1
|
Gnyliukh N, Johnson A, Nagel MK, Monzer A, Babić D, Hlavata A, Alotaibi SS, Isono E, Loose M, Friml J. Role of the dynamin-related protein 2 family and SH3P2 in clathrin-mediated endocytosis in Arabidopsis thaliana. J Cell Sci 2024; 137:jcs261720. [PMID: 38506228 PMCID: PMC11112126 DOI: 10.1242/jcs.261720] [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: 10/11/2023] [Accepted: 03/12/2024] [Indexed: 03/21/2024] Open
Abstract
Clathrin-mediated endocytosis (CME) is vital for the regulation of plant growth and development through controlling plasma membrane protein composition and cargo uptake. CME relies on the precise recruitment of regulators for vesicle maturation and release. Homologues of components of mammalian vesicle scission are strong candidates to be part of the scission machinery in plants, but the precise roles of these proteins in this process are not fully understood. Here, we characterised the roles of the plant dynamin-related protein 2 (DRP2) family (hereafter DRP2s) and SH3-domain containing protein 2 (SH3P2), the plant homologue to recruiters of dynamins, such as endophilin and amphiphysin, in CME by combining high-resolution imaging of endocytic events in vivo and characterisation of the purified proteins in vitro. Although DRP2s and SH3P2 arrive similarly late during CME and physically interact, genetic analysis of the sh3p123 triple mutant and complementation assays with non-SH3P2-interacting DRP2 variants suggest that SH3P2 does not directly recruit DRP2s to the site of endocytosis. These observations imply that, despite the presence of many well-conserved endocytic components, plants have acquired a distinct mechanism for CME.
Collapse
Affiliation(s)
- Nataliia Gnyliukh
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - Alexander Johnson
- Division of Anatomy, Centre for Anatomy & Cell Biology, Medical University of Vienna, 1090 Vienna, Austria
| | | | - Aline Monzer
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - David Babić
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - Annamaria Hlavata
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - Saqer S. Alotaibi
- Department of Biotechnology, College of Science, Taif University, Taif 21944, Saudi Arabia
| | - Erika Isono
- Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | - Martin Loose
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| | - Jiří Friml
- Institute of Science and Technology Austria (ISTA), 3400 Klosterneuburg, Austria
| |
Collapse
|
2
|
Ling P, Ju J, Zhang X, Wei W, Luo J, Li Y, Hai H, Shang B, Cheng H, Wang C, Zhang X, Su J. The Silencing of GhPIP5K2 and GhPIP5K22 Weakens Abiotic Stress Tolerance in Upland Cotton ( Gossypium hirsutum). Int J Mol Sci 2024; 25:1511. [PMID: 38338791 PMCID: PMC10855785 DOI: 10.3390/ijms25031511] [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: 11/21/2023] [Revised: 01/09/2024] [Accepted: 01/12/2024] [Indexed: 02/12/2024] Open
Abstract
Phosphatidylinositol 4-phosphate 5-kinases (PIP5Ks), essential enzymes in the phosphatidylinositol signaling pathway, are crucial for the abiotic stress responses and the overall growth and development of plants. However, the GhPIP5Ks had not been systematically studied, and their function in upland cotton was unknown. This study identified a total of 28 GhPIP5Ks, and determined their chromosomal locations, gene structures, protein motifs and cis-acting elements via bioinformatics analysis. A quantitative real-time PCR (qRT‒PCR) analysis showed that most GhPIP5Ks were upregulated under different stresses. A virus-induced gene silencing (VIGS) assay indicated that the superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) activities were significantly decreased, while malondialdehyde (MDA) content were significantly increased in GhPIP5K2- and GhPIP5K22-silenced upland cotton plants under abiotic stress. Furthermore, the expression of the stress marker genes GhHSFB2A, GhHSFB2B, GhDREB2A, GhDREB2C, GhRD20-1, GhRD29A, GhBIN2, GhCBL3, GhNHX1, GhPP2C, GhCBF1, GhSnRK2.6 and GhCIPK6 was significantly decreased in the silenced plants after exposure to stress. These results revealed that the silencing of GhPIP5K2 and GhPIP5K22 weakened the tolerance to abiotic stresses. These discoveries provide a foundation for further inquiry into the actions of the GhPIP5K gene family in regulating the response and resistance mechanisms of cotton to abiotic stresses.
Collapse
Affiliation(s)
- Pingjie Ling
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Jisheng Ju
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Xueli Zhang
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Wei Wei
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Jin Luo
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Ying Li
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Han Hai
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Bowen Shang
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Hongbo Cheng
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Caixiang Wang
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
| | - Xianliang Zhang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences (CAAS), Anyang 455000, China
- Western Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Changji 831100, China
| | - Junji Su
- College of Life Science and Technology, Gansu Agricultural University, Lanzhou 730070, China; (P.L.); (J.J.); (X.Z.); (W.W.); (J.L.); (Y.L.); (H.H.); (B.S.); (H.C.); (C.W.)
- Western Research Institute, Chinese Academy of Agricultural Sciences (CAAS), Changji 831100, China
| |
Collapse
|
3
|
Zhang W, Ding D, Lu Y, Chen H, Jiang P, Zuo P, Wang G, Luo J, Yin Y, Luo J, Yin Y. Structural and functional insights into the lipid regulation of human anion exchanger 2. Nat Commun 2024; 15:759. [PMID: 38272905 PMCID: PMC10810954 DOI: 10.1038/s41467-024-44966-0] [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: 06/06/2023] [Accepted: 01/11/2024] [Indexed: 01/27/2024] Open
Abstract
Anion exchanger 2 (AE2) is an electroneutral Na+-independent Cl-/HCO3- exchanger belongs to the SLC4 transporter family. The widely expressed AE2 participates in a variety of physiological processes, including transepithelial acid-base secretion and osteoclastogenesis. Both the transmembrane domains (TMDs) and the N-terminal cytoplasmic domain (NTD) are involved in regulation of AE2 activity. However, the regulatory mechanism remains unclear. Here, we report a 3.2 Å cryo-EM structure of the AE2 TMDs in complex with PIP2 and a 3.3 Å full-length mutant AE2 structure in the resting state without PIP2. We demonstrate that PIP2 at the TMD dimer interface is involved in the substrate exchange process. Mutation in the PIP2 binding site leads to the displacement of TM7 and further stabilizes the interaction between the TMD and the NTD. Reduced substrate transport activity and conformation similar to AE2 in acidic pH indicating the central contribution of PIP2 to the function of AE2.
Collapse
Affiliation(s)
- Weiqi Zhang
- Institute of Systems Biomedicine, Department of Pathology, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Dian Ding
- Institute of Systems Biomedicine, Department of Pathology, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Yishuo Lu
- Institute of Systems Biomedicine, Department of Pathology, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Hongyi Chen
- Institute of Systems Biomedicine, Department of Pathology, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Peijun Jiang
- Institute of Systems Biomedicine, Department of Pathology, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Peng Zuo
- Institute of Systems Biomedicine, Department of Pathology, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Guangxi Wang
- Institute of Systems Biomedicine, Department of Pathology, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China
| | - Juan Luo
- Institute of Precision Medicine, Peking University Shenzhen Hospital, Shenzhen, 518036, China
| | - Yue Yin
- Department of Pharmacology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Jianyuan Luo
- Department of Medical Genetics, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China
| | - Yuxin Yin
- Institute of Systems Biomedicine, Department of Pathology, Beijing Key Laboratory of Tumor Systems Biology, Peking-Tsinghua Center for Life Sciences, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, 100191, China.
- Institute of Precision Medicine, Peking University Shenzhen Hospital, Shenzhen, 518036, China.
| |
Collapse
|
4
|
Cabrera-Rodríguez R, Pérez-Yanes S, Lorenzo-Sánchez I, Trujillo-González R, Estévez-Herrera J, García-Luis J, Valenzuela-Fernández A. HIV Infection: Shaping the Complex, Dynamic, and Interconnected Network of the Cytoskeleton. Int J Mol Sci 2023; 24:13104. [PMID: 37685911 PMCID: PMC10487602 DOI: 10.3390/ijms241713104] [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: 08/08/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 09/10/2023] Open
Abstract
HIV-1 has evolved a plethora of strategies to overcome the cytoskeletal barrier (i.e., actin and intermediate filaments (AFs and IFs) and microtubules (MTs)) to achieve the viral cycle. HIV-1 modifies cytoskeletal organization and dynamics by acting on associated adaptors and molecular motors to productively fuse, enter, and infect cells and then traffic to the cell surface, where virions assemble and are released to spread infection. The HIV-1 envelope (Env) initiates the cycle by binding to and signaling through its main cell surface receptors (CD4/CCR5/CXCR4) to shape the cytoskeleton for fusion pore formation, which permits viral core entry. Then, the HIV-1 capsid is transported to the nucleus associated with cytoskeleton tracks under the control of specific adaptors/molecular motors, as well as HIV-1 accessory proteins. Furthermore, HIV-1 drives the late stages of the viral cycle by regulating cytoskeleton dynamics to assure viral Pr55Gag expression and transport to the cell surface, where it assembles and buds to mature infectious virions. In this review, we therefore analyze how HIV-1 generates a cell-permissive state to infection by regulating the cytoskeleton and associated factors. Likewise, we discuss the relevance of this knowledge to understand HIV-1 infection and pathogenesis in patients and to develop therapeutic strategies to battle HIV-1.
Collapse
Affiliation(s)
- Romina Cabrera-Rodríguez
- Laboratorio de Inmunología Celular y Viral, Unidad de Farmacología, Sección de Medicina, Facultad de Ciencias de la Salud, Universidad de La Laguna (ULL), 38200 La Laguna, Spain; (R.C.-R.); (S.P.-Y.); (I.L.-S.); (R.T.-G.); (J.E.-H.); (J.G.-L.)
| | - Silvia Pérez-Yanes
- Laboratorio de Inmunología Celular y Viral, Unidad de Farmacología, Sección de Medicina, Facultad de Ciencias de la Salud, Universidad de La Laguna (ULL), 38200 La Laguna, Spain; (R.C.-R.); (S.P.-Y.); (I.L.-S.); (R.T.-G.); (J.E.-H.); (J.G.-L.)
| | - Iria Lorenzo-Sánchez
- Laboratorio de Inmunología Celular y Viral, Unidad de Farmacología, Sección de Medicina, Facultad de Ciencias de la Salud, Universidad de La Laguna (ULL), 38200 La Laguna, Spain; (R.C.-R.); (S.P.-Y.); (I.L.-S.); (R.T.-G.); (J.E.-H.); (J.G.-L.)
| | - Rodrigo Trujillo-González
- Laboratorio de Inmunología Celular y Viral, Unidad de Farmacología, Sección de Medicina, Facultad de Ciencias de la Salud, Universidad de La Laguna (ULL), 38200 La Laguna, Spain; (R.C.-R.); (S.P.-Y.); (I.L.-S.); (R.T.-G.); (J.E.-H.); (J.G.-L.)
- Analysis Department, Faculty of Mathematics, Universidad de La Laguna (ULL), 38200 La Laguna, Spain
| | - Judith Estévez-Herrera
- Laboratorio de Inmunología Celular y Viral, Unidad de Farmacología, Sección de Medicina, Facultad de Ciencias de la Salud, Universidad de La Laguna (ULL), 38200 La Laguna, Spain; (R.C.-R.); (S.P.-Y.); (I.L.-S.); (R.T.-G.); (J.E.-H.); (J.G.-L.)
| | - Jonay García-Luis
- Laboratorio de Inmunología Celular y Viral, Unidad de Farmacología, Sección de Medicina, Facultad de Ciencias de la Salud, Universidad de La Laguna (ULL), 38200 La Laguna, Spain; (R.C.-R.); (S.P.-Y.); (I.L.-S.); (R.T.-G.); (J.E.-H.); (J.G.-L.)
| | - Agustín Valenzuela-Fernández
- Laboratorio de Inmunología Celular y Viral, Unidad de Farmacología, Sección de Medicina, Facultad de Ciencias de la Salud, Universidad de La Laguna (ULL), 38200 La Laguna, Spain; (R.C.-R.); (S.P.-Y.); (I.L.-S.); (R.T.-G.); (J.E.-H.); (J.G.-L.)
| |
Collapse
|
5
|
Pereira D, Santamaria A, Pawar N, Carrascosa-Tejedor J, Sardo M, Mafra L, Guzmán E, Owen DJ, Zaccai NR, Maestro A, Marín-Montesinos I. Engineering phosphatidylinositol-4,5-bisphosphate model membranes enriched in endocytic cargo: A neutron reflectometry, AFM and QCM-D structural study. Colloids Surf B Biointerfaces 2023; 227:113341. [PMID: 37210796 DOI: 10.1016/j.colsurfb.2023.113341] [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: 03/11/2023] [Revised: 05/05/2023] [Accepted: 05/09/2023] [Indexed: 05/23/2023]
Abstract
The combination of in vitro models of biological membranes based on solid-supported lipid bilayers (SLBs) and of surface sensitive techniques, such as neutron reflectometry (NR), atomic force microscopy (AFM) and quartz crystal microbalance with dissipation monitoring (QCM-D), is well suited to provide quantitative information about molecular level interactions and lipid spatial distributions. In this work, cellular plasma membranes have been mimicked by designing complex SLB, containing phosphatidylinositol 4,5-bisphosphate (PtdIns4,5P2) lipids as well as incorporating synthetic lipo-peptides that simulate the cytoplasmic tails of transmembrane proteins. The QCM-D results revealed that the adsorption and fusion kinetics of PtdIns4,5P2 are highly dependent of Mg2+. Additionally, it was shown that increasing concentrations of PtdIns4,5P2 leads to the formation of SLBs with higher homogeneity. The presence of PtdIns4,5P2 clusters was visualized by AFM. NR provided important insights about the structural organization of the various components within the SLB, highlighting that the leaflet symmetry of these SLBs is broken by the presence of CD4-derived cargo peptides. Finally, we foresee our study to be a starting point for more sophisticated in vitro models of biological membranes with the incorporation of inositol phospholipids and synthetic endocytic motifs.
Collapse
Affiliation(s)
- Daniel Pereira
- Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro, Portugal; Large Scale Structures Group, Institut Laue-Langevin, 38042 Cedex 9, Grenoble, France
| | - Andreas Santamaria
- Large Scale Structures Group, Institut Laue-Langevin, 38042 Cedex 9, Grenoble, France; Departamento de Química Física, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - Nisha Pawar
- Centro de Fı́sica de Materiales (CSIC, UPV/EHU) - Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain
| | - Javier Carrascosa-Tejedor
- Large Scale Structures Group, Institut Laue-Langevin, 38042 Cedex 9, Grenoble, France; Division of Pharmacy and Optometry, University of Manchester, M13 9PT Manchester, UK
| | - Mariana Sardo
- Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Luís Mafra
- Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Eduardo Guzmán
- Departamento de Química Física, Universidad Complutense de Madrid, 28040, Madrid, Spain; Instituto Pluridisciplinar, Universidad Complutense de Madrid, 28040 Madrid, Spain
| | - David J Owen
- Cambridge Institute for Medical Research, University of Cambridge, CB22 7QQ Cambridge, UK
| | - Nathan R Zaccai
- Cambridge Institute for Medical Research, University of Cambridge, CB22 7QQ Cambridge, UK
| | - Armando Maestro
- Centro de Fı́sica de Materiales (CSIC, UPV/EHU) - Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain; IKERBASQUE-Basque Foundation for Science, Plaza Euskadi 5, Bilbao 48009, Spain.
| | | |
Collapse
|
6
|
Kanemaru K, Nakamura Y. Activation Mechanisms and Diverse Functions of Mammalian Phospholipase C. Biomolecules 2023; 13:915. [PMID: 37371495 DOI: 10.3390/biom13060915] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 05/28/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
Phospholipase C (PLC) plays pivotal roles in regulating various cellular functions by metabolizing phosphatidylinositol 4,5-bisphosphate in the plasma membrane. This process generates two second messengers, inositol 1,4,5-trisphosphate and diacylglycerol, which respectively regulate the intracellular Ca2+ levels and protein kinase C activation. In mammals, six classes of typical PLC have been identified and classified based on their structure and activation mechanisms. They all share X and Y domains, which are responsible for enzymatic activity, as well as subtype-specific domains. Furthermore, in addition to typical PLC, atypical PLC with unique structures solely harboring an X domain has been recently discovered. Collectively, seven classes and 16 isozymes of mammalian PLC are known to date. Dysregulation of PLC activity has been implicated in several pathophysiological conditions, including cancer, cardiovascular diseases, and neurological disorders. Therefore, identification of new drug targets that can selectively modulate PLC activity is important. The present review focuses on the structures, activation mechanisms, and physiological functions of mammalian PLC.
Collapse
Affiliation(s)
- Kaori Kanemaru
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Chiba 278-8510, Japan
| | - Yoshikazu Nakamura
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Chiba 278-8510, Japan
| |
Collapse
|
7
|
Raut P, Obeng B, Waters H, Zimmerberg J, Gosse JA, Hess ST. Phosphatidylinositol 4,5-Bisphosphate Mediates the Co-Distribution of Influenza A Hemagglutinin and Matrix Protein M1 at the Plasma Membrane. Viruses 2022; 14:v14112509. [PMID: 36423118 PMCID: PMC9698905 DOI: 10.3390/v14112509] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/04/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
The fully assembled influenza A virus (IAV) has on its surface the highest density of a single membrane protein found in nature-the glycoprotein hemagglutinin (HA) that mediates viral binding, entry, and assembly. HA clusters at the plasma membrane of infected cells, and the HA density (number of molecules per unit area) of these clusters correlates with the infectivity of the virus. Dense HA clusters are considered to mark the assembly site and ultimately lead to the budding of infectious IAV. The mechanism of spontaneous HA clustering, which occurs with or without other viral components, has not been elucidated. Using super-resolution fluorescence photoactivation localization microscopy (FPALM), we have previously shown that these HA clusters are interdependent on phosphatidylinositol 4,5-biphosphate (PIP2). Here, we show that the IAV matrix protein M1 co-clusters with PIP2, visualized using the pleckstrin homology domain. We find that cetylpyridinium chloride (CPC), which is a positively charged quaternary ammonium compound known for its antibacterial and antiviral properties at millimolar concentrations, disrupts M1 clustering and M1-PIP2 co-clustering at micromolar concentrations well below the critical micelle concentration (CMC). CPC also disrupts the co-clustering of M1 with HA at the plasma membrane, suggesting the role of host cell PIP2 clusters as scaffolds for gathering and concentrating M1 and HA to achieve their unusually high cluster densities in the IAV envelope.
Collapse
Affiliation(s)
- Prakash Raut
- Department of Physics and Astronomy, University of Maine, Orono, ME 04469-5709, USA
| | - Bright Obeng
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469-5735, USA
| | - Hang Waters
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-1855, USA
| | - Joshua Zimmerberg
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-1855, USA
| | - Julie A. Gosse
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, ME 04469-5735, USA
| | - Samuel T. Hess
- Department of Physics and Astronomy, University of Maine, Orono, ME 04469-5709, USA
- Correspondence:
| |
Collapse
|
8
|
Fadil SA, Janetopoulos C. The Polarized Redistribution of the Contractile Vacuole to the Rear of the Cell is Critical for Streaming and is Regulated by PI(4,5)P2-Mediated Exocytosis. Front Cell Dev Biol 2022; 9:765316. [PMID: 35928786 PMCID: PMC9344532 DOI: 10.3389/fcell.2021.765316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 10/20/2021] [Indexed: 12/05/2022] Open
Abstract
Dictyostelium discoideum amoebae align in a head to tail manner during the process of streaming during fruiting body formation. The chemoattractant cAMP is the chemoattractant regulating cell migration during this process and is released from the rear of cells. The process by which this cAMP release occurs has eluded investigators for many decades, but new findings suggest that this release can occur through expulsion during contractile vacuole (CV) ejection. The CV is an organelle that performs several functions inside the cell including the regulation of osmolarity, and discharges its content via exocytosis. The CV localizes to the rear of the cell and appears to be part of the polarity network, with the localization under the influence of the plasma membrane (PM) lipids, including the phosphoinositides (PIs), among those is PI(4,5)P2, the most abundant PI on the PM. Research on D. discoideum and neutrophils have shown that PI(4,5)P2 is enriched at the rear of migrating cells. In several systems, it has been shown that the essential regulator of exocytosis is through the exocyst complex, mediated in part by PI(4,5)P2-binding. This review features the role of the CV complex in D. discoideum signaling with a focus on the role of PI(4,5)P2 in regulating CV exocytosis and localization. Many of the regulators of these processes are conserved during evolution, so the mechanisms controlling exocytosis and membrane trafficking in D. discoideum and mammalian cells will be discussed, highlighting their important functions in membrane trafficking and signaling in health and disease.
Collapse
Affiliation(s)
- Sana A. Fadil
- Department of Biological Sciences, University of the Sciences in Philadelphia, Philadelphia, PA, United States
- Department of Natural product, Faculty of Pharmacy, King Abdulaziz University, Saudia Arabia
| | - Chris Janetopoulos
- Department of Biological Sciences, University of the Sciences in Philadelphia, Philadelphia, PA, United States
- The Science Research Institute, Albright College, Reading, PA, United States
- The Department of Cell Biology at Johns Hopkins University School of Medicine, Baltimore, MD, United States
- *Correspondence: Chris Janetopoulos,
| |
Collapse
|
9
|
Borges-Araújo L, Monteiro ME, Mil-Homens D, Bernardes N, Sarmento MJ, Coutinho A, Prieto M, Fernandes F. Impact of Ca 2+-Induced PI(4,5)P 2 Clusters on PH-YFP Organization and Protein-Protein Interactions. Biomolecules 2022; 12:912. [PMID: 35883468 PMCID: PMC9312469 DOI: 10.3390/biom12070912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 06/22/2022] [Accepted: 06/27/2022] [Indexed: 11/16/2022] Open
Abstract
Despite its low abundance, phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) is a key modulator of membrane-associated signaling events in eukaryotic cells. Temporal and spatial regulation of PI(4,5)P2 concentration can achieve localized increases in the levels of this lipid, which are crucial for the activation or recruitment of peripheral proteins to the plasma membrane. The recent observation of the dramatic impact of physiological divalent cation concentrations on PI(4,5)P2 clustering, suggests that protein anchoring to the plasma membrane through PI(4,5)P2 is likely not defined solely by a simple (monomeric PI(4,5)P2)/(protein bound PI(4,5)P2) equilibrium, but instead depends on complex protein interactions with PI(4,5)P2 clusters. The insertion of PI(4,5)P2-binding proteins within these clusters can putatively modulate protein-protein interactions in the membrane, but the relevance of such effects is largely unknown. In this work, we characterized the impact of Ca2+ on the organization and protein-protein interactions of PI(4,5)P2-binding proteins. We show that, in giant unilamellar vesicles presenting PI(4,5)P2, the membrane diffusion properties of pleckstrin homology (PH) domains tagged with a yellow fluorescent protein (YFP) are affected by the presence of Ca2+, suggesting direct interactions between the protein and PI(4,5)P2 clusters. Importantly, PH-YFP is found to dimerize in the membrane in the absence of Ca2+. This oligomerization is inhibited in the presence of physiological concentrations of the divalent cation. These results confirm that cation-dependent PI(4,5)P2 clustering promotes interactions between PI(4,5)P2-binding proteins and has the potential to dramatically influence the organization and downstream interactions of PI(4,5)P2-binding proteins in the plasma membrane.
Collapse
Affiliation(s)
- Luís Borges-Araújo
- IBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal; (L.B.-A.); (D.M.-H.); (N.B.); (A.C.); (M.P.)
- Associate Laboratory i4HB—Institute for Health and Bioeconomy at Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal
| | - Marina E. Monteiro
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal; (M.E.M.); (M.J.S.)
| | - Dalila Mil-Homens
- IBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal; (L.B.-A.); (D.M.-H.); (N.B.); (A.C.); (M.P.)
- Associate Laboratory i4HB—Institute for Health and Bioeconomy at Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal
| | - Nuno Bernardes
- IBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal; (L.B.-A.); (D.M.-H.); (N.B.); (A.C.); (M.P.)
- Associate Laboratory i4HB—Institute for Health and Bioeconomy at Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal
| | - Maria J. Sarmento
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal; (M.E.M.); (M.J.S.)
- Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Avenida Prof. Egas Moniz, 1649-028 Lisbon, Portugal
| | - Ana Coutinho
- IBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal; (L.B.-A.); (D.M.-H.); (N.B.); (A.C.); (M.P.)
- Associate Laboratory i4HB—Institute for Health and Bioeconomy at Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal
- Departamento de Química e Bioquímica, Faculty of Sciences, University of Lisbon, 1749-016 Lisbon, Portugal
| | - Manuel Prieto
- IBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal; (L.B.-A.); (D.M.-H.); (N.B.); (A.C.); (M.P.)
- Associate Laboratory i4HB—Institute for Health and Bioeconomy at Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal
| | - Fábio Fernandes
- IBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal; (L.B.-A.); (D.M.-H.); (N.B.); (A.C.); (M.P.)
- Associate Laboratory i4HB—Institute for Health and Bioeconomy at Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal
- Department of Bioengineering, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal
| |
Collapse
|
10
|
Jeyasimman D, Ercan B, Dharmawan D, Naito T, Sun J, Saheki Y. PDZD-8 and TEX-2 regulate endosomal PI(4,5)P 2 homeostasis via lipid transport to promote embryogenesis in C. elegans. Nat Commun 2021; 12:6065. [PMID: 34663803 PMCID: PMC8523718 DOI: 10.1038/s41467-021-26177-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 09/22/2021] [Indexed: 11/10/2022] Open
Abstract
Different types of cellular membranes have unique lipid compositions that are important for their functional identity. PI(4,5)P2 is enriched in the plasma membrane where it contributes to local activation of key cellular events, including actomyosin contraction and cytokinesis. However, how cells prevent PI(4,5)P2 from accumulating in intracellular membrane compartments, despite constant intermixing and exchange of lipid membranes, is poorly understood. Using the C. elegans early embryo as our model system, we show that the evolutionarily conserved lipid transfer proteins, PDZD-8 and TEX-2, act together with the PI(4,5)P2 phosphatases, OCRL-1 and UNC-26/synaptojanin, to prevent the build-up of PI(4,5)P2 on endosomal membranes. In the absence of these four proteins, large amounts of PI(4,5)P2 accumulate on endosomes, leading to embryonic lethality due to ectopic recruitment of proteins involved in actomyosin contractility. PDZD-8 localizes to the endoplasmic reticulum and regulates endosomal PI(4,5)P2 levels via its lipid harboring SMP domain. Accumulation of PI(4,5)P2 on endosomes is accompanied by impairment of their degradative capacity. Thus, cells use multiple redundant systems to maintain endosomal PI(4,5)P2 homeostasis.
Collapse
Affiliation(s)
- Darshini Jeyasimman
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore
| | - Bilge Ercan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore
| | - Dennis Dharmawan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore
| | - Tomoki Naito
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore
| | - Jingbo Sun
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore
| | - Yasunori Saheki
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, 308232, Singapore.
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, 860-8556, Japan.
| |
Collapse
|
11
|
Wen Y, Vogt VM, Feigenson GW. PI(4,5)P 2 Clustering and Its Impact on Biological Functions. Annu Rev Biochem 2021; 90:681-707. [PMID: 33441034 DOI: 10.1146/annurev-biochem-070920-094827] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Located at the inner leaflet of the plasma membrane (PM), phosphatidyl-inositol 4,5-bisphosphate [PI(4,5)P2] composes only 1-2 mol% of total PM lipids. With its synthesis and turnover both spatially and temporally regulated, PI(4,5)P2 recruits and interacts with hundreds of cellular proteins to support a broad spectrum of cellular functions. Several factors contribute to the versatile and dynamic distribution of PI(4,5)P2 in membranes. Physiological multivalent cations such as Ca2+ and Mg2+ can bridge between PI(4,5)P2 headgroups, forming nanoscopic PI(4,5)P2-cation clusters. The distinct lipid environment surrounding PI(4,5)P2 affects the degree of PI(4,5)P2 clustering. In addition, diverse cellular proteins interacting with PI(4,5)P2 can further regulate PI(4,5)P2 lateral distribution and accessibility. This review summarizes the current understanding of PI(4,5)P2 behavior in both cells and model membranes, with emphasis on both multivalent cation- and protein-induced PI(4,5)P2 clustering. Understanding the nature of spatially separated pools of PI(4,5)P2 is fundamental to cell biology.
Collapse
Affiliation(s)
- Yi Wen
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA; , ,
| | - Volker M Vogt
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA; , ,
| | - Gerald W Feigenson
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14850, USA; , ,
| |
Collapse
|
12
|
Borges-Araújo L, Fernandes F. Structure and Lateral Organization of Phosphatidylinositol 4,5-bisphosphate. Molecules 2020; 25:molecules25173885. [PMID: 32858905 PMCID: PMC7503891 DOI: 10.3390/molecules25173885] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/22/2020] [Accepted: 08/23/2020] [Indexed: 02/07/2023] Open
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) is a minor but ubiquitous component of the inner leaflet of the plasma membrane of eukaryotic cells. However, due to its particular complex biophysical properties, it stands out from its neighboring lipids as one of the most important regulators of membrane-associated signaling events. Despite its very low steady-state concentration, PI(4,5)P2 is able to engage in a multitude of simultaneous cellular functions that are temporally and spatially regulated through the presence of localized transient pools of PI(4,5)P2 in the membrane. These pools are crucial for the recruitment, activation, and organization of signaling proteins and consequent regulation of downstream signaling. The present review showcases some of the most important PI(4,5)P2 molecular and biophysical properties as well as their impact on its membrane dynamics, lateral organization, and interactions with other biochemical partners.
Collapse
Affiliation(s)
- Luís Borges-Araújo
- iBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal;
- Correspondence:
| | - Fabio Fernandes
- iBB—Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal;
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisbon, Portugal
| |
Collapse
|
13
|
Ouweneel AB, Thomas MJ, Sorci-Thomas MG. The ins and outs of lipid rafts: functions in intracellular cholesterol homeostasis, microparticles, and cell membranes: Thematic Review Series: Biology of Lipid Rafts. J Lipid Res 2020; 61:676-686. [PMID: 33715815 PMCID: PMC7193959 DOI: 10.1194/jlr.tr119000383] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 12/17/2019] [Indexed: 12/12/2022] Open
Abstract
Cellular membranes are not homogenous mixtures of proteins; rather, they are segregated into microdomains on the basis of preferential association between specific lipids and proteins. These microdomains, called lipid rafts, are well known for their role in receptor signaling on the plasma membrane (PM) and are essential to such cellular functions as signal transduction and spatial organization of the PM. A number of disease states, including atherosclerosis and other cardiovascular disorders, may be caused by dysfunctional maintenance of lipid rafts. Lipid rafts do not occur only in the PM but also have been found in intracellular membranes and extracellular vesicles (EVs). Here, we focus on discussing newly discovered functions of lipid rafts and microdomains in intracellular membranes, including lipid and protein trafficking from the ER, Golgi bodies, and endosomes to the PM, and we examine lipid raft involvement in the production and composition of EVs. Because lipid rafts are small and transient, visualization remains challenging. Future work with advanced techniques will continue to expand our knowledge about the roles of lipid rafts in cellular functioning.
Collapse
Affiliation(s)
- Amber B Ouweneel
- Department of Medicine, Division of Endocrinology and Molecular Medicine,Medical College of Wisconsin, Milwaukee, WI 53226; Cardiovascular Center,Medical College of Wisconsin, Milwaukee, WI 53226
| | - Michael J Thomas
- Cardiovascular Center,Medical College of Wisconsin, Milwaukee, WI 53226; Department of Pharmacology and Toxicology,Medical College of Wisconsin, Milwaukee, WI 53226
| | - Mary G Sorci-Thomas
- Department of Medicine, Division of Endocrinology and Molecular Medicine,Medical College of Wisconsin, Milwaukee, WI 53226; Cardiovascular Center,Medical College of Wisconsin, Milwaukee, WI 53226; Department of Pharmacology and Toxicology,Medical College of Wisconsin, Milwaukee, WI 53226. mailto:
| |
Collapse
|
14
|
Zhai YJ, Wu MM, Linck VA, Zou L, Yue Q, Wei SP, Song C, Zhang S, Williams CR, Song BL, Zhang ZR, Ma HP. Intracellular cholesterol stimulates ENaC by interacting with phosphatidylinositol‑4,5‑bisphosphate and mediates cyclosporine A-induced hypertension. Biochim Biophys Acta Mol Basis Dis 2019; 1865:1915-1924. [PMID: 31109455 DOI: 10.1016/j.bbadis.2018.08.027] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Revised: 08/04/2018] [Accepted: 08/19/2018] [Indexed: 12/31/2022]
Abstract
We have previously shown that blockade of ATP-binding cassette transporter A1 (ABCA1) with cyclosporine A (CsA) stimulates the epithelial sodium channel (ENaC) in cultured distal nephron cells. Here we show that CsA elevated systolic blood pressure in both wild-type and apolipoprotein E (ApoE) knockout (KO) mice to a similar level. The elevated systolic blood pressure was completely reversed by inhibition of cholesterol (Cho) synthesis with lovastatin. Inside-out patch-clamp data show that intracellular Cho stimulated ENaC in cultured distal nephron cells by interacting with phosphatidylinositol‑4,5‑bisphosphate (PIP2), an ENaC activator. Confocal microscopy data show that both α‑ENaC and PIP2 were localized in microvilli via a Cho-dependent mechanism. Deletion of membrane Cho reduced the levels of γ‑ENaC in the apical membrane. Reduced ABCA1 expression and elevated intracellular Cho were observed in old mice, compared to young mice. In parallel, cell-attached patch-clamp data from the split-open cortical collecting ducts (CCD) show that ENaC activity was significantly increased in old mice. These data suggest that elevation of intracellular Cho due to blockade of ABCA1 stimulates ENaC, which may contribute to CsA-induced hypertension. This study also implies that reduced ABCA1 expression may mediate age-related hypertension by increasing ENaC activity via elevation of intracellular Cho.
Collapse
Affiliation(s)
- Yu-Jia Zhai
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Ming-Ming Wu
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Cardiology, Clinic Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin 150081, China
| | - Valerie A Linck
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Li Zou
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Qiang Yue
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Shi-Peng Wei
- Department of Internal Medicine, Medical College of Georgia at Augusta University, Augusta, GA 30912, USA
| | - Chang Song
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Shuai Zhang
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Clintoria R Williams
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Bin-Lin Song
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Cardiology, Clinic Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin 150081, China
| | - Zhi-Ren Zhang
- Department of Cardiology, Clinic Pharmacy, Harbin Medical University Cancer Hospital, Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin 150081, China.
| | - He-Ping Ma
- Department of Physiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| |
Collapse
|
15
|
Multivalent Cation-Bridged PI(4,5)P 2 Clusters Form at Very Low Concentrations. Biophys J 2019; 114:2630-2639. [PMID: 29874613 DOI: 10.1016/j.bpj.2018.04.048] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 03/27/2018] [Accepted: 04/10/2018] [Indexed: 01/09/2023] Open
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2 or PIP2), is a key component of the inner leaflet of the plasma membrane in eukaryotic cells. In model membranes, PIP2 has been reported to form clusters, but whether these locally different conditions could give rise to distinct pools of unclustered and clustered PIP2 is unclear. By use of both fluorescence self-quenching and Förster resonance energy transfer assays, we have discovered that PIP2 self-associates at remarkably low concentrations starting below 0.05 mol% of total lipids. Formation of these clusters was dependent on physiological divalent metal ions, such as Ca2+, Mg2+, Zn2+, or trivalent ions Fe3+ and Al3+. Formation of PIP2 clusters was also headgroup-specific, being largely independent of the type of acyl chain. The similarly labeled phospholipids phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, and phosphatidylinositol exhibited no such clustering. However, six phosphoinositide species coclustered with PIP2. The degree of PIP2 cation clustering was significantly influenced by the composition of the surrounding lipids, with cholesterol and phosphatidylinositol enhancing this behavior. We propose that PIP2 cation-bridged cluster formation, which might be similar to micelle formation, can be used as a physical model for what could be distinct pools of PIP2 in biological membranes. To our knowledge, this study provides the first evidence of PIP2 forming clusters at such low concentrations. The property of PIP2 to form such clusters at such extremely low concentrations in model membranes reveals, to our knowledge, a new behavior of PIP2 proposed to occur in cells, in which local multivalent metal ions, lipid compositions, and various binding proteins could greatly influence PIP2 properties. In turn, these different pools of PIP2 could further regulate cellular events.
Collapse
|
16
|
Molecular Dynamics of the Association of L-Selectin and FERM Regulated by PIP2. Biophys J 2019; 114:1858-1868. [PMID: 29694864 DOI: 10.1016/j.bpj.2018.02.034] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 02/05/2018] [Accepted: 02/20/2018] [Indexed: 11/22/2022] Open
Abstract
Phosphatidylinositol 4,5-bisphosphate (PIP2) acts as a signaling lipid, mediating membrane trafficking and recruitment of proteins to membranes. A key example is the PIP2-dependent regulation of the adhesion of L-selectin to the cytoskeleton adaptors of the N-terminal subdomain of ezrin-radixin-moesin (FERM). The molecular details of the mediating behavior of multivalent anionic PIP2 lipids in this process, however, remain unclear. Here, we use coarse-grained molecular dynamics simulation to explore the mechanistic details of PIP2 in the transformation, translocation, and association of the FERM/L-selectin complex. We compare membranes of different compositions and find that anionic phospholipids are necessary for both FERM and the cytoplasmic domain of L-selectin to absorb on the membrane surface. The subsequent formation of the FERM/L-selectin complex is strongly favored by the presence of PIP2, which clusters around both proteins and triggers a conformational transition in the cytoplasmic domain of L-selectin. We are able to quantify the effect of PIP2 on the association free energy of the complex by means of a potential of mean force. We conclude that PIP2 behaves as an adhesive agent to enhance the stability of the FERM/L-selectin complex and identify key residues involved. The molecular information revealed in this study highlights the specific role of membrane lipids such as PIP2 in protein translocation and potential signaling.
Collapse
|
17
|
Vu LD, Gevaert K, De Smet I. Feeling the Heat: Searching for Plant Thermosensors. TRENDS IN PLANT SCIENCE 2019; 24:210-219. [PMID: 30573309 DOI: 10.1016/j.tplants.2018.11.004] [Citation(s) in RCA: 67] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 11/15/2018] [Accepted: 11/19/2018] [Indexed: 05/21/2023]
Abstract
To draw the complete picture of plant thermal signaling, it is important to find the missing links between the temperature cue, the actual sensing, and the subsequent response. In this context, several plant thermosensors have been proposed. Here, we compare these with thermosensors in various other organisms, put them in the context of thermosensing in plants, and suggest a set of criteria to which a thermosensor must adhere. Finally, we propose that more emphasis should be given to structural analysis of DNA, RNA, and proteins in light of the activity of potential thermosensors.
Collapse
Affiliation(s)
- Lam Dai Vu
- Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium; VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium; Department of Biomolecular Medicine, Ghent University, B-9000 Ghent, Belgium; VIB Center for Medical Biotechnology, B-9000 Ghent, Belgium
| | - Kris Gevaert
- Department of Biomolecular Medicine, Ghent University, B-9000 Ghent, Belgium; VIB Center for Medical Biotechnology, B-9000 Ghent, Belgium; These authors contributed equally. https://twitter.com/KrisGevaert_VIB
| | - Ive De Smet
- Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium; VIB Center for Plant Systems Biology, B-9052 Ghent, Belgium; These authors contributed equally.
| |
Collapse
|
18
|
Taylor J, Bebawy M. Proteins Regulating Microvesicle Biogenesis and Multidrug Resistance in Cancer. Proteomics 2019; 19:e1800165. [PMID: 30520565 DOI: 10.1002/pmic.201800165] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 12/02/2018] [Indexed: 01/01/2023]
Abstract
Microvesicles (MV) are emerging as important mediators of intercellular communication. While MVs are important signaling vectors for many physiological processes, they are also implicated in cancer pathology and progression. Cellular activation is perhaps the most widely reported initiator of MV biogenesis, however, the precise mechanism remains undefined. Uncovering the proteins involved in regulating MV biogenesis is of interest given their role in the dissemination of deleterious cancer traits. MVs shed from drug-resistant cancer cells transfer multidrug resistance (MDR) proteins to drug-sensitive cells and confer the MDR phenotype in a matter of hours. MDR is attributed to the overexpression of ABC transporters, primarily P-glycoprotein and MRP1. Their expression and functionality is dependent on a number of proteins. In particular, FERM domain proteins have been implicated in supporting the functionality of efflux transporters in drug-resistant cells and in recipient cells during intercellular transfer by vesicles. Herein, the most recent research on the proteins involved in MV biogenesis and in the dissemination of MV-mediated MDR are discussed. Attention is drawn to unanswered questions in the literature that may prove to be of benefit in ongoing efforts to improve clinical response to chemotherapy and circumventing MDR.
Collapse
Affiliation(s)
- Jack Taylor
- Discipline of Pharmacy, Graduate School of Health, The University of Technology Sydney, Sydney, Australia
| | - Mary Bebawy
- Discipline of Pharmacy, Graduate School of Health, The University of Technology Sydney, Sydney, Australia
| |
Collapse
|
19
|
Bieberich E. Sphingolipids and lipid rafts: Novel concepts and methods of analysis. Chem Phys Lipids 2018; 216:114-131. [PMID: 30194926 PMCID: PMC6196108 DOI: 10.1016/j.chemphyslip.2018.08.003] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/20/2018] [Accepted: 08/25/2018] [Indexed: 12/12/2022]
Abstract
About twenty years ago, the functional lipid raft model of the plasma membrane was published. It took into account decades of research showing that cellular membranes are not just homogenous mixtures of lipids and proteins. Lateral anisotropy leads to assembly of membrane domains with specific lipid and protein composition regulating vesicular traffic, cell polarity, and cell signaling pathways in a plethora of biological processes. However, what appeared to be a clearly defined entity of clustered raft lipids and proteins became increasingly fluid over the years, and many of the fundamental questions about biogenesis and structure of lipid rafts remained unanswered. Experimental obstacles in visualizing lipids and their interactions hampered progress in understanding just how big rafts are, where and when they are formed, and with which proteins raft lipids interact. In recent years, we have begun to answer some of these questions and sphingolipids may take center stage in re-defining the meaning and functional significance of lipid rafts. In addition to the archetypical cholesterol-sphingomyelin raft with liquid ordered (Lo) phase and the liquid-disordered (Ld) non-raft regions of cellular membranes, a third type of microdomains termed ceramide-rich platforms (CRPs) with gel-like structure has been identified. CRPs are "ceramide rafts" that may offer some fresh view on the membrane mesostructure and answer several critical questions for our understanding of lipid rafts.
Collapse
Affiliation(s)
- Erhard Bieberich
- Department of Physiology at the University of Kentucky, Lexington, KY, United States.
| |
Collapse
|
20
|
Trinconi CT, Miguel DC, Silber AM, Brown C, Mina JGM, Denny PW, Heise N, Uliana SRB. Tamoxifen inhibits the biosynthesis of inositolphosphorylceramide in Leishmania. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2018; 8:475-487. [PMID: 30399513 PMCID: PMC6216108 DOI: 10.1016/j.ijpddr.2018.10.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 09/21/2018] [Accepted: 10/23/2018] [Indexed: 11/19/2022]
Abstract
Previous work from our group showed that tamoxifen, an oral drug that has been in use for the treatment of breast cancer for over 40 years, is active both in vitro and in vivo against several species of Leishmania, the etiological agent of leishmaniasis. Using a combination of metabolic labeling with [3H]-sphingosine and myo-[3H]-inositol, alkaline hydrolysis, HPTLC fractionations and mass spectrometry analyses, we observed a perturbation in the metabolism of inositolphosphorylceramides (IPCs) and phosphatidylinositols (PIs) after treatment of L. amazonensis promastigotes with tamoxifen, with a significant reduction in the biosynthesis of the major IPCs (composed of d16:1/18:0-IPC, t16:0/C18:0-IPC, d18:1/18:0-IPC and t16:0/20:0-IPC) and PIs (sn-1-O-(C18:0)alkyl -2-O-(C18:1)acylglycerol-3-HPO4-inositol and sn-1-O-(C18:0)acyl-2-O-(C18:1)acylglycerol-3-HPO4-inositol) species. Substrate saturation kinetics of myo-inositol uptake analyses indicated that inhibition of inositol transport or availability were not the main reasons for the reduced biosynthesis of IPC and PI observed in tamoxifen treated parasites. An in vitro enzymatic assay was used to show that tamoxifen was able to inhibit the Leishmania IPC synthase with an IC50 value of 8.48 μM (95% CI 7.68–9.37), suggesting that this enzyme is most likely one of the targets for this compound in the parasites. Tamoxifen alters the sphingolipid metabolism of L. amazonensis. Tamoxifen treated parasites show a significant reduction of IPC and PI species. Tamoxifen-treated parasites present a reduction of inositol transport. Tamoxifen is an inhibitor of L. major's IPC synthase in a micromolar range.
Collapse
Affiliation(s)
- Cristiana T Trinconi
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-000, Brazil
| | - Danilo C Miguel
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-000, Brazil
| | - Ariel M Silber
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-000, Brazil
| | - Christopher Brown
- Department of Biosciences, Durham University, Stockton Road, Durham, DH1 3LE, UK
| | - John G M Mina
- Department of Biosciences, Durham University, Stockton Road, Durham, DH1 3LE, UK
| | - Paul W Denny
- Department of Biosciences, Durham University, Stockton Road, Durham, DH1 3LE, UK
| | - Norton Heise
- Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Av. Carlos Chagas Filho, 373, Rio de Janeiro, RJ, 21941-902, Brazil
| | - Silvia R B Uliana
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes, 1374, São Paulo, SP, 05508-000, Brazil.
| |
Collapse
|
21
|
Beber A, Alqabandi M, Prévost C, Viars F, Lévy D, Bassereau P, Bertin A, Mangenot S. Septin‐based readout of PI(4,5)P2 incorporation into membranes of giant unilamellar vesicles. Cytoskeleton (Hoboken) 2018; 76:92-103. [DOI: 10.1002/cm.21480] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 07/05/2018] [Accepted: 07/10/2018] [Indexed: 01/27/2023]
Affiliation(s)
- Alexandre Beber
- Laboratoire Physico Chimie CurieInstitut Curie, PSL Research University Paris France
- Sorbonne Université Paris France
| | - Maryam Alqabandi
- Laboratoire Physico Chimie CurieInstitut Curie, PSL Research University Paris France
- Sorbonne Université Paris France
| | - Coline Prévost
- Laboratoire Physico Chimie CurieInstitut Curie, PSL Research University Paris France
- Sorbonne Université Paris France
| | - Fanny Viars
- Institut des maladies métaboliques et cardiovasculairesUMR1048, Inserm/Université Paul Sabatier Toulouse France
| | - Daniel Lévy
- Laboratoire Physico Chimie CurieInstitut Curie, PSL Research University Paris France
- Sorbonne Université Paris France
| | - Patricia Bassereau
- Laboratoire Physico Chimie CurieInstitut Curie, PSL Research University Paris France
- Sorbonne Université Paris France
| | - Aurélie Bertin
- Laboratoire Physico Chimie CurieInstitut Curie, PSL Research University Paris France
- Sorbonne Université Paris France
| | - Stéphanie Mangenot
- Laboratoire Physico Chimie CurieInstitut Curie, PSL Research University Paris France
- Sorbonne Université Paris France
| |
Collapse
|
22
|
Vesicle Docking Is a Key Target of Local PI(4,5)P 2 Metabolism in the Secretory Pathway of INS-1 Cells. Cell Rep 2018; 20:1409-1421. [PMID: 28793264 PMCID: PMC5613661 DOI: 10.1016/j.celrep.2017.07.041] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 05/31/2017] [Accepted: 07/14/2017] [Indexed: 12/29/2022] Open
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) signaling is transient and spatially confined in live cells. How this pattern of signaling regulates transmitter release and hormone secretion has not been addressed. We devised an optogenetic approach to control PI(4,5)P2 levels in time and space in insulin-secreting cells. Combining this approach with total internal reflection fluorescence microscopy, we examined individual vesicle-trafficking steps. Unlike long-term PI(4,5)P2 perturbations, rapid and cell-wide PI(4,5)P2 reduction in the plasma membrane (PM) strongly inhibits secretion and intracellular Ca2+ concentration ([Ca2+]i) responses, but not sytaxin1a clustering. Interestingly, local PI(4,5)P2 reduction selectively at vesicle docking sites causes remarkable vesicle undocking from the PM without affecting [Ca2+]i. These results highlight a key role of local PI(4,5)P2 in vesicle tethering and docking, coordinated with its role in priming and fusion. Thus, different spatiotemporal PI(4,5)P2 signaling regulates distinct steps of vesicle trafficking, and vesicle docking may be a key target of local PI(4,5)P2 signaling in vivo.
Collapse
|
23
|
Yoo SM, Cerione RA, Antonyak MA. The Arf-GAP and protein scaffold Cat1/Git1 as a multifaceted regulator of cancer progression. Small GTPases 2017; 11:77-85. [PMID: 28981399 DOI: 10.1080/21541248.2017.1362496] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Cool-associated tyrosine phosphorylated protein 1 (Cat1), also referred to as GPCR-kinase interacting protein 1 (Git1), is a ubiquitously expressed, multi-domain protein that is best known for regulating cell shape and migration. Cat1/Git1 functions as a GTPase activating protein (GAP) that inactivates certain members of the ADP-ribosylation factor (Arf) family of small GTPases. It is also a scaffold that brings together several signaling proteins at specific locations within the cell, ensuring their efficient activation. Here we will discuss what is known regarding the classical role of Cat1/Git1 in the regulation of cell morphology and migration, as well as highlight some more recent findings that suggest this interesting signaling/scaffolding protein may also contribute in unexpected ways to oncogenic transformation.
Collapse
Affiliation(s)
- Sungsoo M Yoo
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Richard A Cerione
- Department of Molecular Medicine, Cornell University, Ithaca, NY, USA.,Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA
| | - Marc A Antonyak
- Department of Molecular Medicine, Cornell University, Ithaca, NY, USA
| |
Collapse
|
24
|
Ren H, Gao K, Liu Y, Sun D, Zheng S. The role of AtPLC3 and AtPLC9 in thermotolerance in Arabidopsis. PLANT SIGNALING & BEHAVIOR 2017; 12:e1162368. [PMID: 27070271 PMCID: PMC5647968 DOI: 10.1080/15592324.2016.1162368] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 02/29/2016] [Accepted: 03/01/2016] [Indexed: 05/19/2023]
Abstract
Plants respond and adapt to temperature changes by many ways. In this article, we provide a supplement to previous work about AtPLC3. The subcellular localization showed that AtPLC3 was located in the plasma membrane and nucleus which differed from AtPLC9 localization. Furthermore, we measured the contents of IP3 before and after HS in AtPLC3 mutant, complemented and overexpressing lines. The results showed that the increase in IP3 after HS was partially dependent on AtPLC3 activity. To sum up, the similar expression patterns and phenotypes suggested that AtPLC3 and AtPLC9 may regulate the thermotolerance of Arabidopsis by the same mechanisms.
Collapse
Affiliation(s)
- Huimin Ren
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijiazhuang, China
| | - Kang Gao
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijiazhuang, China
| | - Yuliang Liu
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijiazhuang, China
| | - Daye Sun
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijiazhuang, China
| | - Shuzhi Zheng
- Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Science, Hebei Normal University, Shijiazhuang, China
| |
Collapse
|
25
|
Biesemann A, Gorontzi A, Barr F, Gerke V. Rab35 protein regulates evoked exocytosis of endothelial Weibel-Palade bodies. J Biol Chem 2017; 292:11631-11640. [PMID: 28566286 PMCID: PMC5512060 DOI: 10.1074/jbc.m116.773333] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 05/15/2017] [Indexed: 12/22/2022] Open
Abstract
Weibel–Palade bodies (WPB) are secretory organelles of endothelial cells that undergo evoked exocytosis following intracellular Ca2+ or cAMP elevation, thereby supplying the vasculature with factors controlling hemostasis. Several cytosolic and membrane-associated proteins, including the Rab family members Rab3, Rab15, and Rab27a, have been implicated in regulating the acute exocytosis of WPB. Here, we carried out a genome-wide screen to identify Rab pathways affecting WPB exocytosis. Overexpression of a specific subset of Rab GTPase–activating proteins (RabGAPs) inhibited histamine-evoked, Ca2+-dependent WPB exocytosis, presumably by inactivating the target Rab GTPases. Among these RabGAPs, we concentrated on TBC1D10A and showed that the inhibitory effect depends on its GAP activity. We confirmed that Rab35 was a target Rab of TBC1D10A in human endothelial cells; Rab35 interacted with TBC1D10A, and expression of the GAP-insensitive Rab35(Q67A) mutant rescued the inhibitory effect of TBC1D10A overexpression on WPB exocytosis. Furthermore, knockdown of Rab35 and expression of a dominant-negative Rab35 mutant both inhibited histamine-evoked secretion of the WPB cargos von Willebrand factor and P-selectin. Pulldown and co-immunoprecipitation experiments identified the ArfGAP with coiled-coil, Ank repeat, and pleckstrin homology domain–containing protein ACAP2 as an Rab35 effector in endothelial cells, and depletion as well as overexpression approaches revealed that ACAP2 acts as a negative regulator of WPB exocytosis. Interestingly, a known ACAP2 target, the small GTPase Arf6, supported histamine-evoked WPB exocytosis, as shown by knockdown and overexpression of a dominant-negative Arf6 mutant. Our data identify Rab35 as a novel regulator of WPB exocytosis, most likely acting through the downstream effectors ACAP2 and Arf6.
Collapse
Affiliation(s)
- Anja Biesemann
- Institute of Medical Biochemistry, Center for Molecular Biology of Inflammation, University of Münster, D-48149 Münster, Germany
| | - Alexandra Gorontzi
- Institute of Medical Biochemistry, Center for Molecular Biology of Inflammation, University of Münster, D-48149 Münster, Germany
| | - Francis Barr
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Volker Gerke
- Institute of Medical Biochemistry, Center for Molecular Biology of Inflammation, University of Münster, D-48149 Münster, Germany.
| |
Collapse
|
26
|
Harding T, Roger AJ, Simpson AGB. Adaptations to High Salt in a Halophilic Protist: Differential Expression and Gene Acquisitions through Duplications and Gene Transfers. Front Microbiol 2017; 8:944. [PMID: 28611746 PMCID: PMC5447177 DOI: 10.3389/fmicb.2017.00944] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 05/11/2017] [Indexed: 11/13/2022] Open
Abstract
The capacity of halophiles to thrive in extreme hypersaline habitats derives partly from the tight regulation of ion homeostasis, the salt-dependent adjustment of plasma membrane fluidity, and the increased capability to manage oxidative stress. Halophilic bacteria, and archaea have been intensively studied, and substantial research has been conducted on halophilic fungi, and the green alga Dunaliella. By contrast, there have been very few investigations of halophiles that are phagotrophic protists, i.e., protozoa. To gather fundamental knowledge about salt adaptation in these organisms, we studied the transcriptome-level response of Halocafeteria seosinensis (Stramenopiles) grown under contrasting salinities. We provided further evolutionary context to our analysis by identifying genes that underwent recent duplications. Genes that were highly responsive to salinity variations were involved in stress response (e.g., chaperones), ion homeostasis (e.g., Na+/H+ transporter), metabolism and transport of lipids (e.g., sterol biosynthetic genes), carbohydrate metabolism (e.g., glycosidases), and signal transduction pathways (e.g., transcription factors). A significantly high proportion (43%) of duplicated genes were also differentially expressed, accentuating the importance of gene expansion in adaptation by H. seosinensis to high salt environments. Furthermore, we found two genes that were lateral acquisitions from bacteria, and were also highly up-regulated and highly expressed at high salt, suggesting that this evolutionary mechanism could also have facilitated adaptation to high salt. We propose that a transition toward high-salt adaptation in the ancestors of H. seosinensis required the acquisition of new genes via duplication, and some lateral gene transfers (LGTs), as well as the alteration of transcriptional programs, leading to increased stress resistance, proper establishment of ion gradients, and modification of cell structure properties like membrane fluidity.
Collapse
Affiliation(s)
- Tommy Harding
- Department of Biochemistry and Molecular Biology, Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie UniversityHalifax, NS, Canada
| | - Andrew J. Roger
- Department of Biochemistry and Molecular Biology, Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie UniversityHalifax, NS, Canada
| | - Alastair G. B. Simpson
- Department of Biology and Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie UniversityHalifax, NS, Canada
| |
Collapse
|
27
|
Wiessner M, Roos A, Munn CJ, Viswanathan R, Whyte T, Cox D, Schoser B, Sewry C, Roper H, Phadke R, Marini Bettolo C, Barresi R, Charlton R, Bönnemann CG, Abath Neto O, Reed UC, Zanoteli E, Araújo Martins Moreno C, Ertl-Wagner B, Stucka R, De Goede C, Borges da Silva T, Hathazi D, Dell’Aica M, Zahedi RP, Thiele S, Müller J, Kingston H, Müller S, Curtis E, Walter MC, Strom TM, Straub V, Bushby K, Muntoni F, Swan LE, Lochmüller H, Senderek J. Mutations in INPP5K, Encoding a Phosphoinositide 5-Phosphatase, Cause Congenital Muscular Dystrophy with Cataracts and Mild Cognitive Impairment. Am J Hum Genet 2017; 100:523-536. [PMID: 28190456 PMCID: PMC5339217 DOI: 10.1016/j.ajhg.2017.01.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 01/12/2017] [Indexed: 12/26/2022] Open
Abstract
Phosphoinositides are small phospholipids that control diverse cellular downstream signaling events. Their spatial and temporal availability is tightly regulated by a set of specific lipid kinases and phosphatases. Congenital muscular dystrophies are hereditary disorders characterized by hypotonia and weakness from birth with variable eye and central nervous system involvement. In individuals exhibiting congenital muscular dystrophy, early-onset cataracts, and mild intellectual disability but normal cranial magnetic resonance imaging, we identified bi-allelic mutations in INPP5K, encoding inositol polyphosphate-5-phosphatase K. Mutations impaired phosphatase activity toward the phosphoinositide phosphatidylinositol (4,5)-bisphosphate or altered the subcellular localization of INPP5K. Downregulation of INPP5K orthologs in zebrafish embryos disrupted muscle fiber morphology and resulted in abnormal eye development. These data link congenital muscular dystrophies to defective phosphoinositide 5-phosphatase activity that is becoming increasingly recognized for its role in mediating pivotal cellular mechanisms contributing to disease.
Collapse
|
28
|
Tanabe K. Image-based compound profiling reveals a dual inhibitor of tyrosine kinase and microtubule polymerization. Sci Rep 2016; 6:25095. [PMID: 27117592 PMCID: PMC4846875 DOI: 10.1038/srep25095] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Accepted: 04/11/2016] [Indexed: 12/31/2022] Open
Abstract
Small-molecule compounds are widely used as biological research tools and therapeutic drugs. Therefore, uncovering novel targets of these compounds should provide insights that are valuable in both basic and clinical studies. I developed a method for image-based compound profiling by quantitating the effects of compounds on signal transduction and vesicle trafficking of epidermal growth factor receptor (EGFR). Using six signal transduction molecules and two markers of vesicle trafficking, 570 image features were obtained and subjected to multivariate analysis. Fourteen compounds that affected EGFR or its pathways were classified into four clusters, based on their phenotypic features. Surprisingly, one EGFR inhibitor (CAS 879127-07-8) was classified into the same cluster as nocodazole, a microtubule depolymerizer. In fact, this compound directly depolymerized microtubules. These results indicate that CAS 879127-07-8 could be used as a chemical probe to investigate both the EGFR pathway and microtubule dynamics. The image-based multivariate analysis developed herein has potential as a powerful tool for discovering unexpected drug properties.
Collapse
Affiliation(s)
- Kenji Tanabe
- Medical Research Institute, Tokyo Women’s Medical University, Tokyo 162-8666, Japan
| |
Collapse
|
29
|
Murate M, Kobayashi T. Revisiting transbilayer distribution of lipids in the plasma membrane. Chem Phys Lipids 2016; 194:58-71. [DOI: 10.1016/j.chemphyslip.2015.08.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/14/2015] [Accepted: 08/17/2015] [Indexed: 12/22/2022]
|
30
|
Piscatelli HL, Li M, Zhou D. Dual 4- and 5-phosphatase activities regulate SopB-dependent phosphoinositide dynamics to promote bacterial entry. Cell Microbiol 2015; 18:705-19. [PMID: 26537021 DOI: 10.1111/cmi.12542] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 10/21/2015] [Accepted: 10/24/2015] [Indexed: 12/16/2022]
Abstract
Salmonella are able to invade non-phagocytic cells such as intestinal epithelial cells by modulating the host actin cytoskeleton to produce membrane ruffles. Two type III effector proteins SopB and SopE play key roles to this modulation. SopE is a known guanine nucleotide exchange factor (GEF) capable of activating Rac1 and CDC42. SopB is a phosphatidylinositol 4-phosphatase and 5-phosphatase promoting membrane ruffles and invasion of Salmonella through undefined mechanisms. Previous studies have demonstrated that the 4-phosphatase activity of SopB is required for PtdIns-3-phosphate (PtdIns(3)P) accumulation and SopB-mediated invasion. We show here that both the 4-phosphatase as well as the 5-phosphatase activities of SopB are essential in ruffle formation and subsequent invasion. We found that the 5-phosphatase activity of SopB is likely responsible for generating PtdIns-3,4-bisphosphate (PtdIns(3,4)P(2)) and subsequent recruitment of sorting nexin 9 (SNX9), an actin modulating protein. Intriguingly, the 4-phosphatase activity is responsible for the dephosphorylation of PtdIns(3,4)P(2) into PtdIns(3)P. Alone, neither activity is sufficient for ruffling but when acting in conjunction with one another, the 4-phosphatase and 5-phosphatase activities led to SNX9-mediated ruffling and Salmonella invasion. This work reveals the unique ability of bacterial effector protein SopB to utilize both its 4- and 5-phosphatase activities to regulate phosphoinositide dynamics to promote bacterial entry.
Collapse
Affiliation(s)
- Heather L Piscatelli
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Menghan Li
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| | - Daoguo Zhou
- Department of Biological Sciences, Purdue University, West Lafayette, IN, 47907, USA
| |
Collapse
|
31
|
Sengelaub CA, Navrazhina K, Ross JB, Halberg N, Tavazoie SF. PTPRN2 and PLCβ1 promote metastatic breast cancer cell migration through PI(4,5)P2-dependent actin remodeling. EMBO J 2015; 35:62-76. [PMID: 26620550 PMCID: PMC4717998 DOI: 10.15252/embj.201591973] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 10/19/2015] [Indexed: 12/22/2022] Open
Abstract
Altered abundance of phosphatidyl inositides (PIs) is a feature of cancer. Various PIs mark the identity of diverse membranes in normal and malignant cells. Phosphatidylinositol 4,5‐bisphosphate (PI(4,5)P2) resides predominantly in the plasma membrane, where it regulates cellular processes by recruiting, activating, or inhibiting proteins at the plasma membrane. We find that PTPRN2 and PLCβ1 enzymatically reduce plasma membrane PI(4,5)P2 levels in metastatic breast cancer cells through two independent mechanisms. These genes are upregulated in highly metastatic breast cancer cells, and their increased expression associates with human metastatic relapse. Reduction in plasma membrane PI(4,5)P2 abundance by these enzymes releases the PI(4,5)P2‐binding protein cofilin from its inactive membrane‐associated state into the cytoplasm where it mediates actin turnover dynamics, thereby enhancing cellular migration and metastatic capacity. Our findings reveal an enzymatic network that regulates metastatic cell migration through lipid‐dependent sequestration of an actin‐remodeling factor.
Collapse
Affiliation(s)
- Caitlin A Sengelaub
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY, USA
| | - Kristina Navrazhina
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY, USA
| | - Jason B Ross
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY, USA
| | - Nils Halberg
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY, USA
| | - Sohail F Tavazoie
- Laboratory of Systems Cancer Biology, Rockefeller University, New York, NY, USA
| |
Collapse
|
32
|
Tan X, Thapa N, Choi S, Anderson RA. Emerging roles of PtdIns(4,5)P2--beyond the plasma membrane. J Cell Sci 2015; 128:4047-56. [PMID: 26574506 PMCID: PMC4712784 DOI: 10.1242/jcs.175208] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Phosphoinositides are a collection of lipid messengers that regulate most subcellular processes. Amongst the seven phosphoinositide species, the roles for phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2] at the plasma membrane, such as in endocytosis, exocytosis, actin polymerization and focal adhesion assembly, have been extensively studied. Recent studies have argued for the existence of PtdIns(4,5)P2 at multiple intracellular compartments, including the nucleus, endosomes, lysosomes, autolysosomes, autophagic precursor membranes, ER, mitochondria and the Golgi complex. Although the generation, regulation and functions of PtdIns(4,5)P2 are less well-defined in most other intracellular compartments, accumulating evidence demonstrates crucial roles for PtdIns(4,5)P2 in endolysosomal trafficking, endosomal recycling, as well as autophagosomal pathways, which are the focus of this Commentary. We summarize and discuss how phosphatidylinositol phosphate kinases, PtdIns(4,5)P2 and PtdIns(4,5)P2-effectors regulate these intracellular protein and membrane trafficking events.
Collapse
Affiliation(s)
- Xiaojun Tan
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Narendra Thapa
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Suyong Choi
- Program in Cellular and Molecular Biology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Richard A Anderson
- Program in Molecular and Cellular Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA Program in Cellular and Molecular Biology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| |
Collapse
|
33
|
PIP2Clustering: From model membranes to cells. Chem Phys Lipids 2015; 192:33-40. [DOI: 10.1016/j.chemphyslip.2015.07.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2015] [Revised: 07/26/2015] [Accepted: 07/27/2015] [Indexed: 11/23/2022]
|
34
|
Wang C, Wu X, Shen F, Li Y, Zhang Y, Yu D. Shlnc-EC6 regulates murine erythroid enucleation by Rac1-PIP5K pathway. Dev Growth Differ 2015; 57:466-473. [PMID: 26098172 DOI: 10.1111/dgd.12225] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 04/15/2015] [Accepted: 05/03/2015] [Indexed: 12/20/2022]
Abstract
Long noncoding RNAs (LncRNAs) are longer than 200 nucleotide noncoding RNAs without apparent functional coding capacity that function as regulators of cell growth and development. In recent years, increasing evidence implicates the involvement of LncRNAs in erythropoiesis. shlnc-EC6 is a LncRNA associated with erythroid differentiation but the mechanism remains undefined. In this study, we found that knockdown of shlnc-EC6 in purified mouse fetal liver erythroid progenitor and hematopoietic stem cells (FLEPHSCs) significantly blocked erythroid enucleation. We also showed that Rac1 was negatively regulated by shlnc-EC6 at the posttranscriptional level via specific binding to sites within the 3'UTR of Rac1 mRNA. Moreover, we found that knockdown of shlnc-EC6 led to upregulation of Rac1, followed by the activation of the downstream protein PIP5K, and subsequently resulted in the inhibition of enucleation in cultured mouse fetal erythroblasts. Thus, our findings suggest that shlnc-EC6 acts as a novel modulator to regulate mouse erythropoiesis via Rac1/PIP5K signaling pathway.
Collapse
Affiliation(s)
- Chenghai Wang
- Non-coding RNA Center, Yangzhou University, 11 Huaihai Road, Yangzhou, 225001, China
| | - Xiaohui Wu
- Non-coding RNA Center, Yangzhou University, 11 Huaihai Road, Yangzhou, 225001, China
- Department of Pediatrics, Yangzhou University Affiliated Jingjiang Hospital, Jingjiang, 214500, China
| | - Feiyang Shen
- Non-coding RNA Center, Yangzhou University, 11 Huaihai Road, Yangzhou, 225001, China
| | - Yaoyao Li
- Non-coding RNA Center, Yangzhou University, 11 Huaihai Road, Yangzhou, 225001, China
| | - Yanqing Zhang
- Non-coding RNA Center, Yangzhou University, 11 Huaihai Road, Yangzhou, 225001, China
- Department of Pathology, Yangzhou University School of Medicine, 11 Huaihai Road, Yangzhou, 225001, China
| | - Duonan Yu
- Non-coding RNA Center, Yangzhou University, 11 Huaihai Road, Yangzhou, 225001, China
- Department of Physiology, Yangzhou University School of Medicine, 11 Huaihai Road, Yangzhou, 225001, China
- Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Disease, 11 Huaihai Road, Yangzhou, 225001, China
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Disease and Zoonoses, 11 Huaihai Road, Yangzhou, 225001, China
| |
Collapse
|
35
|
Brown LA, Cox C, Baptiste J, Summers H, Button R, Bahlow K, Spurrier V, Kyser J, Luttge BG, Kuo L, Freed EO, Summers MF. NMR structure of the myristylated feline immunodeficiency virus matrix protein. Viruses 2015; 7:2210-29. [PMID: 25941825 PMCID: PMC4452903 DOI: 10.3390/v7052210] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 03/30/2015] [Accepted: 04/21/2015] [Indexed: 11/25/2022] Open
Abstract
Membrane targeting by the Gag proteins of the human immunodeficiency viruses (HIV types-1 and -2) is mediated by Gag's N-terminally myristylated matrix (MA) domain and is dependent on cellular phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2]. To determine if other lentiviruses employ a similar membrane targeting mechanism, we initiated studies of the feline immunodeficiency virus (FIV), a widespread feline pathogen with potential utility for development of human therapeutics. Bacterial co-translational myristylation was facilitated by mutation of two amino acids near the amino-terminus of the protein (Q5A/G6S; myrMAQ5A/G6S). These substitutions did not affect virus assembly or release from transfected cells. NMR studies revealed that the myristyl group is buried within a hydrophobic pocket in a manner that is structurally similar to that observed for the myristylated HIV-1 protein. Comparisons with a recent crystal structure of the unmyristylated FIV protein [myr(-)MA] indicate that only small changes in helix orientation are required to accommodate the sequestered myr group. Depletion of PI(4,5)P2 from the plasma membrane of FIV-infected CRFK cells inhibited production of FIV particles, indicating that, like HIV, FIV hijacks the PI(4,5)P2 cellular signaling system to direct intracellular Gag trafficking during virus assembly.
Collapse
Affiliation(s)
- Lola A Brown
- Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
| | - Cassiah Cox
- Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
| | - Janae Baptiste
- Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
| | - Holly Summers
- Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
| | - Ryan Button
- Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
| | - Kennedy Bahlow
- Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
| | - Vaughn Spurrier
- Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
| | - Jenna Kyser
- Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
| | - Benjamin G Luttge
- Virus-Cell Interaction Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, Frederick, MD 21702-1201, USA.
| | - Lillian Kuo
- Virus-Cell Interaction Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, Frederick, MD 21702-1201, USA.
| | - Eric O Freed
- Virus-Cell Interaction Section, HIV Drug Resistance Program, National Cancer Institute at Frederick, Frederick, MD 21702-1201, USA.
| | - Michael F Summers
- Howard Hughes Medical Institute, University of Maryland Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250, USA.
| |
Collapse
|
36
|
Binnetoglu A, Sari M, Baglam T, Erbarut Seven I, Yumusakhuylu AC, Topuz MF, Batman C. Fascin expression in cholesteatoma: correlation with destruction of the ossicular chain and extent of disease. Clin Otolaryngol 2015; 40:335-40. [PMID: 25581788 DOI: 10.1111/coa.12373] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/06/2015] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Fascin is an actin-bundling protein found in cell membrane protrusions and increases cell motility. The expression of fascin in epithelial neoplasms has been described only recently. No data are available concerning the role of this protein in invasive cholesteatoma. Thus, we investigated the expression of fascin in cholesteatoma tissue and the relationship between fascin expression and intraoperative evaluation of the destruction of the ossicular chain and extent of disease. METHOD Cholesteatoma specimens of 28 patients and external auditory canal (EAC) skin specimens of the same patients (as the control group) were collected from mastoidectomies. Immunohistochemical technique was used to investigate the fascin expression in all cholesteatoma tissues and EAC skin specimens. Immunohistochemical staining was assessed semiquantitatively based on the thickness of epithelium. SPSS software version 16.0 (SPSS Inc., Chicago, IL, USA) was performed to statistically analyse the relationships between fascin expression and intraoperative evaluation destruction of ossicular chain and extent of the disease. RESULTS Immunohistochemically, there was no or very low fascin expression observed in normal epithelial cells of EAC skin, while expressed in cholesteatoma tissue. Also, fascin expression in cholesteatoma tissues was significantly correlated with destruction of ossicular chain and extent of the disease. CONCLUSIONS Fascin expression is usually found in cholesteatoma epithelium and is correlated with destruction of the ossicular chain and extent of disease. Considering all of the correlations between the clinical and histopathological findings, 'fascin immunoexpression scoring' may be used for histological grading of cholesteatoma.
Collapse
Affiliation(s)
- A Binnetoglu
- Department of Otorhinolaryngology-Head and Neck Surgery, Marmara University, Pendik Training and Research Hospital, Istanbul, Turkey
| | - M Sari
- Department of Otorhinolaryngology-Head and Neck Surgery, Marmara University, Pendik Training and Research Hospital, Istanbul, Turkey
| | - T Baglam
- Department of Otorhinolaryngology-Head and Neck Surgery, Marmara University, Pendik Training and Research Hospital, Istanbul, Turkey
| | - I Erbarut Seven
- Department of Pathology, Marmara University, Pendik Training and Research Hospital, Istanbul, Turkey
| | - A C Yumusakhuylu
- Department of Otorhinolaryngology-Head and Neck Surgery, Marmara University, Pendik Training and Research Hospital, Istanbul, Turkey
| | - M F Topuz
- Department of Otorhinolaryngology-Head and Neck Surgery, Marmara University, Pendik Training and Research Hospital, Istanbul, Turkey
| | - C Batman
- Department of Otorhinolaryngology-Head and Neck Surgery, Marmara University, Pendik Training and Research Hospital, Istanbul, Turkey
| |
Collapse
|
37
|
Wan C, Wu B, Song Z, Zhang J, Chu H, Wang A, Liu Q, Shi Y, Li G, Wang J. Insights into the molecular recognition of the granuphilin C2A domain with PI(4,5)P2. Chem Phys Lipids 2015; 186:61-7. [PMID: 25595293 DOI: 10.1016/j.chemphyslip.2015.01.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/11/2015] [Accepted: 01/12/2015] [Indexed: 01/06/2023]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) is a key player in regulating the process of excytosis, including insulin secretion. Granuphilin, a tandem C2 domain containing protein, mediates the docking of insulin granules onto plasma membrane. The C2A domain plays key roles in this process through interaction with PI(4,5)P2. In this study, we have investigated the molecular recognition mechanism of granuphilin-C2A domain to PI(4,5)P2 head group, and further to PI(4,5)P2-nanodisc by NMR, ITC, MST and SEC methods. Our results demonstrate that PI(4,5)P2 binds to the concave surface of granuphilin-C2A domain. The key residues involved in the binding were validated by mutation analysis.
Collapse
Affiliation(s)
- Chanjuan Wan
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, PR China
| | - Bo Wu
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, PR China.
| | - Zhenwei Song
- Heifei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, PR China
| | - Jiahai Zhang
- Heifei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, PR China
| | - Huiying Chu
- Laboratory of Molecular Modeling and Design, State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Rd., Dalian 116023, PR China
| | - Aoli Wang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, PR China
| | - Qingsong Liu
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, PR China
| | - Yunyu Shi
- Heifei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei 230027, PR China
| | - Guohui Li
- Laboratory of Molecular Modeling and Design, State key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Rd., Dalian 116023, PR China
| | - Junfeng Wang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, PR China.
| |
Collapse
|
38
|
Tyson GH, Halavaty AS, Kim H, Geissler B, Agard M, Satchell KJ, Cho W, Anderson WF, Hauser AR. A novel phosphatidylinositol 4,5-bisphosphate binding domain mediates plasma membrane localization of ExoU and other patatin-like phospholipases. J Biol Chem 2014; 290:2919-37. [PMID: 25505182 DOI: 10.1074/jbc.m114.611251] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Bacterial toxins require localization to specific intracellular compartments following injection into host cells. In this study, we examined the membrane targeting of a broad family of bacterial proteins, the patatin-like phospholipases. The best characterized member of this family is ExoU, an effector of the Pseudomonas aeruginosa type III secretion system. Upon injection into host cells, ExoU localizes to the plasma membrane, where it uses its phospholipase A2 activity to lyse infected cells. The targeting mechanism of ExoU is poorly characterized, but it was recently found to bind to the phospholipid phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2), a marker for the plasma membrane of eukaryotic cells. We confirmed that the membrane localization domain (MLD) of ExoU had a direct affinity for PI(4,5)P2, and we determined that this binding was required for ExoU localization. Previously uncharacterized ExoU homologs from Pseudomonas fluorescens and Photorhabdus asymbiotica also localized to the plasma membrane and required PI(4,5)P2 for this localization. A conserved arginine within the MLD was critical for interaction of each protein with PI(4,5)P2 and for localization. Furthermore, we determined the crystal structure of the full-length P. fluorescens ExoU and found that it was similar to that of P. aeruginosa ExoU. Each MLD contains a four-helical bundle, with the conserved arginine exposed at its cap to allow for interaction with the negatively charged PI(4,5)P2. Overall, these findings provide a structural explanation for the targeting of patatin-like phospholipases to the plasma membrane and define the MLD of ExoU as a member of a new class of PI(4,5)P2 binding domains.
Collapse
Affiliation(s)
| | - Andrei S Halavaty
- Biochemistry and Center for Structural Genomics of Infectious Diseases, Northwestern University, Chicago, Illinois 60611 and
| | - Hyunjin Kim
- the Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607
| | | | | | | | - Wonhwa Cho
- the Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607
| | - Wayne F Anderson
- Biochemistry and Center for Structural Genomics of Infectious Diseases, Northwestern University, Chicago, Illinois 60611 and
| | - Alan R Hauser
- From the Departments of Microbiology-Immunology, Medicine, and
| |
Collapse
|
39
|
Barroso-González J, García-Expósito L, Puigdomènech I, de Armas-Rillo L, Machado JD, Blanco J, Valenzuela-Fernández A. Viral infection. Commun Integr Biol 2014. [DOI: 10.4161/cib.16716] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
|
40
|
Abstract
Dynamin is a large GTPase that mediates plasma membrane fission during clathrin-mediated endocytosis. Dynamin assembles into polymers on the necks of budding membranes in cells and has been shown to undergo GTP-dependent conformational changes that lead to membrane fission in vitro. Recent efforts have shed new light on the mechanisms of dynamin-mediated fission, yet exactly how dynamin performs this function in vivo is still not fully understood. Dynamin interacts with a number of proteins during the endocytic process. These interactions are mediated by the C-terminal proline-rich domain (PRD) of dynamin binding to SH3 domain-containing proteins. Three of these dynamin-binding partners (intersectin, amphiphysin and endophilin) have been shown to play important roles in the clathrin-mediated endocytosis process. They promote dynamin-mediated plasma membrane fission by regulating three important sequential steps in the process: recruitment of dynamin to sites of endocytosis; assembly of dynamin into a functional fission complex at the necks of clathrin-coated pits (CCPs); and regulation of dynamin-stimulated GTPase activity, a key requirement for fission.
Collapse
|
41
|
Eckey K, Wrobel E, Strutz-Seebohm N, Pott L, Schmitt N, Seebohm G. Novel Kv7.1-phosphatidylinositol 4,5-bisphosphate interaction sites uncovered by charge neutralization scanning. J Biol Chem 2014; 289:22749-22758. [PMID: 24947509 DOI: 10.1074/jbc.m114.589796] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Kv7.1 to Kv7.5 α-subunits belong to the family of voltage-gated potassium channels (Kv). Assembled with the β-subunit KCNE1, Kv7.1 conducts the slowly activating potassium current IKs, which is one of the major currents underlying repolarization of the cardiac action potential. A known regulator of Kv7 channels is the lipid phosphatidylinositol 4,5-bisphosphate (PIP2). PIP2 increases the macroscopic current amplitude by stabilizing the open conformation of 7.1/KCNE1 channels. However, knowledge about the exact nature of the interaction is incomplete. The aim of this study was the identification of the amino acids responsible for the interaction between Kv7.1 and PIP2. We generated 13 charge neutralizing point mutations at the intracellular membrane border and characterized them electrophysiologically in complex with KCNE1 under the influence of diC8-PIP2. Electrophysiological analysis of corresponding long QT syndrome mutants suggested impaired PIP2 regulation as the cause for channel dysfunction. To clarify the underlying structural mechanism of PIP2 binding, molecular dynamics simulations of Kv7.1/KCNE1 complexes containing two PIP2 molecules in each subunit at specific sites were performed. Here, we identified a subset of nine residues participating in the interaction of PIP2 and Kv7.1/KCNE1. These residues may form at least two binding pockets per subunit, leading to the stabilization of channel conformations upon PIP2 binding.
Collapse
Affiliation(s)
- Karina Eckey
- Department of Biochemistry I-Cation Channel Group, Ruhr University Bochum, 44801 Bochum, Germany; International Graduate School of Neuroscience, Ruhr University Bochum, 44801 Bochum, Germany; Ruhr University Bochum Research School, and Ruhr University Bochum, 44801 Bochum, Germany
| | - Eva Wrobel
- IfGH-Myocellular Electrophysiology, Department of Cardiovascular Medicine, University Hospital of Münster, 48149 Münster, Germany, and
| | - Nathalie Strutz-Seebohm
- IfGH-Myocellular Electrophysiology, Department of Cardiovascular Medicine, University Hospital of Münster, 48149 Münster, Germany, and
| | - Lutz Pott
- Institute of Physiology, Ruhr University Bochum, 44801 Bochum, Germany
| | - Nicole Schmitt
- Danish National Research Foundation Centre for Cardiac Arrhythmia, University of Copenhagen, 1165 Copenhagen, Denmark
| | - Guiscard Seebohm
- International Graduate School of Neuroscience, Ruhr University Bochum, 44801 Bochum, Germany; Ruhr University Bochum Research School, and Ruhr University Bochum, 44801 Bochum, Germany; IfGH-Myocellular Electrophysiology, Department of Cardiovascular Medicine, University Hospital of Münster, 48149 Münster, Germany, and.
| |
Collapse
|
42
|
Dutta Roy R, Stefan MI, Rosenmund C. Biophysical properties of presynaptic short-term plasticity in hippocampal neurons: insights from electrophysiology, imaging and mechanistic models. Front Cell Neurosci 2014; 8:141. [PMID: 24904286 PMCID: PMC4033079 DOI: 10.3389/fncel.2014.00141] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Accepted: 05/01/2014] [Indexed: 11/16/2022] Open
Abstract
Hippocampal neurons show different types of short-term plasticity (STP). Some exhibit facilitation of their synaptic responses and others depression. In this review we discuss presynaptic biophysical properties behind heterogeneity in STP in hippocampal neurons such as alterations in vesicle priming and docking, fusion, neurotransmitter filling and vesicle replenishment. We look into what types of information electrophysiology, imaging and mechanistic models have given about the time scales and relative impact of the different properties on STP with an emphasis on the use of mechanistic models as complementary tools to experimental procedures. Taken together this tells us that it is possible for a multitude of different mechanisms to underlie the same STP pattern, even though some are more important in specific cases, and that mechanistic models can be used to integrate the biophysical properties to see which mechanisms are more important in specific cases of STP.
Collapse
Affiliation(s)
- Ranjita Dutta Roy
- Department of Medicine Solna, Karolinska Insitutet Stockholm, Sweden ; Neuroscience Research Center (NWFZ), Charite Universitatsmedizin Berlin, Germany
| | - Melanie I Stefan
- Department of Neurobiology, Harvard Medical School Boston, MA, USA
| | - Christian Rosenmund
- Neuroscience Research Center (NWFZ), Charite Universitatsmedizin Berlin, Germany
| |
Collapse
|
43
|
PIPKIIα is widely expressed in hematopoietic-derived cells and may play a role in the expression of alpha- and gamma-globins in K562 cells. Mol Cell Biochem 2014; 393:145-53. [DOI: 10.1007/s11010-014-2054-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 04/03/2014] [Indexed: 10/25/2022]
|
44
|
Trésaugues L, Silvander C, Flodin S, Welin M, Nyman T, Gräslund S, Hammarström M, Berglund H, Nordlund P. Structural basis for phosphoinositide substrate recognition, catalysis, and membrane interactions in human inositol polyphosphate 5-phosphatases. Structure 2014; 22:744-55. [PMID: 24704254 DOI: 10.1016/j.str.2014.01.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Revised: 01/24/2014] [Accepted: 01/24/2014] [Indexed: 11/15/2022]
Abstract
SHIP2, OCRL, and INPP5B belong to inositol polyphosphate 5-phophatase subfamilies involved in insulin regulation and Lowes syndrome. The structural basis for membrane recognition, substrate specificity, and regulation of inositol polyphosphate 5-phophatases is still poorly understood. We determined the crystal structures of human SHIP2, OCRL, and INPP5B, the latter in complex with phosphoinositide substrate analogs, which revealed a membrane interaction patch likely to assist in sequestering substrates from the lipid bilayer. Residues recognizing the 1-phosphate of the substrates are highly conserved among human family members, suggesting similar substrate binding modes. However, 3- and 4-phosphate recognition varies and determines individual substrate specificity profiles. The high conservation of the environment of the scissile 5-phosphate suggests a common reaction geometry for all members of the human 5-phosphatase family.
Collapse
Affiliation(s)
- Lionel Trésaugues
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Camilla Silvander
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden.
| | - Susanne Flodin
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Martin Welin
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Tomas Nyman
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Susanne Gräslund
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Martin Hammarström
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Helena Berglund
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden
| | - Pär Nordlund
- Structural Genomics Consortium, Karolinska Institutet, 17177 Stockholm, Sweden; Division of Biophysics, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, 17177 Stockholm, Sweden; Centre for Biomedical Structural Biology, School of Biological Sciences, Nanyang Technological University, 637551, Singapore.
| |
Collapse
|
45
|
Schill NJ, Hedman AC, Choi S, Anderson RA. Isoform 5 of PIPKIγ regulates the endosomal trafficking and degradation of E-cadherin. J Cell Sci 2014; 127:2189-203. [PMID: 24610942 DOI: 10.1242/jcs.132423] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Phosphatidylinositol phosphate kinases (PIPKs) have distinct cellular targeting, allowing for site-specific synthesis of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] to activate specific signaling cascades required for cellular processes. Several C-terminal splice variants of PIPKIγ (also known as PIP5K1C) exist, and have been implicated in a multitude of cellular roles. PI(4,5)P2 serves as a fundamental regulator of E-cadherin transport, and PI(4,5)P2-generating enzymes are important signaling relays in these pathways. We present evidence that the isoform 5 splice variant of PIPKIγ (PIPKIγi5) associates with E-cadherin and promotes its lysosomal degradation. Additionally, we show that the endosomal trafficking proteins SNX5 and SNX6 associate with PIPKIγi5 and inhibit PIPKIγi5-mediated E-cadherin degradation. Following HGF stimulation, activated Src directly phosphorylates PIPKIγi5. Phosphorylation of the PIPKIγi5 C-terminus regulates its association with SNX5 and, consequently, E-cadherin degradation. Additionally, this PIPKIγi5-mediated pathway requires Rab7 to promote degradation of internalized E-cadherin. Taken together, the data indicate that PIPKIγi5 and SNX5 are crucial regulators of E-cadherin sorting and degradation. PIPKIγi5, SNX and phosphoinositide regulation of lysosomal sorting represent a novel area of PI(4,5)P2 signaling and research. PIPKIγi5 regulation of E-cadherin sorting for degradation might have broad implications in development and tissue maintenance, and enhanced PIPKIγi5 function might have pathogenic consequences due to downregulation of E-cadherin.
Collapse
Affiliation(s)
- Nicholas J Schill
- Department of Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Andrew C Hedman
- Department of Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Suyong Choi
- Program in Cellular & Molecular Biology, Laboratory of Molecular Biology, University of Wisconsin-Madison, 1525 Linden Drive, Madison, WI 53706, USA
| | - Richard A Anderson
- Department of Pharmacology, University of Wisconsin-Madison School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| |
Collapse
|
46
|
Liang T, Xie L, Chao C, Kang Y, Lin X, Qin T, Xie H, Feng ZP, Gaisano HY. Phosphatidylinositol 4,5-biphosphate (PIP2) modulates interaction of syntaxin-1A with sulfonylurea receptor 1 to regulate pancreatic β-cell ATP-sensitive potassium channels. J Biol Chem 2014; 289:6028-40. [PMID: 24429282 DOI: 10.1074/jbc.m113.511808] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
In β-cells, syntaxin (Syn)-1A interacts with SUR1 to inhibit ATP-sensitive potassium channels (KATP channels). PIP2 binds the Kir6.2 subunit to open KATP channels. PIP2 also modifies Syn-1A clustering in plasma membrane (PM) that may alter Syn-1A actions on PM proteins like SUR1. Here, we assessed whether the actions of PIP2 on activating KATP channels is contributed by sequestering Syn-1A from binding SUR1. In vitro binding showed that PIP2 dose-dependently disrupted Syn-1A·SUR1 complexes, corroborated by an in vivo Forster resonance energy transfer assay showing disruption of SUR1(-EGFP)/Syn-1A(-mCherry) interaction along with increased Syn-1A cluster formation. Electrophysiological studies of rat β-cells, INS-1, and SUR1/Kir6.2-expressing HEK293 cells showed that PIP2 dose-dependent activation of KATP currents was uniformly reduced by Syn-1A. To unequivocally distinguish between PIP2 actions on Syn-1A and Kir6.2, we employed several strategies. First, we showed that PIP2-insensitive Syn-1A-5RK/A mutant complex with SUR1 could not be disrupted by PIP2, consequently reducing PIP2 activation of KATP channels. Next, Syn-1A·SUR1 complex modulation of KATP channels could be observed at a physiologically low PIP2 concentration that did not disrupt the Syn-1A·SUR1 complex, compared with higher PIP2 concentrations acting directly on Kir6.2. These effects were specific to PIP2 and not observed with physiologic concentrations of other phospholipids. Finally, depleting endogenous PIP2 with polyphosphoinositide phosphatase synaptojanin-1, known to disperse Syn-1A clusters, freed Syn-1A from Syn-1A clusters to bind SUR1, causing inhibition of KATP channels that could no longer be further inhibited by exogenous Syn-1A. These results taken together indicate that PIP2 affects islet β-cell KATP channels not only by its actions on Kir6.2 but also by sequestering Syn-1A to modulate Syn-1A availability and its interactions with SUR1 on PM.
Collapse
Affiliation(s)
- Tao Liang
- From the Departments of Medicine and
| | | | | | | | | | | | | | | | | |
Collapse
|
47
|
The molecular biology of Bluetongue virus replication. Virus Res 2013; 182:5-20. [PMID: 24370866 DOI: 10.1016/j.virusres.2013.12.017] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/10/2013] [Accepted: 12/11/2013] [Indexed: 01/17/2023]
Abstract
The members of Orbivirus genus within the Reoviridae family are arthropod-borne viruses which are responsible for high morbidity and mortality in ruminants. Bluetongue virus (BTV) which causes disease in livestock (sheep, goat, cattle) has been in the forefront of molecular studies for the last three decades and now represents the best understood orbivirus at a molecular and structural level. The complex nature of the virion structure has been well characterised at high resolution along with the definition of the virus encoded enzymes required for RNA replication; the ordered assembly of the capsid shell as well as the protein and genome sequestration required for it; and the role of host proteins in virus entry and virus release. More recent developments of Reverse Genetics and Cell-Free Assembly systems have allowed integration of the accumulated structural and molecular knowledge to be tested at meticulous level, yielding higher insight into basic molecular virology, from which the rational design of safe efficacious vaccines has been possible. This article is centred on the molecular dissection of BTV with a view to understanding the role of each protein in the virus replication cycle. These areas are important in themselves for BTV replication but they also indicate the pathways that related viruses, which includes viruses that are pathogenic to man and animals, might also use providing an informed starting point for intervention or prevention.
Collapse
|
48
|
Kabachinski G, Yamaga M, Kielar-Grevstad DM, Bruinsma S, Martin TFJ. CAPS and Munc13 utilize distinct PIP2-linked mechanisms to promote vesicle exocytosis. Mol Biol Cell 2013; 25:508-21. [PMID: 24356451 PMCID: PMC3923642 DOI: 10.1091/mbc.e12-11-0829] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Phosphoinositides provide compartment-specific signals for membrane trafficking. Plasma membrane phosphatidylinositol 4,5-bisphosphate (PIP2) is required for Ca(2+)-triggered vesicle exocytosis, but whether vesicles fuse into PIP2-rich membrane domains in live cells and whether PIP2 is metabolized during Ca(2+)-triggered fusion were unknown. Ca(2+)-dependent activator protein in secretion 1 (CAPS-1; CADPS/UNC31) and ubMunc13-2 (UNC13B) are PIP2-binding proteins required for Ca(2+)-triggered vesicle exocytosis in neuroendocrine PC12 cells. These proteins are likely effectors for PIP2, but their localization during exocytosis had not been determined. Using total internal reflection fluorescence microscopy in live cells, we identify PIP2-rich membrane domains at sites of vesicle fusion. CAPS is found to reside on vesicles but depends on plasma membrane PIP2 for its activity. Munc13 is cytoplasmic, but Ca(2+)-dependent translocation to PIP2-rich plasma membrane domains is required for its activity. The results reveal that vesicle fusion into PIP2-rich membrane domains is facilitated by sequential PIP2-dependent activation of CAPS and PIP2-dependent recruitment of Munc13. PIP2 hydrolysis only occurs under strong Ca(2+) influx conditions sufficient to activate phospholipase Cη2 (PLCη2). Such conditions reduce CAPS activity and enhance Munc13 activity, establishing PLCη2 as a Ca(2+)-dependent modulator of exocytosis. These studies provide a direct view of the spatial distribution of PIP2 linked to vesicle exocytosis via regulation of lipid-dependent protein effectors CAPS and Munc13.
Collapse
Affiliation(s)
- Greg Kabachinski
- Department of Biochemistry, University of Wisconsin, Madison, WI 53706
| | | | | | | | | |
Collapse
|
49
|
Sarmento MJ, Coutinho A, Fedorov A, Prieto M, Fernandes F. Ca(2+) induces PI(4,5)P2 clusters on lipid bilayers at physiological PI(4,5)P2 and Ca(2+) concentrations. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1838:822-30. [PMID: 24316170 DOI: 10.1016/j.bbamem.2013.11.020] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 11/22/2013] [Accepted: 11/26/2013] [Indexed: 01/22/2023]
Abstract
Calcium has been shown to induce clustering of PI(4,5)P2 at high and non-physiological concentrations of both the divalent ion and the phosphatidylinositol, or on supported lipid monolayers. In lipid bilayers at physiological conditions, clusters are not detected through microscopic techniques. Here, we aimed to determine through spectroscopic methodologies if calcium plays a role in PI(4,5)P2 lateral distribution on lipid bilayers under physiological conditions. Using several different approaches which included information on fluorescence quantum yield, polarization, spectra and diffusion properties of a fluorescent derivative of PI(4,5)P2 (TopFluor(TF)-PI(4,5)P2), we show that Ca(2+) promotes PI(4,5)P2 clustering in lipid bilayers at physiological concentrations of both Ca(2+) and PI(4,5)P2. Fluorescence depolarization data of TF-PI(4,5)P2 in the presence of calcium suggests that under physiological concentrations of PI(4,5)P2 and calcium, the average cluster size comprises ~15 PI(4,5)P2 molecules. The presence of Ca(2+)-induced PI(4,5)P2 clusters is supported by FCS data. Additionally, calcium mediated PI(4,5)P2 clustering was more pronounced in liquid ordered (lo) membranes, and the PI(4,5)P2-Ca(2+) clusters presented an increased affinity for lo domains. In this way, PI(4,5)P2 could function as a lipid calcium sensor and the increased efficiency of calcium-mediated PI(4,5)P2 clustering on lo domains might provide targeted nucleation sites for PI(4,5)P2 clusters upon calcium stimulus.
Collapse
Affiliation(s)
- Maria J Sarmento
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Ana Coutinho
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal; Departamento de Química e Bioquímica, FCUL, University of Lisbon, Lisbon, Portugal
| | - Aleksander Fedorov
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Manuel Prieto
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal
| | - Fabio Fernandes
- Centro de Química-Física Molecular and Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, University of Lisbon, Lisbon, Portugal.
| |
Collapse
|
50
|
James DJ, Martin TFJ. CAPS and Munc13: CATCHRs that SNARE Vesicles. Front Endocrinol (Lausanne) 2013; 4:187. [PMID: 24363652 PMCID: PMC3849599 DOI: 10.3389/fendo.2013.00187] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 11/18/2013] [Indexed: 11/13/2022] Open
Abstract
CAPS (Calcium-dependent Activator Protein for Secretion, aka CADPS) and Munc13 (Mammalian Unc-13) proteins function to prime vesicles for Ca(2+)-triggered exocytosis in neurons and neuroendocrine cells. CAPS and Munc13 proteins contain conserved C-terminal domains that promote the assembly of SNARE complexes for vesicle priming. Similarities of the C-terminal domains of CAPS/Munc13 proteins with Complex Associated with Tethering Containing Helical Rods domains in multi-subunit tethering complexes (MTCs) have been reported. MTCs coordinate multiple interactions for SNARE complex assembly at constitutive membrane fusion steps. We review aspects of these diverse tethering and priming factors to identify common operating principles.
Collapse
Affiliation(s)
- Declan J. James
- Department of Biochemistry, University of Wisconsin, Madison, WI, USA
| | - Thomas F. J. Martin
- Department of Biochemistry, University of Wisconsin, Madison, WI, USA
- *Correspondence: Thomas F. J. Martin, Department of Biochemistry, University of Wisconsin, 433 Babcock Drive, Madison, WI 53706, USA e-mail:
| |
Collapse
|