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Yu F, Machaca K. Remodeling of ER Membrane Contact Sites During Cell Division. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2025; 8:25152564241309207. [PMID: 39881950 PMCID: PMC11775993 DOI: 10.1177/25152564241309207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2024] [Revised: 12/03/2024] [Accepted: 12/04/2024] [Indexed: 01/31/2025]
Abstract
Membrane contact sites (MCS) provide specialized conduits for inter-organelle communications to maintain cellular homeostasis. Most organelles are interconnected, which supports their coordination and function. M-phase (mitosis or meiosis) is associated with dramatic cellular remodeling to support cell division, including the equal distribution of organelles to the two daughter cells. However, the fate of MCS in M-phase is poorly understood. Here we review recent advances arguing for differential remodeling of endoplasmic reticulum (ER) MCS with the plasma membrane (PM, ERPMCS) and the mitochondria (MERCS) during cell division.
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Affiliation(s)
- Fang Yu
- Calcium Signaling Group, Research Department, Weill Cornell Medicine Qatar, Doha, Qatar
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Khaled Machaca
- Calcium Signaling Group, Research Department, Weill Cornell Medicine Qatar, Doha, Qatar
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
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2
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Gamuyao R, Chang CL. Imaging and proteomics toolkits for studying organelle contact sites. Front Cell Dev Biol 2024; 12:1466915. [PMID: 39381373 PMCID: PMC11458464 DOI: 10.3389/fcell.2024.1466915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2024] [Accepted: 09/05/2024] [Indexed: 10/10/2024] Open
Abstract
Organelle contact sites are regions where two heterologous membranes are juxtaposed by molecular tethering complexes. These contact sites are important in inter-organelle communication and cellular functional integration. However, visualizing these minute foci and identifying contact site proteomes have been challenging. In recent years, fluorescence-based methods have been developed to visualize the dynamic physical interaction of organelles while proximity labeling approaches facilitate the profiling of proteomes at contact sites. In this review, we explain the design principle for these contact site reporters: a dual-organelle interaction mechanism based on how endogenous tethers and/or tethering complexes localize to contact sites. We classify the contact site reporters into three categories: (i) single-protein systems, (ii) two-component systems with activated reporter signal upon organelle proximity, and (iii) reporters for contact site proteomes. We also highlight advanced imaging analysis with high temporal-spatial resolution and the use of machine-learning algorithms for detecting contact sites.
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Affiliation(s)
| | - Chi-Lun Chang
- Department of Cell and Molecular Biology, St. Jude Children’s Research Hospital, Memphis, TN, United States
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3
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Elgendy M, Tamada H, Taira T, Iio Y, Kawamura A, Kunogi A, Mizutani Y, Kiyama H. Dynamic changes in endoplasmic reticulum morphology and its contact with the plasma membrane in motor neurons in response to nerve injury. Cell Tissue Res 2024; 396:71-84. [PMID: 38311679 PMCID: PMC10997708 DOI: 10.1007/s00441-024-03858-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 12/29/2023] [Indexed: 02/06/2024]
Abstract
The endoplasmic reticulum (ER) extends throughout a cell and plays a critical role in maintaining cellular homeostasis. Changes in ER shape could provide a clue to explore the mechanisms that underlie the fate determination of neurons after axon injury because the ER drastically changes its morphology under neuronal stress to maintain cellular homeostasis and recover from damage. Because of their tiny structures and richness in the soma, the detailed morphology of the ER and its dynamics have not been well analysed. In this study, the focused ion beam/scanning electron microscopy (FIB/SEM) analysis was performed to explore the ultra-structures of the ER in the somata of motor neuron with axon regenerative injury models. In normal motor neurons, ER in the somata is abundantly localised near the perinucleus and represents lamella-like structures. After injury, analysis of the ER volume and ER branching points indicated a collapse of the normal distribution and a transformation from lamella-like structures to mesh-like structures. Furthermore, accompanied by ER accumulation near the plasma membrane (PM), the contact between the ER and PM (ER-PM contacts) significantly increased after injury. The accumulation of extended-synaptotagmin 1 (E-Syt1), a tethering protein of the ER and PM that regulates Ca2+-dependent lipid transfer, was also identified by immunohistochemistry and quantitative Real-time PCR after injury. These morphological alterations of ER and the increase in ER-PM contacts may be crucial events that occur in motor neurons as a resilient response for the survival after axonal injury.
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Affiliation(s)
- Mahmoud Elgendy
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Damanhour University, Damanhour, 22511, Egypt
| | - Hiromi Tamada
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan.
- Anatomy, Graduate School of Medicines, University of Fukui, Matsuokashimoaizuki, Eiheiji-Cho, Yoshida-gun, Fukui, 910-1193, Japan.
| | - Takaya Taira
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Yuma Iio
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Akinobu Kawamura
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Ayusa Kunogi
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Yuka Mizutani
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan
| | - Hiroshi Kiyama
- Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa-Ku, Nagoya, Aichi, 466-8550, Japan.
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4
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Sarhadi TR, Panse JS, Nagotu S. Mind the gap: Methods to study membrane contact sites. Exp Cell Res 2023; 431:113756. [PMID: 37633408 DOI: 10.1016/j.yexcr.2023.113756] [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: 03/28/2023] [Revised: 08/11/2023] [Accepted: 08/13/2023] [Indexed: 08/28/2023]
Abstract
Organelles are dynamic entities whose functions are essential for the optimum functioning of cells. It is now known that the juxtaposition of organellar membranes is essential for the exchange of metabolites and their communication. These functional apposition sites are termed membrane contact sites. Dynamic membrane contact sites between various sub-cellular structures such as mitochondria, endoplasmic reticulum, peroxisomes, Golgi apparatus, lysosomes, lipid droplets, plasma membrane, endosomes, etc. have been reported in various model systems. The burgeoning area of research on membrane contact sites has witnessed several manuscripts in recent years that identified the contact sites and components involved. Several methods have been developed to identify, measure and analyze the membrane contact sites. In this manuscript, we aim to discuss important methods developed to date that are used to study membrane contact sites.
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Affiliation(s)
- Tanveera Rounaque Sarhadi
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| | - Janhavee Shirish Panse
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India
| | - Shirisha Nagotu
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
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5
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Zhao G, Liu S, Arun S, Renda F, Khodjakov A, Pellman D. A tubule-sheet continuum model for the mechanism of nuclear envelope assembly. Dev Cell 2023; 58:847-865.e10. [PMID: 37098350 PMCID: PMC10205699 DOI: 10.1016/j.devcel.2023.04.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/25/2023] [Accepted: 04/01/2023] [Indexed: 04/27/2023]
Abstract
Nuclear envelope (NE) assembly defects cause chromosome fragmentation, cancer, and aging. However, major questions about the mechanism of NE assembly and its relationship to nuclear pathology are unresolved. In particular, how cells efficiently assemble the NE starting from vastly different, cell type-specific endoplasmic reticulum (ER) morphologies is unclear. Here, we identify a NE assembly mechanism, "membrane infiltration," that defines one end of a continuum with another NE assembly mechanism, "lateral sheet expansion," in human cells. Membrane infiltration involves the recruitment of ER tubules or small sheets to the chromatin surface by mitotic actin filaments. Lateral sheet expansion involves actin-independent envelopment of peripheral chromatin by large ER sheets that then extend over chromatin within the spindle. We propose a "tubule-sheet continuum" model that explains the efficient NE assembly from any starting ER morphology, the cell type-specific patterns of nuclear pore complex (NPC) assembly, and the obligatory NPC assembly defect of micronuclei.
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Affiliation(s)
- Gengjing Zhao
- Howard Hughes Medical Institute, Chevy Chase, MD, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA; Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Shiwei Liu
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Sanjana Arun
- Howard Hughes Medical Institute, Chevy Chase, MD, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA; Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Fioranna Renda
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - Alexey Khodjakov
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | - David Pellman
- Howard Hughes Medical Institute, Chevy Chase, MD, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA, USA; Department of Cell Biology, Harvard Medical School, Boston, MA, USA.
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6
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Ivanova A, Atakpa-Adaji P. Phosphatidylinositol 4,5-bisphosphate and calcium at ER-PM junctions - Complex interplay of simple messengers. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119475. [PMID: 37098393 DOI: 10.1016/j.bbamcr.2023.119475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 03/05/2023] [Accepted: 04/03/2023] [Indexed: 04/27/2023]
Abstract
Endoplasmic reticulum-plasma membrane contact sites (ER-PM MCS) are a specialised domain involved in the control of Ca2+ dynamics and various Ca2+-dependent cellular processes. Intracellular Ca2+ signals are broadly supported by Ca2+ release from intracellular Ca2+ channels such as inositol 1,4,5-trisphosphate receptors (IP3Rs) and subsequent store-operated Ca2+ entry (SOCE) across the PM to replenish store content. IP3Rs sit in close proximity to the PM where they can easily access newly synthesised IP3, interact with binding partners such as actin, and localise adjacent to ER-PM MCS populated by the SOCE machinery, STIM1-2 and Orai1-3, to possibly form a locally regulated unit of Ca2+ influx. PtdIns(4,5)P2 is a multiplex regulator of Ca2+ signalling at the ER-PM MCS interacting with multiple proteins at these junctions such as actin and STIM1, whilst also being consumed as a substrate for phospholipase C to produce IP3 in response to extracellular stimuli. In this review, we consider the mechanisms regulating the synthesis and turnover of PtdIns(4,5)P2 via the phosphoinositide cycle and its significance for sustained signalling at the ER-PM MCS. Furthermore, we highlight recent insights into the role of PtdIns(4,5)P2 in the spatiotemporal organization of signalling at ER-PM junctions and raise outstanding questions on how this multi-faceted regulation occurs.
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Affiliation(s)
- Adelina Ivanova
- Department of Pharmacology, Tennis Court Road, Cambridge CB2 1PD, UK.
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7
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Lu W, Helou YA, Shrinivas K, Liou J, Au-Yeung BB, Weiss A. The phosphatidylinositol-transfer protein Nir3 promotes PI(4,5)P 2 replenishment in response to TCR signaling during T cell development and survival. Nat Immunol 2023; 24:136-147. [PMID: 36581712 PMCID: PMC9810531 DOI: 10.1038/s41590-022-01372-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 10/26/2022] [Indexed: 12/31/2022]
Abstract
Hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) by phospholipase C-γ (PLCγ1) represents a critical step in T cell antigen receptor (TCR) signaling and subsequent thymocyte and T cell responses. PIP2 replenishment following its depletion in the plasma membrane (PM) is dependent on delivery of its precursor phosphatidylinositol (PI) from the endoplasmic reticulum (ER) to the PM. We show that a PI transfer protein (PITP), Nir3 (Pitpnm2), promotes PIP2 replenishment following TCR stimulation and is important for T cell development. In Nir3-/- T lineage cells, the PIP2 replenishment following TCR stimulation is slower. Nir3 deficiency attenuates calcium mobilization in double-positive (DP) thymocytes in response to weak TCR stimulation. This impaired TCR signaling leads to attenuated thymocyte development at TCRβ selection and positive selection as well as diminished mature T cell fitness in Nir3-/- mice. This study highlights the importance of PIP2 replenishment mediated by PITPs at ER-PM junctions during TCR signaling.
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Affiliation(s)
- Wen Lu
- Rosalind Russell and Ephraim P. Engleman Rheumatology Research Center, Departments of Medicine and of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA
| | - Ynes A Helou
- Rosalind Russell and Ephraim P. Engleman Rheumatology Research Center, Departments of Medicine and of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA.,Clade Therapeutics, Cambridge, MA, USA
| | - Krishna Shrinivas
- NSF-Simons Center for Mathematical & Statistical Analysis of Biology, Harvard University, Cambridge, MA, USA
| | - Jen Liou
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Byron B Au-Yeung
- Division of Immunology, Lowance Center for Human Immunology, Department of Medicine, Emory University, Atlanta, GA, USA
| | - Arthur Weiss
- Rosalind Russell and Ephraim P. Engleman Rheumatology Research Center, Departments of Medicine and of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA, USA.
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8
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Nieto-Garai JA, Olazar-Intxausti J, Anso I, Lorizate M, Terrones O, Contreras FX. Super-Resolution Microscopy to Study Interorganelle Contact Sites. Int J Mol Sci 2022; 23:15354. [PMID: 36499680 PMCID: PMC9739495 DOI: 10.3390/ijms232315354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/29/2022] [Accepted: 12/03/2022] [Indexed: 12/12/2022] Open
Abstract
Interorganelle membrane contact sites (MCS) are areas of close vicinity between the membranes of two organelles that are maintained by protein tethers. Recently, a significant research effort has been made to study MCS, as they are implicated in a wide range of biological functions, such as organelle biogenesis and division, apoptosis, autophagy, and ion and phospholipid homeostasis. Their composition, characteristics, and dynamics can be studied by different techniques, but in recent years super-resolution fluorescence microscopy (SRFM) has emerged as a powerful tool for studying MCS. In this review, we first explore the main characteristics and biological functions of MCS and summarize the different approaches for studying them. Then, we center on SRFM techniques that have been used to study MCS. For each of the approaches, we summarize their working principle, discuss their advantages and limitations, and explore the main discoveries they have uncovered in the field of MCS.
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Affiliation(s)
- Jon Ander Nieto-Garai
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - June Olazar-Intxausti
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - Itxaso Anso
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
- Structural Glycobiology Laboratory, Biocruces Bizkaia Health Research Institute, Cruces University Hospital, 48903 Barakaldo, Spain
| | - Maier Lorizate
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - Oihana Terrones
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
| | - Francesc-Xabier Contreras
- Department of Biochemistry and Molecular Biology, Faculty of Science and Technology, University of the Basque Country (UPV/EHU), Barrio Sarriena s/n, 48940 Leioa, Spain
- Instituto Biofisika (UPV/EHU, CSIC), Barrio Sarriena s/n, 48940 Leioa, Spain
- Ikerbasque, Basque Foundation of Science, 48011 Bilbao, Spain
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9
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Zhou J, Corvaisier M, Malycheva D, Alvarado-Kristensson M. Hubbing the Cancer Cell. Cancers (Basel) 2022; 14:5924. [PMID: 36497405 PMCID: PMC9738523 DOI: 10.3390/cancers14235924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/24/2022] [Accepted: 11/28/2022] [Indexed: 12/02/2022] Open
Abstract
Oncogenic transformation drives adaptive changes in a growing tumor that affect the cellular organization of cancerous cells, resulting in the loss of specialized cellular functions in the polarized compartmentalization of cells. The resulting altered metabolic and morphological patterns are used clinically as diagnostic markers. This review recapitulates the known functions of actin, microtubules and the γ-tubulin meshwork in orchestrating cell metabolism and functional cellular asymmetry.
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Affiliation(s)
| | | | | | - Maria Alvarado-Kristensson
- Molecular Pathology, Department of Translational Medicine, Skåne University Hospital Malmö 1, Lund University, 20502 Malmö, Sweden
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10
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Chung GHC, Lorvellec M, Gissen P, Pichaud F, Burden JJ, Stefan CJ. The ultrastructural organization of endoplasmic reticulum-plasma membrane contacts is conserved in epithelial cells. Mol Biol Cell 2022; 33:ar113. [PMID: 35947498 PMCID: PMC9635291 DOI: 10.1091/mbc.e21-11-0534-t] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 07/26/2022] [Accepted: 08/02/2022] [Indexed: 11/11/2022] Open
Abstract
Contacts between the endoplasmic reticulum and the plasma membrane (ER-PM contacts) have important roles in membrane lipid and calcium dynamics, yet their organization in polarized epithelial cells has not been thoroughly described. Here we examine ER-PM contacts in hepatocytes in mouse liver using electron microscopy, providing the first comprehensive ultrastructural study of ER-PM contacts in a mammalian epithelial tissue. Our quantitative analyses reveal strikingly distinct ER-PM contact architectures spatially linked to apical, lateral, and basal PM domains. Notably, we find that an extensive network of ER-PM contacts exists at lateral PM domains that form intercellular junctions between hepatocytes. Moreover, the spatial organization of ER-PM contacts is conserved in epithelial spheroids, suggesting that ER-PM contacts may serve conserved roles in epithelial cell architecture. Consistent with this notion, we show that ORP5 activity at ER-PM contacts modulates the apical-basolateral aspect ratio in HepG2 cells. Thus ER-PM contacts have a conserved distribution and crucial roles in PM domain architecture across epithelial cell types.
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Affiliation(s)
- Gary Hong Chun Chung
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Maëlle Lorvellec
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
- NIHR Great Ormond Street Hospital Biomedical Research Centre, University College London, London WC1N 1EH, UK
| | - Paul Gissen
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
- NIHR Great Ormond Street Hospital Biomedical Research Centre, University College London, London WC1N 1EH, UK
| | - Franck Pichaud
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Jemima J. Burden
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
| | - Christopher J. Stefan
- Laboratory for Molecular Cell Biology, University College London, London WC1E 6BT, UK
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11
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STIM Proteins and Regulation of SOCE in ER-PM Junctions. Biomolecules 2022; 12:biom12081152. [PMID: 36009047 PMCID: PMC9405863 DOI: 10.3390/biom12081152] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/12/2022] [Accepted: 08/15/2022] [Indexed: 11/30/2022] Open
Abstract
ER-PM junctions are membrane contact sites formed by the endoplasmic reticulum (ER) and plasma membrane (PM) in close apposition together. The formation and stability of these junctions are dependent on constitutive and dynamic enrichment of proteins, which either contribute to junctional stability or modulate the lipid levels of both ER and plasma membranes. The ER-PM junctions have come under much scrutiny recently as they serve as hubs for assembling the Ca2+ signaling complexes. This review summarizes: (1) key findings that underlie the abilities of STIM proteins to accumulate in ER-PM junctions; (2) the modulation of Orai/STIM complexes by other components found within the same junction; and (3) how Orai1 channel activation is coordinated and coupled with downstream signaling pathways.
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12
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O'Callaghan P, Engberg A, Eriksson O, Fatsis-Kavalopoulos N, Stelzl C, Sanchez G, Idevall-Hagren O, Kreuger J. Piezo1 activation attenuates thrombin-induced blebbing in breast cancer cells. J Cell Sci 2022; 135:274949. [PMID: 35274124 PMCID: PMC9016622 DOI: 10.1242/jcs.258809] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 02/22/2022] [Indexed: 11/30/2022] Open
Abstract
Cancer cells exploit a variety of migration modes to leave primary tumors and establish metastases, including amoeboid cell migration, which is typically reliant on bleb formation. Here we demonstrate that thrombin induces dynamic blebbing in the MDA-MB-231 breast cancer cell line and confirm that protease-activated receptor 1 (PAR1) activation is sufficient to induce this effect. Cell confinement has been implicated as a driving force in bleb-based migration. Unexpectedly, we found that gentle contact compression, exerted using a custom built ‘cell press’ to mechanically stimulate cells, reduced thrombin-induced blebbing. Thrombin-induced blebbing was similarly attenuated using the small molecule Yoda1, an agonist of the mechanosensitive Ca2+ channel Piezo1, and this attenuation was impaired in Piezo1-depleted cells. Additionally, Piezo1 activation suppressed thrombin-induced phosphorylation of ezrin, radixin and moesin (ERM) proteins, which are implicated in the blebbing process. Our results provide mechanistic insights into Piezo1 activation as a suppressor of dynamic blebbing, specifically that which is induced by thrombin. Summary: Thrombin and protease-activated receptor agonists induce dynamic blebbing in breast cancer cells, which can be attenuated by contact-mediated compression, and activation of the mechanosensitive ion channel Piezo1.
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Affiliation(s)
- Paul O'Callaghan
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Adam Engberg
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Olle Eriksson
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | | | - Christina Stelzl
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Gonzalo Sanchez
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | | | - Johan Kreuger
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
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13
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Maltan L, Andova AM, Derler I. The Role of Lipids in CRAC Channel Function. Biomolecules 2022; 12:biom12030352. [PMID: 35327543 PMCID: PMC8944985 DOI: 10.3390/biom12030352] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/12/2022] [Accepted: 02/20/2022] [Indexed: 11/28/2022] Open
Abstract
The composition and dynamics of the lipid membrane define the physical properties of the bilayer and consequently affect the function of the incorporated membrane transporters, which also applies for the prominent Ca2+ release-activated Ca2+ ion channel (CRAC). This channel is activated by receptor-induced Ca2+ store depletion of the endoplasmic reticulum (ER) and consists of two transmembrane proteins, STIM1 and Orai1. STIM1 is anchored in the ER membrane and senses changes in the ER luminal Ca2+ concentration. Orai1 is the Ca2+-selective, pore-forming CRAC channel component located in the plasma membrane (PM). Ca2+ store-depletion of the ER triggers activation of STIM1 proteins, which subsequently leads to a conformational change and oligomerization of STIM1 and its coupling to as well as activation of Orai1 channels at the ER-PM contact sites. Although STIM1 and Orai1 are sufficient for CRAC channel activation, their efficient activation and deactivation is fine-tuned by a variety of lipids and lipid- and/or ER-PM junction-dependent accessory proteins. The underlying mechanisms for lipid-mediated CRAC channel modulation as well as the still open questions, are presented in this review.
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14
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de Souza LB, Ong HL, Liu X, Ambudkar IS. PIP 2 and septin control STIM1/Orai1 assembly by regulating cytoskeletal remodeling via a CDC42-WASP/WAVE-ARP2/3 protein complex. Cell Calcium 2021; 99:102475. [PMID: 34601312 DOI: 10.1016/j.ceca.2021.102475] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/08/2021] [Accepted: 09/11/2021] [Indexed: 12/20/2022]
Abstract
Store-operated calcium entry (SOCE) is triggered by assembly of Orai1 with STIM proteins in ER-PM junctions. Plasma membrane PIP2 as well as PIP2-binding protein, SEPT4, significantly impact Orai1-STIM1 interaction. While septins and PIP2 can organize the actin cytoskeleton, it is unclear whether the status of actin within the junctions contributes to SOCE. We report herein that actin remodeling modulates STIM1 clustering. Our findings show that a PIP2- and SEPT4-dependent mechanism involving CDC42, WASP/WAVE, and ARP2 regulates actin remodeling into a ring-like structure around STIM1 puncta. CDC42 localization in the ER-plasma membrane region is enhanced following ER-Ca2+ store depletion. PIP2 depletion or knockdown of SEPT4 attenuate the recruitment of CDC42 to the ER-PM region. Importantly, knockdown of SEPT4, or CDC42+ARP2, disrupts the organization of actin as well as STIM1 clustering. Consequently, Orai1 recruitment to STIM1 puncta, SOCE, and NFAT translocation to the nucleus are all attenuated. Ca2+ influx induced by STIM1-C terminus is not affected by CDC42 knockdown. In aggregate, our findings reveal that PIP2 and SEPT4 affect Orai1/STIM1 clustering by coordinating actin remodeling within ER-PM junctions. This dynamic reorganization of actin has an important role in regulation of SOCE and downstream Ca2+-dependent effector functions.
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Affiliation(s)
- Lorena Brito de Souza
- Secretory Physiology Section, NIDCR, NIH, Bldg. 10/Room 1N-113, Bethesda, MD 20892, USA
| | - Hwei Ling Ong
- Secretory Physiology Section, NIDCR, NIH, Bldg. 10/Room 1N-113, Bethesda, MD 20892, USA.
| | - Xibao Liu
- Secretory Physiology Section, NIDCR, NIH, Bldg. 10/Room 1N-113, Bethesda, MD 20892, USA
| | - Indu S Ambudkar
- Secretory Physiology Section, NIDCR, NIH, Bldg. 10/Room 1N-113, Bethesda, MD 20892, USA.
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15
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Dynes JL, Yeromin AV, Cahalan MD. Cell-wide mapping of Orai1 channel activity reveals functional heterogeneity in STIM1-Orai1 puncta. J Gen Physiol 2021; 152:151900. [PMID: 32589186 PMCID: PMC7478869 DOI: 10.1085/jgp.201812239] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/11/2019] [Accepted: 05/21/2020] [Indexed: 12/16/2022] Open
Abstract
Upon Ca2+ store depletion, Orai1 channels cluster and open at endoplasmic reticulum–plasma membrane (ER–PM) junctions in signaling complexes called puncta. Little is known about whether and how Orai1 channel activity may vary between individual puncta. Previously, we developed and validated optical recording of Orai channel activity, using genetically encoded Ca2+ indicators fused to Orai1 or Orai3 N or C termini. We have now combined total internal reflection fluorescence microscopy with whole-cell recording to map functional properties of channels at individual puncta. After Ca2+ store depletion in HEK cells cotransfected with mCherry-STIM1 and Orai1-GCaMP6f, Orai1-GCaMP6f fluorescence increased progressively with increasingly negative test potentials and robust responses could be recorded from individual puncta. Cell-wide fluorescence half-rise and -fall times during steps to −100 mV test potential indicated probe response times of <50 ms. The in situ Orai1-GCaMP6f affinity for Ca2+ was 620 nM, assessed by monitoring fluorescence using buffered Ca2+ solutions in “unroofed” cells. Channel activity and temporal activation profile were tracked in individual puncta using image maps and automated puncta identification and recording. Simultaneous measurement of mCherry-STIM1 fluorescence uncovered an unexpected gradient in STIM1/Orai1 ratio that extends across the cell surface. Orai1-GCaMP6f channel activity was found to vary across the cell, with inactive channels occurring in the corners of cells where the STIM1/Orai1 ratio was lowest; low-activity channels typically at edges displayed a slow activation phase lasting hundreds of milliseconds. Puncta with high STIM1/Orai1 ratios exhibited a range of channel activity that appeared unrelated to the stoichiometric requirements for gating. These findings demonstrate functional heterogeneity of Orai1 channel activity between individual puncta and establish a new experimental platform that facilitates systematic comparisons between puncta composition and activity.
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Affiliation(s)
- Joseph L Dynes
- Department of Physiology and Biophysics, University of California at Irvine School of Medicine, Irvine, CA
| | - Andriy V Yeromin
- Department of Physiology and Biophysics, University of California at Irvine School of Medicine, Irvine, CA
| | - Michael D Cahalan
- Department of Physiology and Biophysics, University of California at Irvine School of Medicine, Irvine, CA.,Institute for Immunology, University of California, Irvine, Irvine, CA
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16
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KRAP tethers IP 3 receptors to actin and licenses them to evoke cytosolic Ca 2+ signals. Nat Commun 2021; 12:4514. [PMID: 34301929 PMCID: PMC8302619 DOI: 10.1038/s41467-021-24739-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 07/01/2021] [Indexed: 02/06/2023] Open
Abstract
Regulation of IP3 receptors (IP3Rs) by IP3 and Ca2+ allows regenerative Ca2+ signals, the smallest being Ca2+ puffs, which arise from coordinated openings of a few clustered IP3Rs. Cells express thousands of mostly mobile IP3Rs, yet Ca2+ puffs occur at a few immobile IP3R clusters. By imaging cells with endogenous IP3Rs tagged with EGFP, we show that KRas-induced actin-interacting protein (KRAP) tethers IP3Rs to actin beneath the plasma membrane. Loss of KRAP abolishes Ca2+ puffs and the global increases in cytosolic Ca2+ concentration evoked by more intense stimulation. Over-expressing KRAP immobilizes additional IP3R clusters and results in more Ca2+ puffs and larger global Ca2+ signals. Endogenous KRAP determines which IP3Rs will respond: it tethers IP3R clusters to actin alongside sites where store-operated Ca2+ entry occurs, licenses IP3Rs to evoke Ca2+ puffs and global cytosolic Ca2+ signals, implicates the actin cytoskeleton in IP3R regulation and may allow local activation of Ca2+ entry.
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17
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Crul T, Maléth J. Endoplasmic Reticulum-Plasma Membrane Contact Sites as an Organizing Principle for Compartmentalized Calcium and cAMP Signaling. Int J Mol Sci 2021; 22:4703. [PMID: 33946838 PMCID: PMC8124356 DOI: 10.3390/ijms22094703] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/20/2021] [Accepted: 04/27/2021] [Indexed: 01/14/2023] Open
Abstract
In eukaryotic cells, ultimate specificity in activation and action-for example, by means of second messengers-of the myriad of signaling cascades is primordial. In fact, versatile and ubiquitous second messengers, such as calcium (Ca2+) and cyclic adenosine monophosphate (cAMP), regulate multiple-sometimes opposite-cellular functions in a specific spatiotemporal manner. Cells achieve this through segregation of the initiators and modulators to specific plasma membrane (PM) subdomains, such as lipid rafts and caveolae, as well as by dynamic close contacts between the endoplasmic reticulum (ER) membrane and other intracellular organelles, including the PM. Especially, these membrane contact sites (MCSs) are currently receiving a lot of attention as their large influence on cell signaling regulation and cell physiology is increasingly appreciated. Depletion of ER Ca2+ stores activates ER membrane STIM proteins, which activate PM-residing Orai and TRPC Ca2+ channels at ER-PM contact sites. Within the MCS, Ca2+ fluxes relay to cAMP signaling through highly interconnected networks. However, the precise mechanisms of MCS formation and the influence of their dynamic lipid environment on their functional maintenance are not completely understood. The current review aims to provide an overview of our current understanding and to identify open questions of the field.
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Affiliation(s)
- Tim Crul
- First Department of Medicine, University of Szeged, H6720 Szeged, Hungary
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, University of Szeged, H6720 Szeged, Hungary
- HCEMM-SZTE Molecular Gastroenterology Research Group, University of Szeged, H6720 Szeged, Hungary
| | - József Maléth
- First Department of Medicine, University of Szeged, H6720 Szeged, Hungary
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, University of Szeged, H6720 Szeged, Hungary
- HCEMM-SZTE Molecular Gastroenterology Research Group, University of Szeged, H6720 Szeged, Hungary
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18
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Yang X, Annaert W. The Nanoscopic Organization of Synapse Structures: A Common Basis for Cell Communication. MEMBRANES 2021; 11:248. [PMID: 33808285 PMCID: PMC8065904 DOI: 10.3390/membranes11040248] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 03/26/2021] [Accepted: 03/27/2021] [Indexed: 11/16/2022]
Abstract
Synapse structures, including neuronal and immunological synapses, can be seen as the plasma membrane contact sites between two individual cells where information is transmitted from one cell to the other. The distance between the two plasma membranes is only a few tens of nanometers, but these areas are densely populated with functionally different proteins, including adhesion proteins, receptors, and transporters. The narrow space between the two plasma membranes has been a barrier for resolving the synaptic architecture due to the diffraction limit in conventional microscopy (~250 nm). Various advanced super-resolution microscopy techniques, such as stimulated emission depletion (STED), structured illumination microscopy (SIM), and single-molecule localization microscopy (SMLM), bypass the diffraction limit and provide a sub-diffraction-limit resolving power, ranging from 10 to 100 nm. The studies using super-resolution microscopy have revealed unprecedented details of the nanoscopic organization and dynamics of synaptic molecules. In general, most synaptic proteins appear to be heterogeneously distributed and form nanodomains at the membranes. These nanodomains are dynamic functional units, playing important roles in mediating signal transmission through synapses. Herein, we discuss our current knowledge on the super-resolution nanoscopic architecture of synapses and their functional implications, with a particular focus on the neuronal synapses and immune synapses.
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Affiliation(s)
| | - Wim Annaert
- VIB Center for Brain and Disease Research and KU Leuven, Department of Neurosciences, Gasthuisberg, B-3000 Leuven, Belgium;
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19
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Srivastava N, Tauseef M, Amin R, Joshi B, Joshi JC, Kini V, Klomp J, Li W, Knezevic N, Barbera N, Siddiqui S, Obukhov A, Karginov A, Levitan I, Komarova Y, Mehta D. Noncanonical function of long myosin light chain kinase in increasing ER-PM junctions and augmentation of SOCE. FASEB J 2020; 34:12805-12819. [PMID: 32772419 PMCID: PMC7496663 DOI: 10.1096/fj.201902462rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 06/26/2020] [Accepted: 07/16/2020] [Indexed: 12/13/2022]
Abstract
Increased endothelial permeability leads to excessive exudation of plasma proteins and leukocytes in the interstitium, which characterizes several vascular diseases including acute lung injury. The myosin light chain kinase long (MYLK-L) isoform is canonically known to regulate the endothelial permeability by phosphorylating myosin light chain (MLC-P). Compared to the short MYLK isoform, MYLK-L contains an additional stretch of ~919 amino acid at the N-terminus of unknown function. We show that thapsigargin and thrombin-induced SOCE was markedly reduced in Mylk-L-/- endothelial cells (EC) or MYLK-L-depleted human EC. These agonists also failed to increase endothelial permeability in MYLK-L-depleted EC and Mylk-L-/- lungs, thus demonstrating the novel role of MYLK-L-induced SOCE in increasing vascular permeability. MYLK-L augmented SOCE by increasing endoplasmic reticulum (ER)-plasma membrane (PM) junctions and STIM1 translocation to these junctions. Transduction of N-MYLK domain (amino acids 1-919 devoid of catalytic activity) into Mylk-L-/- EC rescued SOCE to the level seen in control EC in a STIM1-dependent manner. N-MYLK-induced SOCE augmented endothelial permeability without MLC-P via an actin-binding motif, DVRGLL. Liposomal-mediated delivery of N-MYLK mutant but not ∆DVRGLL-N-MYLK mutant in Mylk-L-/- mice rescued vascular permeability increase in response to endotoxin, indicating that targeting of DVRGLL motif within MYLK-L may limit SOCE-induced vascular hyperpermeability.
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Affiliation(s)
- Nityanand Srivastava
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Mohammad Tauseef
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
- Department of Pharmaceutical SciencesChicago State University College of PharmacyChicagoILUSA
| | - Ruhul Amin
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Bhagwati Joshi
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Jagdish Chandra Joshi
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Vidisha Kini
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Jennifer Klomp
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Weenan Li
- Department of Cellular and Integrative PhysiologyIndiana University School of MedicineIndianapolisINUSA
| | - Nebojsa Knezevic
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Nicolas Barbera
- Department of MedicineThe Uniiversity of IllinoisChicagoILUSA
| | - Shahid Siddiqui
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Alexander Obukhov
- Department of Cellular and Integrative PhysiologyIndiana University School of MedicineIndianapolisINUSA
| | - Andrei Karginov
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Irena Levitan
- Department of MedicineThe Uniiversity of IllinoisChicagoILUSA
| | - Yulia Komarova
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
| | - Dolly Mehta
- Department of Pharmacology and Center for Lung and Vascular BiologyThe University of Illinois, College of MedicineChicagoILUSA
- Department of Pharmaceutical SciencesChicago State University College of PharmacyChicagoILUSA
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20
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Bozelli JC, Epand RM. Membrane Shape and the Regulation of Biological Processes. J Mol Biol 2020; 432:5124-5136. [DOI: 10.1016/j.jmb.2020.03.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 03/25/2020] [Accepted: 03/27/2020] [Indexed: 01/06/2023]
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21
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Zhang D. Interplay between endoplasmic reticulum membrane contacts and actomyosin cytoskeleton. Cytoskeleton (Hoboken) 2020; 77:241-248. [PMID: 32543125 DOI: 10.1002/cm.21623] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/11/2020] [Accepted: 06/11/2020] [Indexed: 12/13/2022]
Abstract
Eukaryotic membrane-bound organelles, exhibiting distinctive morphologies, dynamics and functions, are interconnected at membrane contact sites (MCSs) through numerous tethering machineries. MCSs are required for many fundamental cellular processes, such as non-vesicular lipid transfer, calcium transport and organelle homeostasis. Actin cytoskeleton and myosin motors are known to dynamically interact with different membrane boundaries, facilitating organelle movements and partitioning. Intriguingly, recent studies have pinpointed a special participation of actomyosin at various MCSs involving the endoplasmic reticulum (ER), the most extensive membranous organelle in the cell. Here, I summarize emerging roles of ER MCSs in modulating actomyosin structures and discuss feedback functions of such actomyosin regulation at these MCSs.
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Affiliation(s)
- Dan Zhang
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore, Singapore
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22
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Zang J, Zhang T, Hussey PJ, Wang P. Light microscopy of the endoplasmic reticulum-membrane contact sites in plants. J Microsc 2020; 280:134-139. [PMID: 32497309 DOI: 10.1111/jmi.12934] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 05/31/2020] [Accepted: 06/02/2020] [Indexed: 12/14/2022]
Abstract
The existence of membrane contact sites (MCS) has been reported in different systems in the past decade, and their importance has been recognised by the cell biology community. Amongst all endomembrane structures, the endoplasmic reticulum (ER) plays vital roles in organising the organelle interaction network with the plasma membrane (PM), Golgi bodies, mitochondria, plastids, endosomes and autophagosomes. A number of methods have been used to study the establishment and functions of these interactions, among them, light microscopy appears to be one of the most effective approaches. Here, we present an overview of the discovery of ER-PM contact sites, and highlight the latest developments in light microscopical-based techniques that can be used for their study.
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Affiliation(s)
- J Zang
- Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, Hubei Province, China
| | - T Zhang
- Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, Hubei Province, China
| | - P J Hussey
- Department of Biosciences, Durham University, Durham, U.K.,Faculty of Science, Department of Experimental Plant Biology, Charles University, Praha 2, Czechia
| | - P Wang
- Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, Hubei Province, China
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23
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Machaca K. Ca 2+ signaling and lipid transfer 'pas a deux' at ER-PM contact sites orchestrate cell migration. Cell Calcium 2020; 89:102226. [PMID: 32505782 DOI: 10.1016/j.ceca.2020.102226] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 05/30/2020] [Accepted: 05/30/2020] [Indexed: 12/13/2022]
Abstract
Contact sites between the endoplasmic reticulum (ER) and plasma membrane (PM) regulate both non-vesicular lipid transfer as well as Ca2+ signaling with multiple interactions between the two pathways. Here I discuss recent findings that offer exciting insights into the role of store-operated Ca2+ entry (SOCE), Oxysterol-binding protein (OSBP)-related proteins ORP3, Arf5 and the Arf GEF IQSec1 in this crosstalk and how they regulate cell migration and focal adhesion disassembly.
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Affiliation(s)
- Khaled Machaca
- Department of Physiology and Biophysics, Ca(2+) Signaling Group, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, PO Box 24144, Doha, Qatar.
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24
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Yan D, Liu Y. Diverse regulation of plasmodesmal architecture facilitates adaptation to phloem translocation. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:2505-2512. [PMID: 31872215 PMCID: PMC7210759 DOI: 10.1093/jxb/erz567] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 12/20/2019] [Indexed: 05/24/2023]
Abstract
The long-distance translocation of nutrients and mobile molecules between different terminals is necessary for plant growth and development. Plasmodesmata-mediated symplastic trafficking plays an important role in accomplishing this task. To facilitate intercellular transport, plants have evolved diverse plasmodesmata with distinct internal architecture at different cell-cell interfaces along the trafficking route. Correspondingly, different underlying mechanisms for regulating plasmodesmal structures have been gradually revealed. In this review, we highlight recent studies on various plasmodesmal architectures, as well as relevant regulators of their de novo formation and transition, responsible for phloem loading, transport, and unloading specifically. We also discuss the interesting but unaddressed questions relating to, and potential studies on, the adaptation of functional plasmodesmal structures.
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Affiliation(s)
- Dawei Yan
- State Key Laboratory of Crop Stress Adaptation and Improvement, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, China
| | - Yao Liu
- State Key Laboratory of Crop Stress Adaptation and Improvement, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, China
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25
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Store-Operated Calcium Channels: From Function to Structure and Back Again. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035055. [PMID: 31570335 DOI: 10.1101/cshperspect.a035055] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Store-operated calcium (Ca2+) entry (SOCE) occurs through a widely distributed family of ion channels activated by the loss of Ca2+ from the endoplasmic reticulum (ER). The best understood of these is the Ca2+ release-activated Ca2+ (CRAC) channel, which is notable for its unique activation mechanism as well as its many essential physiological functions and the diverse pathologies that result from dysregulation. In response to ER Ca2+ depletion, CRAC channels are formed through a diffusion trap mechanism at ER-plasma membrane (PM) junctions, where the ER Ca2+-sensing stromal interaction molecule (STIM) proteins bind and activate hexamers of Orai pore-forming proteins to trigger Ca2+ entry. Cell biological studies are clarifying the architecture of ER-PM junctions, their roles in Ca2+ and lipid transport, and functional interactions with cytoskeletal proteins. Molecular structures of STIM and Orai have inspired a multitude of mutagenesis and electrophysiological studies that reveal potential mechanisms for how STIM is toggled between inactive and active states, how it binds and activates Orai, and the importance of STIM-binding stoichiometry for opening the channel and establishing its signature characteristics of extremely high Ca2+ selectivity and low Ca2+ conductance.
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26
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Huang X, Jiang C, Yu L, Yang A. Current and Emerging Approaches for Studying Inter-Organelle Membrane Contact Sites. Front Cell Dev Biol 2020; 8:195. [PMID: 32292782 PMCID: PMC7118198 DOI: 10.3389/fcell.2020.00195] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/09/2020] [Indexed: 12/24/2022] Open
Abstract
Inter-organelle membrane contact sites (MCSs) are classically defined as areas of close proximity between heterologous membranes and established by specific proteins (termed tethers). The interest on MCSs has rapidly increased in the last years, since MCSs play a crucial role in the transfer of cellular components between different organelles and have been involved in important cellular functions such as apoptosis, organelle division and biogenesis, and cell growth. Recently, an unprecedented depth and breadth in insights into the details of MCSs have been uncovered. On one hand, extensive MCSs (organelles interactome) are revealed by comprehensive analysis of organelle network with high temporal-spatial resolution at the system level. On the other hand, more and more tethers involving in MCSs are identified and further works are focusing on addressing the role of these tethers in regulating the function of MCSs at the molecular level. These enormous progresses largely depend on the powerful approaches, including several different types of microscopies and various biochemical techniques. These approaches have greatly accelerated recent advances in MCSs at the system and molecular level. In this review, we summarize the current and emerging approaches for studying MCSs, such as various microscopies, proximity-driven fluorescent signal generation and proximity-dependent biotinylation. In addition, we highlight the advantages and disadvantages of the techniques to provide a general guidance for the study of MCSs.
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Affiliation(s)
- Xue Huang
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Chen Jiang
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Lihua Yu
- School of Life Sciences, Chongqing University, Chongqing, China
| | - Aimin Yang
- School of Life Sciences, Chongqing University, Chongqing, China
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27
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Endoplasmic reticulum-plasma membrane contacts: Principals of phosphoinositide and calcium signaling. Curr Opin Cell Biol 2020; 63:125-134. [PMID: 32088611 DOI: 10.1016/j.ceb.2020.01.010] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/18/2020] [Accepted: 01/20/2020] [Indexed: 12/29/2022]
Abstract
The endoplasmic reticulum (ER) forms an extensive network of membrane contact sites with intra-cellular organelles and the plasma membrane (PM). Interorganelle contacts have vital roles in membrane lipid and ion dynamics. In particular, ER-PM contacts are integral to numerous inter-cellular and intra-cellular signaling pathways including phosphoinositide lipid and calcium signaling, mechanotransduction, metabolic regulation, and cell stress responses. Accordingly, ER-PM contacts serve important signaling functions in excitable cells including neurons and muscle and endocrine cells. This review highlights recent advances in our understanding of the vital roles for ER-PM contacts in phosphoinositide and calcium signaling and how signaling pathways in turn regulate proteins that form and function at ER-PM contacts.
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28
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Kirmiz M, Gillies TE, Dickson EJ, Trimmer JS. Neuronal ER-plasma membrane junctions organized by Kv2-VAP pairing recruit Nir proteins and affect phosphoinositide homeostasis. J Biol Chem 2019; 294:17735-17757. [PMID: 31594866 DOI: 10.1074/jbc.ra119.007635] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 10/02/2019] [Indexed: 12/21/2022] Open
Abstract
The association of plasma membrane (PM)-localized voltage-gated potassium (Kv2) channels with endoplasmic reticulum (ER)-localized vesicle-associated membrane protein-associated proteins VAPA and VAPB defines ER-PM junctions in mammalian brain neurons. Here, we used proteomics to identify proteins associated with Kv2/VAP-containing ER-PM junctions. We found that the VAP-interacting membrane-associated phosphatidylinositol (PtdIns) transfer proteins PYK2 N-terminal domain-interacting receptor 2 (Nir2) and Nir3 specifically associate with Kv2.1 complexes. When coexpressed with Kv2.1 and VAPA in HEK293T cells, Nir2 colocalized with cell-surface-conducting and -nonconducting Kv2.1 isoforms. This was enhanced by muscarinic-mediated PtdIns(4,5)P2 hydrolysis, leading to dynamic recruitment of Nir2 to Kv2.1 clusters. In cultured rat hippocampal neurons, exogenously expressed Nir2 did not strongly colocalize with Kv2.1, unless exogenous VAPA was also expressed, supporting the notion that VAPA mediates the spatial association of Kv2.1 and Nir2. Immunolabeling signals of endogenous Kv2.1, Nir2, and VAP puncta were spatially correlated in cultured neurons. Fluorescence-recovery-after-photobleaching experiments revealed that Kv2.1, VAPA, and Nir2 have comparable turnover rates at ER-PM junctions, suggesting that they form complexes at these sites. Exogenous Kv2.1 expression in HEK293T cells resulted in significant differences in the kinetics of PtdIns(4,5)P2 recovery following repetitive muscarinic stimulation, with no apparent impact on resting PtdIns(4,5)P2 or PtdIns(4)P levels. Finally, the brains of Kv2.1-knockout mice had altered composition of PtdIns lipids, suggesting a crucial role for native Kv2.1-containing ER-PM junctions in regulating PtdIns lipid metabolism in brain neurons. These results suggest that ER-PM junctions formed by Kv2 channel-VAP pairing regulate PtdIns lipid homeostasis via VAP-associated PtdIns transfer proteins.
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Affiliation(s)
- Michael Kirmiz
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California 95616
| | - Taryn E Gillies
- Department of Bioengineering, Stanford University, Stanford, California 94305
| | - Eamonn J Dickson
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, California 95616
| | - James S Trimmer
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California 95616 .,Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, California 95616
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29
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Szpila M, Walewska A, Sabat-Pośpiech D, Strączyńska P, Ishikawa T, Milewski R, Szczepańska K, Ajduk A. Postovulatory ageing modifies sperm-induced Ca 2+ oscillations in mouse oocytes through a conditions-dependent, multi-pathway mechanism. Sci Rep 2019; 9:11859. [PMID: 31413272 PMCID: PMC6694115 DOI: 10.1038/s41598-019-48281-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 08/01/2019] [Indexed: 02/04/2023] Open
Abstract
Postovulatory ageing of mammalian oocytes occurs between their ovulation and fertilization and has been shown to decrease their developmental capabilities. Aged oocytes display numerous abnormalities, including altered Ca2+ signalling. Fertilization-induced Ca2+ oscillations are essential for activation of the embryonic development, therefore maintaining proper Ca2+ homeostasis is crucial for the oocyte quality. In the present paper, we show that the mechanism underlying age-dependent alterations in the pattern of sperm-triggered Ca2+ oscillations is more complex and multifaceted than previously believed. Using time-lapse imaging accompanied by immunostaining and molecular analyses, we found that postovulatory ageing affects the amount of Ca2+ stored in the cell, expression of Ca2+ pump SERCA2, amount of available ATP and distribution of endoplasmic reticulum and mitochondria in a manner often strongly depending on ageing conditions (in vitro vs. in vivo). Importantly, those changes do not have to be caused by oxidative stress, usually linked with the ageing process, as they occur even if the amount of reactive oxygen species remains low. Instead, our results suggest that aberrations in Ca2+ signalling may be a synergistic result of ageing-related alterations of the cell cycle, cytoskeleton, and mitochondrial functionality.
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Affiliation(s)
- Marcin Szpila
- Department of Embryology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland.,Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106, Warsaw, Poland
| | - Agnieszka Walewska
- Department of Embryology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland.,Laboratory of Intracellular Ion Channels, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Pasteura 3, 02-093, Warsaw, Poland
| | - Dorota Sabat-Pośpiech
- Department of Embryology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland.,Cellular & Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown St, Liverpool, L69 3BX, UK
| | - Patrycja Strączyńska
- Department of Embryology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland.,School of Medicine with the Division of Dentistry in Zabrze, Medical University of Silesia, pl. Traugutta 2, 41-800, Zabrze, Poland
| | - Takao Ishikawa
- Department of Molecular Biology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Robert Milewski
- Department of Statistics and Medical Informatics, Medical University of Bialystok, Szpitalna 37, 15-295, Bialystok, Poland
| | - Katarzyna Szczepańska
- Department of Embryology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Anna Ajduk
- Department of Embryology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland.
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30
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Katz ZB, Zhang C, Quintana A, Lillemeier BF, Hogan PG. Septins organize endoplasmic reticulum-plasma membrane junctions for STIM1-ORAI1 calcium signalling. Sci Rep 2019; 9:10839. [PMID: 31346209 PMCID: PMC6658532 DOI: 10.1038/s41598-019-46862-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 06/28/2019] [Indexed: 12/21/2022] Open
Abstract
ORAI1 Ca2+ channels in the plasma membrane (PM) are gated by STIM1 at endoplasmic reticulum (ER)-PM junctions to effect store-dependent Ca2+ entry into cells, but little is known about how local STIM-ORAI signalling at junctions is coordinated with overall cellular architecture. Filamentous septins can specify cytoskeletal rearrangements and have been found recently to modulate STIM-ORAI signalling. Here we show by super-resolution imaging of ORAI1, STIM1, and septin 4 in living cells that septins facilitate Ca2+ signalling indirectly. Septin 4 does not colocalize preferentially with ORAI1 in resting or stimulated cells, assemble stably at ER-PM junctions, or specify a boundary that directs or confines ORAI1 to junctions. Rather, ORAI1 is recruited to junctions solely through interaction with STIM proteins, while septins regulate the number of ER-PM junctions and enhance STIM1-ORAI1 interactions within junctions. Thus septins communicate with STIM1 and ORAI1 through protein or lipid intermediaries, and are favorably positioned to coordinate Ca2+ signalling with rearrangements in cellular architecture.
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Affiliation(s)
- Zachary B Katz
- Division of Signalling and Gene Expression, La Jolla Institute for Immunology, La Jolla, CA, 92037, USA
- NOMIS Center for Immunobiology and Microbial Pathogenesis & Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA
| | - Chen Zhang
- Division of Signalling and Gene Expression, La Jolla Institute for Immunology, La Jolla, CA, 92037, USA
| | - Ariel Quintana
- Division of Signalling and Gene Expression, La Jolla Institute for Immunology, La Jolla, CA, 92037, USA
- Translational Science Division, Clinical Science Department, Moffitt Cancer Center Magnolia Campus, Tampa, FL, 33612, USA
| | - Björn F Lillemeier
- NOMIS Center for Immunobiology and Microbial Pathogenesis & Waitt Advanced Biophotonics Center, Salk Institute for Biological Studies, La Jolla, CA, 92037, USA.
| | - Patrick G Hogan
- Division of Signalling and Gene Expression, La Jolla Institute for Immunology, La Jolla, CA, 92037, USA.
- Program in Immunology, University of California San Diego, La Jolla, CA, 92037, USA.
- Moores Cancer Center, University of California San Diego, La Jolla, CA, 92093, USA.
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31
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Bozelli JC, Epand RM. Role of membrane shape in regulating the phosphatidylinositol cycle at contact sites. Chem Phys Lipids 2019; 221:24-29. [DOI: 10.1016/j.chemphyslip.2019.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/25/2019] [Accepted: 03/01/2019] [Indexed: 01/09/2023]
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Remodeling of ER-plasma membrane contact sites but not STIM1 phosphorylation inhibits Ca 2+ influx in mitosis. Proc Natl Acad Sci U S A 2019; 116:10392-10401. [PMID: 31064875 PMCID: PMC6535005 DOI: 10.1073/pnas.1821399116] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The mechanisms blocking Ca2+ influx in mitosis are complex and involve a decrease in stable endoplasmic reticulum (ER)–plasma membrane (PM) contact sites and degradation of the ER Ca2+ sensor stromal interaction molecule 1 (STIM1) but not its phosphorylation. This challenges the current view that STIM1 phosphorylation is essential for mitotic store-operated Ca2+ entry inhibition and sheds light on the dynamics of ER–PM contact sites and of Ca2+ influx in mitosis. Store-operated Ca2+ entry (SOCE), mediated by the endoplasmic reticulum (ER) Ca2+ sensor stromal interaction molecule 1 (STIM1) and the plasma membrane (PM) channel Orai1, is inhibited during mitosis. STIM1 phosphorylation has been suggested to mediate this inhibition, but it is unclear whether additional pathways are involved. Here, we demonstrate using various approaches, including a nonphosphorylatable STIM1 knock-in mouse, that STIM1 phosphorylation is not required for SOCE inhibition in mitosis. Rather, multiple pathways converge to inhibit Ca2+ influx in mitosis. STIM1 interacts with the cochaperone BAG3 and localizes to autophagosomes in mitosis, and STIM1 protein levels are reduced. The density of ER–PM contact sites (CSs) is also dramatically reduced in mitosis, thus physically preventing STIM1 and Orai1 from interacting to activate SOCE. Our findings provide insights into ER–PM CS remodeling during mitosis and a mechanistic explanation of the inhibition of Ca2+ influx that is required for cell cycle progression.
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33
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Griesche N, Sanchez G, Hermans C, Idevall-Hagren O. Cortical mitochondria regulate insulin secretion by local Ca 2+ buffering in rodent beta cells. J Cell Sci 2019; 132:jcs.228544. [PMID: 30926624 DOI: 10.1242/jcs.228544] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 03/11/2019] [Indexed: 12/27/2022] Open
Abstract
Mitochondria play an essential role in regulating insulin secretion from beta cells by providing the ATP needed for the membrane depolarization that results in voltage-dependent Ca2+ influx and subsequent insulin granule exocytosis. Ca2+, in turn, is also rapidly taken up by the mitochondria and exerts important feedback regulation of metabolism. The aim of this study was to determine whether the distribution of mitochondria within beta cells is important for the secretory capacity of these cells. We find that cortically localized mitochondria are abundant in rodent beta cells, and that these mitochondria redistribute towards the cell interior following depolarization. The redistribution requires Ca2+-induced remodeling of the cortical F-actin network. Using light-regulated motor proteins, we increased the cortical density of mitochondria twofold and found that this blunted the voltage-dependent increase in cytosolic Ca2+ concentration and suppressed insulin secretion. The activity-dependent changes in mitochondria distribution are likely to be important for the generation of Ca2+ microdomains required for efficient insulin granule release.
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Affiliation(s)
- Nadine Griesche
- Department of Medical Cell Biology, Uppsala University, BMC Box 571, 75123 Uppsala, Sweden
| | - Gonzalo Sanchez
- Department of Medical Cell Biology, Uppsala University, BMC Box 571, 75123 Uppsala, Sweden
| | - Cedric Hermans
- Department of Medical Cell Biology, Uppsala University, BMC Box 571, 75123 Uppsala, Sweden
| | - Olof Idevall-Hagren
- Department of Medical Cell Biology, Uppsala University, BMC Box 571, 75123 Uppsala, Sweden
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34
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E-syt1 Re-arranges STIM1 Clusters to Stabilize Ring-shaped ER-PM Contact Sites and Accelerate Ca 2+ Store Replenishment. Sci Rep 2019; 9:3975. [PMID: 30850711 PMCID: PMC6408583 DOI: 10.1038/s41598-019-40331-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 01/31/2019] [Indexed: 12/02/2022] Open
Abstract
In many non-excitable cells, the depletion of endoplasmic reticulum (ER) Ca2+ stores leads to the dynamic formation of membrane contact sites (MCSs) between the ER and the plasma membrane (PM), which activates the store-operated Ca2+ entry (SOCE) to refill the ER store. Two different Ca2+-sensitive proteins, STIM1 and extended synaptotagmin-1 (E-syt1), are activated during this process. Due to the lack of live cell super-resolution imaging, how MCSs are dynamically regulated by STIM1 and E-syt1 coordinately during ER Ca2+ store depletion and replenishment remain unknown. With home-built super-resolution microscopes that provide superior axial and lateral resolution in live cells, we revealed that extracellular Ca2+ influx via SOCE activated E-syt1s to move towards the PM by ~12 nm. Unexpectedly, activated E-syt1s did not constitute the MCSs per se, but re-arranged neighboring ER structures into ring-shaped MCSs (230~280 nm in diameter) enclosing E-syt1 puncta, which helped to stabilize MCSs and accelerate local ER Ca2+ replenishment. Overall, we have demonstrated different roles of STIM1 and E-syt1 in MCS formation regulation, SOCE activation and ER Ca2+ store replenishment.
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35
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Chen YJ, Quintanilla CG, Liou J. Recent insights into mammalian ER-PM junctions. Curr Opin Cell Biol 2019; 57:99-105. [PMID: 30739879 DOI: 10.1016/j.ceb.2018.12.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 12/21/2018] [Indexed: 11/28/2022]
Abstract
ER-PM junctions are subcellular sites where the endoplasmic reticulum (ER) and the plasma membrane (PM) are kept in close appositions, providing a platform for inter-organelle contact. These membrane contact sites are important for many physiological functions in mammalian cells, including excitation-contraction coupling, store-operated Ca2+ entry, and non-vesicular transfer of lipids between the ER and the PM. Here we review recent insights into the 3D structure and spatial organization of ER-PM junctions in mammalian cells as well as molecular mechanisms underlying the formation and functions of mammalian ER-PM junctions.
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Affiliation(s)
- Yu-Ju Chen
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390, USA
| | | | - Jen Liou
- Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390, USA.
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36
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Affiliation(s)
- Jeremy G Carlton
- Division of Cancer Studies, Guy's Hospital, King's College London, London SE1 1UL, UK .,The Francis Crick Institute, London NW1 1AT, UK
| | - Benoît Kornmann
- Institute of Biochemistry, ETH Zürich, Zürich 8093, Switzerland
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37
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Sun Y, Huang D, Chen X. Dynamic regulation of plasmodesmatal permeability and its application to horticultural research. HORTICULTURE RESEARCH 2019; 6:47. [PMID: 30962940 PMCID: PMC6441653 DOI: 10.1038/s41438-019-0129-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Revised: 01/17/2019] [Accepted: 01/18/2019] [Indexed: 05/10/2023]
Abstract
Effective cell-to-cell communication allows plants to fine-tune their developmental processes in accordance with the prevailing environmental stimuli. Plasmodesmata (PD) are intercellular channels that span the plant cell wall and serve as cytoplasmic bridges to facilitate efficient exchange of signaling molecules between neighboring cells. The identification of PD-associated proteins and the subsequent elucidation of the regulation of PD structure have provided vital insights into the role of PD architecture in enforcing crucial cellular processes, including callose deposition, ER-Golgi-based secretion, cytoskeleton dynamics, membrane lipid raft organization, chloroplast metabolism, and cell wall formation. In this review, we summarize the emerging discoveries from recent studies that elucidated the regulatory mechanisms involved in PD biogenesis and the dynamics of PD opening-closure. Retrospectively, PD-mediated cell-to-cell communication has been implicated in diverse cellular and physiological processes that are fundamental for the development of horticultural plants. The potential application of PD biotechnological engineering represents a powerful approach for improving agronomic traits in horticultural crops in the future.
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Affiliation(s)
- Yanbiao Sun
- College of Life Science and Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Fujian Agriculture and Forestry University, Fuzhou, Fujian China
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, 350002 China
| | - Dingquan Huang
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, 350002 China
| | - Xu Chen
- Haixia Institute of Science and Technology, Horticultural Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou, 350002 China
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38
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Kirmiz M, Palacio S, Thapa P, King AN, Sack JT, Trimmer JS. Remodeling neuronal ER-PM junctions is a conserved nonconducting function of Kv2 plasma membrane ion channels. Mol Biol Cell 2018; 29:2410-2432. [PMID: 30091655 PMCID: PMC6233057 DOI: 10.1091/mbc.e18-05-0337] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The endoplasmic reticulum (ER) and plasma membrane (PM) form junctions crucial to ion and lipid signaling and homeostasis. The Kv2.1 ion channel is localized at ER–PM junctions in brain neurons and is unique among PM proteins in its ability to remodel these specialized membrane contact sites. Here, we show that this function is conserved between Kv2.1 and Kv2.2, which differ in their biophysical properties, modulation, and cellular expression. Kv2.2 ER–PM junctions are present at sites deficient in the actin cytoskeleton, and disruption of the actin cytoskeleton affects their spatial organization. Kv2.2-containing ER–PM junctions overlap with those formed by canonical ER–PM tethers. The ability of Kv2 channels to remodel ER–PM junctions is unchanged by point mutations that eliminate their ion conduction but eliminated by point mutations within the Kv2-specific proximal restriction and clustering (PRC) domain that do not impact their ion channel function. The highly conserved PRC domain is sufficient to transfer the ER–PM junction–remodeling function to another PM protein. Last, brain neurons in Kv2 double-knockout mice have altered ER–PM junctions. Together, these findings demonstrate a conserved in vivo function for Kv2 family members in remodeling neuronal ER–PM junctions that is distinct from their canonical role as ion-conducting channels shaping neuronal excitability.
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Affiliation(s)
- Michael Kirmiz
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, CA 95616
| | - Stephanie Palacio
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, CA 95616
| | - Parashar Thapa
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616
| | - Anna N King
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, CA 95616
| | - Jon T Sack
- Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616.,Department of Anesthesiology and Pain Medicine, University of California, Davis, Davis, CA 95616
| | - James S Trimmer
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, CA 95616.,Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616
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39
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Phospholipid transport protein function at organelle contact sites. Curr Opin Cell Biol 2018; 53:52-60. [PMID: 29859321 PMCID: PMC6141807 DOI: 10.1016/j.ceb.2018.04.011] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 04/12/2018] [Accepted: 04/29/2018] [Indexed: 11/21/2022]
Abstract
Phospholipids are synthesized at the endoplasmic reticulum (ER), the largest membrane bound organelle that forms membrane contact sites (MCS) with almost every other organelle. MCS are locations at which the membrane es of two organelles are closely positioned to provide a microenvironment where proteins in one membrane can interact with the opposite membrane. Thus, MCS provide an ideal location at which lipid transfer proteins (LTPs) can achieve the efficient transfer of individual classes of lipids from the ER to other organelles via non-vesicular transport. Here we provide an overview of emerging findings on the localization and biochemical activity of LTPs at MCS between the ER and other cellular membranes. The localization of LTPs at MCS offers an elegant cell biological solution to tune local lipid composition to ongoing cell physiology.
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