
| | - Ahmad Ismail
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigación Sanitaria (IRyCIS), Madrid, Spain
| | - Nuno Charro
- UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa (FCT NOVA), Caparica, Portugal
| | - Isabel Rodríguez-Escudero
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigación Sanitaria (IRyCIS), Madrid, Spain
| | - David W Holden
- MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - María Molina
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigación Sanitaria (IRyCIS), Madrid, Spain
| | - Víctor J Cid
- Departamento de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid and Instituto Ramón y Cajal de Investigación Sanitaria (IRyCIS), Madrid, Spain
| | - Luís Jaime Mota
- UCIBIO-REQUIMTE, Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa (FCT NOVA), Caparica, Portugal.,Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Oeiras, Portugal
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46
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Alvaro CG, Thorner J. Heterotrimeric G Protein-coupled Receptor Signaling in Yeast Mating Pheromone Response. J Biol Chem 2016; 291:7788-95. [PMID: 26907689 PMCID: PMC4824985 DOI: 10.1074/jbc.r116.714980] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The DNAs encoding the receptors that respond to the peptide mating pheromones of the budding yeast Saccharomyces cerevisiae were isolated in 1985, and were the very first genes for agonist-binding heterotrimeric G protein-coupled receptors (GPCRs) to be cloned in any organism. Now, over 30 years later, this yeast and its receptors continue to provide a pathfinding experimental paradigm for investigating GPCR-initiated signaling and its regulation, as described in this retrospective overview.
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Affiliation(s)
- Christopher G Alvaro
- From the Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
| | - Jeremy Thorner
- From the Division of Biochemistry, Biophysics and Structural Biology, Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3202
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47
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George AA, Hayden S, Stanton GR, Brockerhoff SE. Arf6 and the 5'phosphatase of Synaptojanin 1 regulate autophagy in cone photoreceptors. ACTA ACUST UNITED AC 2016; 1:117-133. [PMID: 27123470 DOI: 10.1002/icl3.1044] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Abnormalities in the ability of cells to properly degrade proteins have been identified in many neurodegenerative diseases. Recent work has implicated Synaptojanin 1 (SynJ1) in Alzheimer's disease and Parkinson's disease, although the role of this polyphosphoinositide phosphatase in protein degradation has not been thoroughly described. Here we dissected in vivo the role of SynJ1 in endolysosomal trafficking in zebrafish cone photoreceptors using a SynJ1-deficient zebrafish mutant, nrca14 . We found that loss of SynJ1 leads to specific accumulation of late endosomes and autophagosomes early in photoreceptor development. An analysis of autophagic flux revealed that autophagosomes accumulate due to a defect in maturation. In addition we found an increase in vesicles that are highly enriched for PI(3)P, but negative for an early endosome marker in nrca14 cones. A mutational analysis of SynJ1 enzymatic domains found that activity of the 5' phosphatase, but not the Sac1 domain, is required to rescue both aberrant late endosomes and autophagosomes. Finally, modulating activity of the PI(4,5)P2 regulator, Arf6, rescued the disrupted trafficking pathways in nrca14 cones. Our study describes a specific role for SynJ1 in autophagosomal and endosomal trafficking and provides evidence that PI(4,5)P2 participates in autophagy in a neuronal cell type.
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Affiliation(s)
- Ashley A George
- Department of Biochemistry, University of Washington, 1959 NE Pacific St, Seattle, WA, 98195, USA
| | - Sara Hayden
- Department of Biochemistry, University of Washington, 1959 NE Pacific St, Seattle, WA, 98195, USA
| | - Gail R Stanton
- Department of Biochemistry, University of Washington, 1959 NE Pacific St, Seattle, WA, 98195, USA
| | - Susan E Brockerhoff
- Department of Biochemistry, University of Washington, 1959 NE Pacific St, Seattle, WA, 98195, USA
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Córcoles-Sáez I, Hernández ML, Martínez-Rivas JM, Prieto JA, Randez-Gil F. Characterization of the S. cerevisiae inp51 mutant links phosphatidylinositol 4,5-bisphosphate levels with lipid content, membrane fluidity and cold growth. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1861:213-26. [PMID: 26724696 DOI: 10.1016/j.bbalip.2015.12.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 12/15/2015] [Accepted: 12/18/2015] [Indexed: 11/30/2022]
Abstract
Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and its derivatives diphosphoinositol phosphates (DPIPs) play key signaling and regulatory roles. However, a direct function of these molecules in lipid and membrane homeostasis remains obscure. Here, we have studied the cold tolerance phenotype of yeast cells lacking the Inp51-mediated phosphoinositide-5-phosphatase. Genetic and biochemical approaches showed that increased metabolism of PI(4,5)P2 reduces the activity of the Pho85 kinase by increasing the levels of the DPIP isomer 1-IP7. This effect was key in the cold tolerance phenotype. Indeed, pho85 mutant cells grew better than the wild-type at 15 °C, and lack of this kinase abolished the inp51-mediated cold phenotype. Remarkably, reduced Pho85 function by loss of Inp51 affected the activity of the Pho85-regulated target Pah1, the yeast phosphatidate phosphatase. Cells lacking Inp51 showed reduced Pah1 abundance, derepression of an INO1-lacZ reporter, decreased content of triacylglycerides and elevated levels of phosphatidate, hallmarks of the pah1 mutant. However, the inp51 phenotype was not associated to low Pah1 activity since deletion of PAH1 caused cold sensitivity. In addition, the inp51 mutant exhibited features not shared by pah1, including a 40%-reduction in total lipid content and decreased membrane fluidity. These changes may influence the activity of membrane-anchored and/or associated proteins since deletion of INP51 slows down the transit to the vacuole of the fluorescent dye FM4-64. In conclusion, our work supports a model in which changes in the PI(4,5)P2 pool affect the 1-IP7 levels modulating the activity of Pho85, Pah1 and likely additional Pho85-controlled targets, and regulate lipid composition and membrane properties.
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Affiliation(s)
- Isaac Córcoles-Sáez
- Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Maria Luisa Hernández
- Instituto de la Grasa, Consejo Superior de Investigaciones Científicas (CSIC), Sevilla, Spain
| | | | - Jose A Prieto
- Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain
| | - Francisca Randez-Gil
- Instituto de Agroquímica y Tecnología de los Alimentos, Consejo Superior de Investigaciones Científicas (CSIC), Paterna, Valencia, Spain.
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49
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Fernández-Acero T, Rodríguez-Escudero I, Molina M, Cid VJ. The yeast cell wall integrity pathway signals from recycling endosomes upon elimination of phosphatidylinositol (4,5)-bisphosphate by mammalian phosphatidylinositol 3-kinase. Cell Signal 2015; 27:2272-84. [PMID: 26261079 DOI: 10.1016/j.cellsig.2015.08.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 08/05/2015] [Indexed: 11/29/2022]
Abstract
Phosphatidylinositol (4,5)-bisphosphate [PtdIns(4,5)P(2)] is essential for recognition of the plasma membrane inner leaf by protein complexes. We expressed mammalian class I phosphoinositide 3-kinase (PI3K) in Saccharomyces cerevisiae to eliminate PtdIns(4,5)P(2) by its conversion into PtdIns(3,4,5)P(3), a lipid naturally missing in this yeast. This led to loss of actin function and endocytosis defects, causing a blockage in polarized secretion. Also, the cell wall integrity (CWI) mitogen-activated protein kinase (MAPK) pathway was activated, triggering a typical transcriptional response. In the absence of PtdIns(4,5)P(2) at the plasma membrane, the Pkc1 protein kinase upstream the CWI MAPK module localized to post-Golgi endosomes marked by SNARE Snc1 and Rab GTPases Ypt31 and Ypt32. Other components at the head of the pathway, like the mechanosensor Wsc1, the GTPase Rho1 and its activator the GDP/GTP exchange factor Rom2, co-localized with Pkc1 in these compartments. Chemical inhibition of PI3K proved that both CWI activation and Pkc1 relocation to endosomes are reversible. These results suggest that the CWI pathway is able to respond to loss of plasma membrane identity from recycling endosomes.
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Affiliation(s)
- Teresa Fernández-Acero
- Dpto. de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain; Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS), Madrid, Spain
| | - Isabel Rodríguez-Escudero
- Dpto. de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain; Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS), Madrid, Spain
| | - María Molina
- Dpto. de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain; Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS), Madrid, Spain.
| | - Víctor J Cid
- Dpto. de Microbiología II, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain; Instituto Ramón y Cajal de Investigaciones Sanitarias (IRYCIS), Madrid, Spain
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50
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Comparative Analysis of Transmembrane Regulators of the Filamentous Growth Mitogen-Activated Protein Kinase Pathway Uncovers Functional and Regulatory Differences. EUKARYOTIC CELL 2015; 14:868-83. [PMID: 26116211 DOI: 10.1128/ec.00085-15] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Accepted: 06/17/2015] [Indexed: 12/14/2022]
Abstract
Filamentous growth is a microbial differentiation response that involves the concerted action of multiple signaling pathways. In budding yeast, one pathway that regulates filamentous growth is a Cdc42p-dependent mitogen-activated protein kinase (MAPK) pathway. Several transmembrane (TM) proteins regulate the filamentous growth pathway, including the signaling mucin Msb2p, the tetraspan osmosensor Sho1p, and an adaptor Opy2p. The TM proteins were compared to identify common and unique features. Msb2p, Sho1p, and Opy2p associated by coimmunoprecipitation analysis but showed predominantly different localization patterns. The different localization patterns of the proteins resulted in part from different rates of turnover from the plasma membrane (PM). In particular, Msb2p (and Opy2p) were turned over rapidly compared to Sho1p. Msb2p signaled from the PM, and its turnover was a rate-limiting step in MAPK signaling. Genetic analysis identified unique phenotypes of cells overexpressing the TM proteins. Therefore, each TM regulator of the filamentous growth pathway has its own regulatory pattern and specific function in regulating filamentous growth. This specialization may be important for fine-tuning and potentially diversifying the filamentation response.
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