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Sallinger M, Grabmayr H, Humer C, Bonhenry D, Romanin C, Schindl R, Derler I. Activation mechanisms and structural dynamics of STIM proteins. J Physiol 2024; 602:1475-1507. [PMID: 36651592 DOI: 10.1113/jp283828] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 01/11/2023] [Indexed: 01/19/2023] Open
Abstract
The family of stromal interaction molecules (STIM) includes two widely expressed single-pass endoplasmic reticulum (ER) transmembrane proteins and additional splice variants that act as precise ER-luminal Ca2+ sensors. STIM proteins mainly function as one of the two essential components of the so-called Ca2+ release-activated Ca2+ (CRAC) channel. The second CRAC channel component is constituted by pore-forming Orai proteins in the plasma membrane. STIM and Orai physically interact with each other to enable CRAC channel opening, which is a critical prerequisite for various downstream signalling pathways such as gene transcription or proliferation. Their activation commonly requires the emptying of the intracellular ER Ca2+ store. Using their Ca2+ sensing capabilities, STIM proteins confer this Ca2+ content-dependent signal to Orai, thereby linking Ca2+ store depletion to CRAC channel opening. Here we review the conformational dynamics occurring along the entire STIM protein upon store depletion, involving the transition from the quiescent, compactly folded structure into an active, extended state, modulation by a variety of accessory components in the cell as well as the impairment of individual steps of the STIM activation cascade associated with disease.
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Affiliation(s)
- Matthias Sallinger
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Herwig Grabmayr
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Christina Humer
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Daniel Bonhenry
- Center for Nanobiology and Structural Biology, Institute of Microbiology, Academy of Sciences of the Czech Republic, Nove Hrady, Czech Republic
| | - Christoph Romanin
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
| | - Rainer Schindl
- Gottfried Schatz Research Centre, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
| | - Isabella Derler
- Institute of Biophysics, JKU Life Science Center, Johannes Kepler University Linz, Linz, Austria
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2
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Serrano-Novillo C, Estadella I, Navarro-Pérez M, Oliveras A, de Benito-Bueno A, Socuéllamos PG, Bosch M, Coronado MJ, Sastre D, Valenzuela C, Soeller C, Felipe A. Routing of Kv7.1 to endoplasmic reticulum plasma membrane junctions. Acta Physiol (Oxf) 2024; 240:e14106. [PMID: 38282556 DOI: 10.1111/apha.14106] [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: 10/10/2023] [Revised: 11/21/2023] [Accepted: 01/01/2024] [Indexed: 01/30/2024]
Abstract
AIM The voltage-gated Kv7.1 channel, in association with the regulatory subunit KCNE1, contributes to the IKs current in the heart. However, both proteins travel to the plasma membrane using different routes. While KCNE1 follows a classical Golgi-mediated anterograde pathway, Kv7.1 is located in endoplasmic reticulum-plasma membrane junctions (ER-PMjs), where it associates with KCNE1 before being delivered to the plasma membrane. METHODS To characterize the channel routing to these spots we used a wide repertoire of methodologies, such as protein expression analysis (i.e. protein association and biotin labeling), confocal (i.e. immunocytochemistry, FRET, and FRAP), and dSTORM microscopy, transmission electron microscopy, proteomics, and electrophysiology. RESULTS We demonstrated that Kv7.1 targeted ER-PMjs regardless of the origin or architecture of these structures. Kv2.1, a neuronal channel that also contributes to a cardiac action potential, and JPHs, involved in cardiac dyads, increased the number of ER-PMjs in nonexcitable cells, driving and increasing the level of Kv7.1 at the cell surface. Both ER-PMj inducers influenced channel function and dynamics, suggesting that different protein structures are formed. Although exhibiting no physical interaction, Kv7.1 resided in more condensed clusters (ring-shaped) with Kv2.1 than with JPH4. Moreover, we found that VAMPs and AMIGO, which are Kv2.1 ancillary proteins also associated with Kv7.1. Specially, VAP B, showed higher interaction with the channel when ER-PMjs were stimulated by Kv2.1. CONCLUSION Our results indicated that Kv7.1 may bind to different structures of ER-PMjs that are induced by different mechanisms. This variable architecture can differentially affect the fate of cardiac Kv7.1 channels.
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Affiliation(s)
- Clara Serrano-Novillo
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Irene Estadella
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - María Navarro-Pérez
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Anna Oliveras
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
- Berlin Institute of Medical Systems Biology (BIMSB), Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | | | - Paula G Socuéllamos
- Instituto de Investigaciones Biomédicas Alberto Sols CSIC-UAM, Madrid, Spain
| | - Manel Bosch
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
- Scientific and Technological Centers (CCiTUB), Universitat de Barcelona, Barcelona, Spain
| | - María José Coronado
- Unidad de Microscopía Confocal, Instituto de Investigación Sanitaria Puerta de Hierro-Segovia de Arana (IDIPHISA), Hospital Universitario Puerta de Hierro, Madrid, Spain
| | - Daniel Sastre
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Carmen Valenzuela
- Instituto de Investigaciones Biomédicas Alberto Sols CSIC-UAM, Madrid, Spain
| | | | - Antonio Felipe
- Molecular Physiology Laboratory, Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina (IBUB), Universitat de Barcelona, Barcelona, Spain
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3
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Hall DD, Takeshima H, Song LS. Structure, Function, and Regulation of the Junctophilin Family. Annu Rev Physiol 2024; 86:123-147. [PMID: 37931168 PMCID: PMC10922073 DOI: 10.1146/annurev-physiol-042022-014926] [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] [Indexed: 11/08/2023]
Abstract
In both excitable and nonexcitable cells, diverse physiological processes are linked to different calcium microdomains within nanoscale junctions that form between the plasma membrane and endo-sarcoplasmic reticula. It is now appreciated that the junctophilin protein family is responsible for establishing, maintaining, and modulating the structure and function of these junctions. We review foundational findings from more than two decades of research that have uncovered how junctophilin-organized ultrastructural domains regulate evolutionarily conserved biological processes. We discuss what is known about the junctophilin family of proteins. Our goal is to summarize the current knowledge of junctophilin domain structure, function, and regulation and to highlight emerging avenues of research that help our understanding of the transcriptional, translational, and post-translational regulation of this gene family and its roles in health and during disease.
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Affiliation(s)
- Duane D Hall
- Department of Internal Medicine, Division of Cardiovascular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA; ,
| | - Hiroshi Takeshima
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, Japan
| | - Long-Sheng Song
- Department of Internal Medicine, Division of Cardiovascular Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA; ,
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
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4
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Sun S, Zhao G, Jia M, Jiang Q, Li S, Wang H, Li W, Wang Y, Bian X, Zhao YG, Huang X, Yang G, Cai H, Pastor-Pareja JC, Ge L, Zhang C, Hu J. Stay in touch with the endoplasmic reticulum. SCIENCE CHINA. LIFE SCIENCES 2024; 67:230-257. [PMID: 38212460 DOI: 10.1007/s11427-023-2443-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Accepted: 08/28/2023] [Indexed: 01/13/2024]
Abstract
The endoplasmic reticulum (ER), which is composed of a continuous network of tubules and sheets, forms the most widely distributed membrane system in eukaryotic cells. As a result, it engages a variety of organelles by establishing membrane contact sites (MCSs). These contacts regulate organelle positioning and remodeling, including fusion and fission, facilitate precise lipid exchange, and couple vital signaling events. Here, we systematically review recent advances and converging themes on ER-involved organellar contact. The molecular basis, cellular influence, and potential physiological functions for ER/nuclear envelope contacts with mitochondria, Golgi, endosomes, lysosomes, lipid droplets, autophagosomes, and plasma membrane are summarized.
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Affiliation(s)
- Sha Sun
- National Laboratory of Biomacromolecules, Institute of Biophysics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Gan Zhao
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Mingkang Jia
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Qing Jiang
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, 100871, China
| | - Shulin Li
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Haibin Wang
- National Laboratory of Biomacromolecules, Institute of Biophysics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China
| | - Wenjing Li
- Laboratory of Computational Biology & Machine Intelligence, School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yunyun Wang
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China
| | - Xin Bian
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, 300071, China.
| | - Yan G Zhao
- Brain Research Center, Department of Biology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, 518055, China.
| | - Xun Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Ge Yang
- Laboratory of Computational Biology & Machine Intelligence, School of Artificial Intelligence, University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Huaqing Cai
- National Laboratory of Biomacromolecules, Institute of Biophysics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Jose C Pastor-Pareja
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Institute of Neurosciences, Consejo Superior de Investigaciones Cientfflcas-Universidad Miguel Hernandez, San Juan de Alicante, 03550, Spain.
| | - Liang Ge
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
| | - Chuanmao Zhang
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation, College of Life Sciences, Peking University, Beijing, 100871, China.
| | - Junjie Hu
- National Laboratory of Biomacromolecules, Institute of Biophysics, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101, China.
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5
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Kichuk T, Dhamankar S, Malani S, Hofstadter WA, Wegner SA, Cristea IM, Avalos JL. Using MitER for 3D analysis of mitochondrial morphology and ER contacts. CELL REPORTS METHODS 2024; 4:100692. [PMID: 38232737 PMCID: PMC10832265 DOI: 10.1016/j.crmeth.2023.100692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Revised: 09/13/2023] [Accepted: 12/22/2023] [Indexed: 01/19/2024]
Abstract
We have developed an open-source workflow that allows for quantitative single-cell analysis of organelle morphology, distribution, and inter-organelle contacts with an emphasis on the analysis of mitochondria and mitochondria-endoplasmic reticulum (mito-ER) contact sites. As the importance of inter-organelle contacts becomes more widely recognized, there is a concomitant increase in demand for tools to analyze subcellular architecture. Here, we describe a workflow we call MitER (pronounced "mightier"), which allows for automated calculation of organelle morphology, distribution, and inter-organelle contacts from 3D renderings by employing the animation software Blender. We then use MitER to quantify the variations in the mito-ER networks of Saccharomyces cerevisiae, revealing significantly more mito-ER contacts within respiring cells compared to fermenting cells. We then demonstrate how this workflow can be applied to mammalian systems and used to monitor mitochondrial dynamics and inter-organelle contact in time-lapse studies.
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Affiliation(s)
- Therese Kichuk
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Satyen Dhamankar
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | - Saurabh Malani
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA
| | | | - Scott A Wegner
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Ileana M Cristea
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - José L Avalos
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ 08544, USA; The Andlinger Center for Energy and the Environment, Princeton University, Princeton, NJ 08544, USA; High Meadows Environmental Institute, Princeton University, Princeton, NJ 08544, USA; Omenn-Darling Bioengineering Institute, Princeton University, Princeton, NJ 08544, USA.
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6
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Fameli N, van Breemen C, Groschner K. Nanojunctions: Specificity of Ca 2+ signaling requires nano-scale architecture of intracellular membrane contact sites. Cell Calcium 2024; 117:102837. [PMID: 38011822 DOI: 10.1016/j.ceca.2023.102837] [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: 07/25/2023] [Revised: 10/31/2023] [Accepted: 11/17/2023] [Indexed: 11/29/2023]
Abstract
Spatio-temporal definition of Ca2+ signals involves the assembly of signaling complexes within the nano-architecture of contact sites between the sarco/endoplasmic reticulum (SR/ER) and the plasma membrane (PM). While the requirement of precise spatial assembly and positioning of the junctional signaling elements is well documented, the role of the nano-scale membrane architecture itself, as an ion-reflecting confinement of the signalling unit, remains as yet elusive. Utilizing the Na+/Ca2+ Exchanger-1 / SR/ER Ca2+ ATPase-2-mediated ER Ca2+ refilling process as a junctional signalling paradigm, we provide here the first evidence for an indispensable cellular function of the junctional membrane architecture. Our stochastic modeling approach demonstrates that junctional ER Ca2+ refilling operates exclusively at nano-scale membrane spacing, with a strong inverse relationship between junctional width and signaling efficiency. Our model predicts a breakdown of junctional Ca2+ signaling with loss of reflecting membrane confinement. In addition we consider interactions between Ca2+ and the phospholipid membrane surface, which may support interfacial Ca2+ transport and promote receptor targeting. Alterations in the molecular and nano-scale membrane organization at organelle-PM contacts are suggested as a new concept in pathophysiology.
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Affiliation(s)
| | - Cornelis van Breemen
- Department of Anesthesiology, Pharmacology, and Therapeutics, The University of British Columbia, Vancouver, British Columbia, Canada
| | - Klaus Groschner
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Graz, Austria.
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7
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Johnson B, Iuliano M, Lam T, Biederer T, De Camilli P. A complex of the lipid transport ER proteins TMEM24 and C2CD2 with band 4.1 at cell-cell contacts. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.06.570396. [PMID: 38106008 PMCID: PMC10723409 DOI: 10.1101/2023.12.06.570396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2023]
Abstract
Junctions between the ER and the plasma membrane (ER/PM junctions) are implicated in calcium homeostasis, non-vesicular lipid transfer and other cellular functions. Two ER proteins that function both as membrane tethers to the PM via a polybasic motif in their C-terminus and as phospholipid transporters are brain-enriched TMEM24 (C2CD2L) and its paralog C2CD2. Based on an unbiased proximity ligation analysis, we found that both proteins can also form a complex with band 4.1 family members, which in turn can bind a variety of plasma membrane proteins including cell adhesion molecules such as SynCAM 1. This complex results in the enrichment of TMEM24 and C2CD2 containing ER/PM junctions at sites of cell contacts. Dynamic properties of TMEM24-dependent ER/PM contacts are impacted when in complex as TMEM24 present at cell adjacent junctions is not shed by calcium rise, unlike TMEM24 at non-cell adjacent junctions. These findings suggest that cell-contact interactions control ER/PM junctions via TMEM24 complexes involving band 4.1 proteins.
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Affiliation(s)
- Ben Johnson
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Maria Iuliano
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111
| | - TuKiet Lam
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Keck MS and Proteomics Resource, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Thomas Biederer
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Department of Neurology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Pietro De Camilli
- Department of Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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8
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Qiu C, Xia F, Zhang J, Shi Q, Meng Y, Wang C, Pang H, Gu L, Xu C, Guo Q, Wang J. Advanced Strategies for Overcoming Endosomal/Lysosomal Barrier in Nanodrug Delivery. RESEARCH (WASHINGTON, D.C.) 2023; 6:0148. [PMID: 37250954 PMCID: PMC10208951 DOI: 10.34133/research.0148] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 04/27/2023] [Indexed: 05/31/2023]
Abstract
Nanocarriers have therapeutic potential to facilitate drug delivery, including biological agents, small-molecule drugs, and nucleic acids. However, their efficiency is limited by several factors; among which, endosomal/lysosomal degradation after endocytosis is the most important. This review summarizes advanced strategies for overcoming endosomal/lysosomal barriers to efficient nanodrug delivery based on the perspective of cellular uptake and intracellular transport mechanisms. These strategies include promoting endosomal/lysosomal escape, using non-endocytic methods of delivery to directly cross the cell membrane to evade endosomes/lysosomes and making a detour pathway to evade endosomes/lysosomes. On the basis of the findings of this review, we proposed several promising strategies for overcoming endosomal/lysosomal barriers through the smarter and more efficient design of nanodrug delivery systems for future clinical applications.
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Affiliation(s)
- Chong Qiu
- Artemisinin Research Center, and Institute of Chinese Materia Medica,
China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Fei Xia
- Artemisinin Research Center, and Institute of Chinese Materia Medica,
China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Junzhe Zhang
- Artemisinin Research Center, and Institute of Chinese Materia Medica,
China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Qiaoli Shi
- Artemisinin Research Center, and Institute of Chinese Materia Medica,
China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Yuqing Meng
- Artemisinin Research Center, and Institute of Chinese Materia Medica,
China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Chen Wang
- Artemisinin Research Center, and Institute of Chinese Materia Medica,
China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Huanhuan Pang
- Artemisinin Research Center, and Institute of Chinese Materia Medica,
China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Liwei Gu
- Artemisinin Research Center, and Institute of Chinese Materia Medica,
China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Chengchao Xu
- Artemisinin Research Center, and Institute of Chinese Materia Medica,
China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Qiuyan Guo
- Artemisinin Research Center, and Institute of Chinese Materia Medica,
China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Jigang Wang
- Artemisinin Research Center, and Institute of Chinese Materia Medica,
China Academy of Chinese Medical Sciences, Beijing 100700, China
- Department of Nephrology, and Shenzhen Clinical Research Centre for Geriatrics, Shenzhen People's Hospital, The First Affiliated Hospital,
Southern University of Science and Technology, Shenzhen, Guangdong 518020, China
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9
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Carreras-Sureda A, Henry C, Demaurex N. Extending the Contacts Breaks the Flow. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2023; 6:25152564221125045. [PMID: 37366412 PMCID: PMC10243554 DOI: 10.1177/25152564221125045] [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] [Indexed: 06/28/2023]
Abstract
In this news and views, we discuss our recent publication where we described how ER-PM membrane contact sites (MCS) are modulated during store operated calcium entry (SOCE). We also examine why enforcing ER-PM MCS by tethering proteins does not not enhance, but rather inhibits SOCE.
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Affiliation(s)
- Amado Carreras-Sureda
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Christopher Henry
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Nicolas Demaurex
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
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10
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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: 3] [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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11
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Yu L, Hall DD, Zhao W, Song LS. NMR resonance assignments of the DNA binding domain of mouse Junctophilin-2. BIOMOLECULAR NMR ASSIGNMENTS 2022; 16:273-279. [PMID: 35665900 PMCID: PMC10394741 DOI: 10.1007/s12104-022-10091-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/06/2022] [Indexed: 06/15/2023]
Abstract
Junctophilin-2 (JP2) is a critical structural protein in the heart by stabilizing junctional membrane complexes between the plasma membrane and sarcoplasmic reticula responsible for precise Ca2+ regulation. Such complexes are essential for efficient cardiomyocyte contraction and adaptation to altered cardiac workload conditions. Mutations in the JPH2 gene that encodes JP2 are associated with inherited cardiomyopathies and arrhythmias, and disruption of JP2 function is lethal. Interestingly, cardiac stress promotes the proteolytic cleavage of JP2 that triggers the translocation of its N-terminal fragment into the nucleus to repress maladaptive gene transcription. We previously found that the central region of JP2 is responsible for mediating direct DNA binding interactions. Recent structural studies indicate that this region serves as a structural role in the cytosolic form of JP2 by folding into a single continuous α-helix. However, the structural basis of how this DNA-binding domain interacts with DNA is not known. Here, we report the backbone and sidechain assignments of the DNA-binding domain (residues 331-413) of mouse JP2. These assignments reveal that the JP2 DNA binding domain is an intrinsically disordered protein and contains two α-helices located in the C-terminal portion of the protein. Moreover, this protein binds to DNA in a similar manner to that shown previously by electrophoretic mobility shift assays. Therefore, these assignments provide a framework for further structural studies into the interaction of this JP2 domain with DNA for the elucidation of transcriptional regulation of stress-responsive genes as well as its role in the stabilization of junctional membrane complexes.
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Affiliation(s)
- Liping Yu
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, B291, CBRB, 285 Newton Road, Iowa City, IA, 52242, USA.
- CCOM NMR Core Facility, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA.
| | - Duane D Hall
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, 285 Newton Road, Iowa City, IA, 52242, USA
| | - Weiyang Zhao
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, 285 Newton Road, Iowa City, IA, 52242, USA
| | - Long-Sheng Song
- Department of Biochemistry and Molecular Biology, Carver College of Medicine, University of Iowa, B291, CBRB, 285 Newton Road, Iowa City, IA, 52242, USA.
- Department of Internal Medicine, Carver College of Medicine, University of Iowa, 285 Newton Road, Iowa City, IA, 52242, USA.
- Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA.
- Iowa City Veterans Affairs Medical Center, Iowa City, IA, 52242, USA.
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12
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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: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [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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13
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Kai F, Ou G, Tourdot RW, Stashko C, Gaietta G, Swift MF, Volkmann N, Long AF, Han Y, Huang HH, Northey JJ, Leidal AM, Viasnoff V, Bryant DM, Guo W, Wiita AP, Guo M, Dumont S, Hanein D, Radhakrishnan R, Weaver VM. ECM dimensionality tunes actin tension to modulate endoplasmic reticulum function and spheroid phenotypes of mammary epithelial cells. EMBO J 2022; 41:e109205. [PMID: 35880301 PMCID: PMC9434103 DOI: 10.15252/embj.2021109205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 06/17/2022] [Accepted: 06/22/2022] [Indexed: 12/11/2022] Open
Abstract
Patient-derived organoids and cellular spheroids recapitulate tissue physiology with remarkable fidelity. We investigated how engagement with a reconstituted basement membrane in three dimensions (3D) supports the polarized, stress resilient tissue phenotype of mammary epithelial spheroids. Cells interacting with reconstituted basement membrane in 3D had reduced levels of total and actin-associated filamin and decreased cortical actin tension that increased plasma membrane protrusions to promote negative plasma membrane curvature and plasma membrane protein associations linked to protein secretion. By contrast, cells engaging a reconstituted basement membrane in 2D had high cortical actin tension that forced filamin unfolding and endoplasmic reticulum (ER) associations. Enhanced filamin-ER interactions increased levels of PKR-like ER kinase effectors and ER-plasma membrane contact sites that compromised calcium homeostasis and diminished cell viability. Consequently, cells with decreased cortical actin tension had reduced ER stress and survived better. Consistently, cortical actin tension in cellular spheroids regulated polarized basement membrane membrane deposition and sensitivity to exogenous stress. The findings implicate cortical actin tension-mediated filamin unfolding in ER function and underscore the importance of tissue mechanics in organoid homeostasis.
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Affiliation(s)
- FuiBoon Kai
- Department of Surgery, Center for Bioengineering and Tissue RegenerationUniversity of California San FranciscoSan FranciscoCAUSA
| | - Guanqing Ou
- Department of Surgery, Center for Bioengineering and Tissue RegenerationUniversity of California San FranciscoSan FranciscoCAUSA
| | - Richard W Tourdot
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPAUSA
- Department of Chemical and Biomolecular EngineeringUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Connor Stashko
- Department of Surgery, Center for Bioengineering and Tissue RegenerationUniversity of California San FranciscoSan FranciscoCAUSA
| | | | | | - Niels Volkmann
- Scintillon InstituteSan DiegoCAUSA
- Structural Image Analysis Unit, Department of Structural Biology and Chemistry, Institut PasteurUniversité Paris Cité, CNRS UMR3528ParisFrance
| | - Alexandra F Long
- Tetrad Graduate ProgramUniversity of California San FranciscoSan FranciscoCAUSA
- Department of Bioengineering and Therapeutic SciencesDepartment of Cell & Tissue Biology, University of California San FranciscoSan FranciscoCAUSA
| | - Yulong Han
- Department of Mechanical EngineeringMassachusetts Institute of TechnologyCambridgeMAUSA
| | - Hector H Huang
- Department of Laboratory MedicineUniversity of California San FranciscoSan FranciscoCAUSA
| | - Jason J Northey
- Department of Surgery, Center for Bioengineering and Tissue RegenerationUniversity of California San FranciscoSan FranciscoCAUSA
| | - Andrew M Leidal
- Department of PathologyUniversity of California San FranciscoSan FranciscoCAUSA
| | - Virgile Viasnoff
- Mechanobiology InstituteNational University of SingaporeSingapore CitySingapore
| | | | - Wei Guo
- Department of BiologyUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Arun P Wiita
- Department of Laboratory MedicineUniversity of California San FranciscoSan FranciscoCAUSA
| | - Ming Guo
- Department of Mechanical EngineeringMassachusetts Institute of TechnologyCambridgeMAUSA
| | - Sophie Dumont
- Department of Bioengineering and Therapeutic SciencesDepartment of Cell & Tissue Biology, University of California San FranciscoSan FranciscoCAUSA
- Chan Zuckerberg BiohubSan FranciscoCAUSA
| | - Dorit Hanein
- Scintillon InstituteSan DiegoCAUSA
- Structural Studies of Macromolecular Machines in Cellulo Unit, Department of Structural Biology and Chemistry, Institut PasteurUniversité Paris Cité, CNRS UMR3528ParisFrance
| | - Ravi Radhakrishnan
- Department of BioengineeringUniversity of PennsylvaniaPhiladelphiaPAUSA
- Department of Chemical and Biomolecular EngineeringUniversity of PennsylvaniaPhiladelphiaPAUSA
| | - Valerie M Weaver
- Department of Surgery, Center for Bioengineering and Tissue RegenerationUniversity of California San FranciscoSan FranciscoCAUSA
- Departments of Radiation Oncology and Bioengineering and Therapeutic Sciences, Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell ResearchUniversity of California San FranciscoSan FranciscoCAUSA
- UCSF Helen Diller Family Comprehensive Cancer CenterUniversity of California San FranciscoSan FranciscoCAUSA
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14
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Thomas FB, Omnus DJ, Bader JM, Chung GH, Kono N, Stefan CJ. Tricalbin proteins regulate plasma membrane phospholipid homeostasis. Life Sci Alliance 2022; 5:5/8/e202201430. [PMID: 35440494 PMCID: PMC9018018 DOI: 10.26508/lsa.202201430] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 04/03/2022] [Accepted: 04/04/2022] [Indexed: 12/26/2022] Open
Abstract
The evolutionarily conserved extended synaptotagmin (E-Syt) proteins are calcium-activated lipid transfer proteins that function at contacts between the ER and plasma membrane (ER-PM contacts). However, roles of the E-Syt family members in PM lipid organisation remain incomplete. Among the E-Syt family, the yeast tricalbin (Tcb) proteins are essential for PM integrity upon heat stress, but it is not known how they contribute to PM maintenance. Using quantitative lipidomics and microscopy, we find that the Tcb proteins regulate phosphatidylserine homeostasis at the PM. Moreover, upon heat-induced membrane stress, Tcb3 co-localises with the PM protein Sfk1 that is implicated in PM phospholipid asymmetry and integrity. The Tcb proteins also control the PM targeting of the known phosphatidylserine effector Pkc1 upon heat-induced stress. Phosphatidylserine has evolutionarily conserved roles in PM organisation, integrity, and repair. We propose that phospholipid regulation is an ancient essential function of E-Syt family members required for PM integrity.
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Affiliation(s)
- Ffion B Thomas
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Deike J Omnus
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Jakob M Bader
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Gary Hc Chung
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK
| | - Nozomu Kono
- Department of Health Chemistry, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Christopher J Stefan
- Medical Research Council Laboratory for Molecular Cell Biology, University College London, London, UK
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15
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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: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 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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16
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Krishnan V, Ali S, Gonzales AL, Thakore P, Griffin CS, Yamasaki E, Alvarado MG, Johnson MT, Trebak M, Earley S. STIM1-dependent peripheral coupling governs the contractility of vascular smooth muscle cells. eLife 2022; 11:70278. [PMID: 35147077 PMCID: PMC8947769 DOI: 10.7554/elife.70278] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 02/10/2022] [Indexed: 11/28/2022] Open
Abstract
Peripheral coupling between the sarcoplasmic reticulum (SR) and plasma membrane (PM) forms signaling complexes that regulate the membrane potential and contractility of vascular smooth muscle cells (VSMCs). The mechanisms responsible for these membrane interactions are poorly understood. In many cells, STIM1 (stromal interaction molecule 1), a single-transmembrane-domain protein that resides in the endoplasmic reticulum (ER), transiently moves to ER-PM junctions in response to depletion of ER Ca2+ stores and initiates store-operated Ca2+ entry (SOCE). Fully differentiated VSMCs express STIM1 but exhibit only marginal SOCE activity. We hypothesized that STIM1 is constitutively active in contractile VSMCs and maintains peripheral coupling. In support of this concept, we found that the number and size of SR-PM interacting sites were decreased, and SR-dependent Ca2+-signaling processes were disrupted in freshly isolated cerebral artery SMCs from tamoxifen-inducible, SMC-specific STIM1-knockout (Stim1-smKO) mice. VSMCs from Stim1-smKO mice also exhibited a reduction in nanoscale colocalization between Ca2+-release sites on the SR and Ca2+-activated ion channels on the PM, accompanied by diminished channel activity. Stim1-smKO mice were hypotensive, and resistance arteries isolated from them displayed blunted contractility. These data suggest that STIM1 – independent of SR Ca2+ store depletion – is critically important for stable peripheral coupling in contractile VSMCs.
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Affiliation(s)
- Vivek Krishnan
- Department of Pharmacology, University of Nevada Reno, Reno, United States
| | - Sher Ali
- Department of Pharmacology, University of Nevada Reno, Reno, United States
| | - Albert L Gonzales
- Department of Physiology and Cell Biology, University of Nevada Reno, Reno, United States
| | - Pratish Thakore
- Department of Pharmacology, University of Nevada, Reno, Reno, United States
| | - Caoimhin S Griffin
- Department of Pharmacology, University of Nevada Reno, Reno, United States
| | - Evan Yamasaki
- Department of Pharmacology, University of Nevada Reno, Reno, United States
| | - Michael G Alvarado
- Department of Pharmacology, University of Nevada Reno, Reno, United States
| | - Martin T Johnson
- Department of Cellular and Molecular Physiology, Penn State University, Hershey, United States
| | - Mohamed Trebak
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, United States
| | - Scott Earley
- Department of Pharmacology, University of Nevada Reno, Reno, United States
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17
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Quintanilla CG, Lee WR, Liou J. Nir1 constitutively localizes at ER-PM junctions and promotes Nir2 recruitment for PIP 2 homeostasis. Mol Biol Cell 2022; 33:br2. [PMID: 35020418 PMCID: PMC9250379 DOI: 10.1091/mbc.e21-07-0356] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Homeostatic regulation of plasma membrane (PM) phosphatidylinositol 4,5-bisphosphate (PIP2) in receptor-stimulated cells is mediated by the lipid transfer protein Nir2. Nir2 is dynamically recruited to endoplasmic reticulum–plasma membrane (ER–PM) junctions to facilitate replenishment of PM PIP2 hydrolyzed during receptor-mediated signaling. However, our knowledge regarding the activation and sustainment of Nir2-mediated replenishment of PM PIP2 is limited. Here, we describe the functions of Nir1 as a positive regulator of Nir2 and PIP2 homeostasis. In contrast to the family proteins Nir2 and Nir3, Nir1 constitutively localizes at ER–PM junctions. Nir1 potentiates Nir2 targeting to ER–PM junctions during receptor-mediated signaling and is required for efficient PM PIP2 replenishment. Live-cell imaging and biochemical analysis reveal that Nir1 interacts with Nir2 via a region between the FFAT motif and the DDHD domain. Combined, results from this study identify Nir1 as an ER–PM junction localized protein that promotes Nir2 recruitment for PIP2 homeostasis.
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Affiliation(s)
| | - Wan-Ru Lee
- Department of Physiology, UT Southwestern Medical Center, TX 75390, USA
| | - Jen Liou
- Department of Physiology, UT Southwestern Medical Center, TX 75390, USA
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18
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Fountain A, Inpanathan S, Alves P, Verdawala MB, Botelho RJ. Phagosome maturation in macrophages: Eat, digest, adapt, and repeat. Adv Biol Regul 2021; 82:100832. [PMID: 34717137 DOI: 10.1016/j.jbior.2021.100832] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 10/06/2021] [Indexed: 11/30/2022]
Abstract
Phagocytosis is a dynamic process that requires an intricate interplay between phagocytic receptors, membrane lipids, and numerous signalling proteins and their effectors, to coordinate the engulfment of a bound particle. These particles are diverse in their physico-chemical properties such as size and shape and include bacteria, fungi, apoptotic cells, living tumour cells, and abiotic particles. Once engulfed, these particles are enclosed within a phagosome, which undergoes a striking transformation referred to as phagosome maturation, which will ultimately lead to the processing and degradation of the enclosed particulate. In this review, we focus on recent advancements in phagosome maturation in macrophages, highlighting new discoveries and emerging themes. Such advancements include identification of new GTPases and their effectors and the intricate spatio-temporal dynamics of phosphoinositides in governing phagosome maturation. We then explore phagosome fission and recycling, the emerging role of membrane contact sites, and delve into mechanisms of phagosome resolution to recycle and reform lysosomes. We further illustrate how phagosome maturation is context-dependent, subject to the type of particle, phagocytic receptors, the phagocytes and their state of activation during phagocytosis. Lastly, we discuss how phagosomes serve as signalling platforms to help phagocytes adapt to their environmental conditions. Overall, this review aims to cover recent findings, identify emerging themes, and highlight current challenges and directions to improve our understanding of phagosome maturation in macrophages.
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Affiliation(s)
- Aaron Fountain
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada; Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada
| | - Subothan Inpanathan
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada; Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada
| | - Patris Alves
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada; Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada
| | - Munira B Verdawala
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada
| | - Roberto J Botelho
- Department of Chemistry and Biology and Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada; Graduate Program in Molecular Science, Ryerson University, Toronto, Ontario, M5B2K3, Canada.
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19
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Hassan Z, Kumar ND, Reggiori F, Khan G. How Viruses Hijack and Modify the Secretory Transport Pathway. Cells 2021; 10:2535. [PMID: 34685515 PMCID: PMC8534161 DOI: 10.3390/cells10102535] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/28/2021] [Accepted: 09/06/2021] [Indexed: 12/23/2022] Open
Abstract
Eukaryotic cells contain dynamic membrane-bound organelles that are constantly remodeled in response to physiological and environmental cues. Key organelles are the endoplasmic reticulum, the Golgi apparatus and the plasma membrane, which are interconnected by vesicular traffic through the secretory transport route. Numerous viruses, especially enveloped viruses, use and modify compartments of the secretory pathway to promote their replication, assembly and cell egression by hijacking the host cell machinery. In some cases, the subversion mechanism has been uncovered. In this review, we summarize our current understanding of how the secretory pathway is subverted and exploited by viruses belonging to Picornaviridae, Coronaviridae, Flaviviridae,Poxviridae, Parvoviridae and Herpesviridae families.
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Affiliation(s)
- Zubaida Hassan
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain P.O. Box 17666, United Arab Emirates;
- Department of Microbiology, School of Life Sciences, Modibbo Adama University, Yola PMB 2076, Nigeria
| | - Nilima Dinesh Kumar
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands; (N.D.K.); (F.R.)
- Department of Medical Microbiology and Infection Prevention, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, 9713 AV Groningen, The Netherlands; (N.D.K.); (F.R.)
| | - Gulfaraz Khan
- Department of Medical Microbiology and Immunology, College of Medicine and Health Sciences, United Arab Emirates University, Al Ain P.O. Box 17666, United Arab Emirates;
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20
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Zhang JF, Mehta S, Zhang J. Signaling Microdomains in the Spotlight: Visualizing Compartmentalized Signaling Using Genetically Encoded Fluorescent Biosensors. Annu Rev Pharmacol Toxicol 2021; 61:587-608. [PMID: 33411579 DOI: 10.1146/annurev-pharmtox-010617-053137] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
How cells muster a network of interlinking signaling pathways to faithfully convert diverse external cues to specific functional outcomes remains a central question in biology. Through their ability to convert dynamic biochemical activities to rapid and precise optical readouts, genetically encoded fluorescent biosensors have become instrumental in unraveling the molecular logic controlling the specificity of intracellular signaling. In this review, we discuss how the use of genetically encoded fluorescent biosensors to visualize dynamic signaling events within their native cellular context is elucidating the different strategies employed by cells to organize signaling activities into discrete compartments, or signaling microdomains, to ensure functional specificity.
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Affiliation(s)
- Jin-Fan Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, USA; .,Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Sohum Mehta
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, USA;
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, California 92093, USA; .,Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, USA.,Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, California 92093, USA
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21
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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: 1.7] [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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22
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Bardsley OJ, Matthews HR, Huang CLH. Finite element analysis predicts Ca 2+ microdomains within tubular-sarcoplasmic reticular junctions of amphibian skeletal muscle. Sci Rep 2021; 11:14376. [PMID: 34257321 PMCID: PMC8277803 DOI: 10.1038/s41598-021-93083-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/14/2021] [Indexed: 02/06/2023] Open
Abstract
A finite element analysis modelled diffusional generation of steady-state Ca2+ microdomains within skeletal muscle transverse (T)-tubular-sarcoplasmic reticular (SR) junctions, sites of ryanodine receptor (RyR)-mediated SR Ca2+ release. It used established quantifications of sarcomere and T-SR anatomy (radial diameter [Formula: see text]; axial distance [Formula: see text]). Its boundary SR Ca2+ influx densities,[Formula: see text], reflected step impositions of influxes, [Formula: see text] deduced from previously measured Ca2+ signals following muscle fibre depolarization. Predicted steady-state T-SR junctional edge [Ca2+], [Ca2+]edge, matched reported corresponding experimental cytosolic [Ca2+] elevations given diffusional boundary efflux [Formula: see text] established cytosolic Ca2+ diffusion coefficients [Formula: see text] and exit length [Formula: see text]. Dependences of predicted [Ca2+]edge upon [Formula: see text] then matched those of experimental [Ca2+] upon Ca2+ release through their entire test voltage range. The resulting model consistently predicted elevated steady-state T-SR junctional ~ µM-[Ca2+] elevations radially declining from maxima at the T-SR junction centre along the entire axial T-SR distance. These [Ca2+] heterogeneities persisted through 104- and fivefold, variations in D and w around, and fivefold reductions in d below, control values, and through reported resting muscle cytosolic [Ca2+] values, whilst preserving the flux conservation ([Formula: see text] condition, [Formula: see text]. Skeletal muscle thus potentially forms physiologically significant ~ µM-[Ca2+] T-SR microdomains that could regulate cytosolic and membrane signalling molecules including calmodulin and RyR, These findings directly fulfil recent experimental predictions invoking such Ca2+ microdomains in observed regulatory effects upon Na+ channel function, in a mechanism potentially occurring in similar restricted intracellular spaces in other cell types.
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Affiliation(s)
- Oliver J. Bardsley
- grid.5335.00000000121885934Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG UK
| | - Hugh R. Matthews
- grid.5335.00000000121885934Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG UK
| | - Christopher L.-H. Huang
- grid.5335.00000000121885934Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG UK ,grid.5335.00000000121885934Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
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23
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Winkler J, Mylle E, De Meyer A, Pavie B, Merchie J, Grones P, Van Damme D. Visualizing protein-protein interactions in plants by rapamycin-dependent delocalization. THE PLANT CELL 2021; 33:1101-1117. [PMID: 33793859 PMCID: PMC7612334 DOI: 10.1093/plcell/koab004] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 12/15/2020] [Indexed: 05/19/2023]
Abstract
Identifying protein-protein interactions (PPIs) is crucial for understanding biological processes. Many PPI tools are available, yet only some function within the context of a plant cell. Narrowing down even further, only a few tools allow complex multi-protein interactions to be visualized. Here, we present a conditional in vivo PPI tool for plant research that meets these criteria. Knocksideways in plants (KSP) is based on the ability of rapamycin to alter the localization of a bait protein and its interactors via the heterodimerization of FKBP and FRB domains. KSP is inherently free from many limitations of other PPI systems. This in vivo tool does not require spatial proximity of the bait and prey fluorophores and it is compatible with a broad range of fluorophores. KSP is also a conditional tool and therefore the visualization of the proteins in the absence of rapamycin acts as an internal control. We used KSP to confirm previously identified interactions in Nicotiana benthamiana leaf epidermal cells. Furthermore, the scripts that we generated allow the interactions to be quantified at high throughput. Finally, we demonstrate that KSP can easily be used to visualize complex multi-protein interactions. KSP is therefore a versatile tool with unique characteristics and applications that complements other plant PPI methods.
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Affiliation(s)
- Joanna Winkler
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Evelien Mylle
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Andreas De Meyer
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | | | - Julie Merchie
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Peter Grones
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
| | - Daniёl Van Damme
- Ghent University, Department of Plant Biotechnology and Bioinformatics, Technologiepark 71, 9052 Ghent, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052 Ghent, Belgium
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24
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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: 21] [Impact Index Per Article: 7.0] [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.
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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; , ,
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25
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Lin S, Meng T, Huang H, Zhuang H, He Z, Yang H, Feng D. Molecular machineries and physiological relevance of ER-mediated membrane contacts. Theranostics 2021; 11:974-995. [PMID: 33391516 PMCID: PMC7738843 DOI: 10.7150/thno.51871] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/22/2020] [Indexed: 02/06/2023] Open
Abstract
Membrane contact sites (MCSs) are defined as regions where two organelles are closely apposed, and most MCSs associated with each other via protein-protein or protein-lipid interactions. A number of key molecular machinery systems participate in mediating substance exchange and signal transduction, both of which are essential processes in terms of cellular physiology and pathophysiology. The endoplasmic reticulum (ER) is the largest reticulum network within the cell and has extensive communication with other cellular organelles, including the plasma membrane (PM), mitochondria, Golgi, endosomes and lipid droplets (LDs). The contacts and reactions between them are largely mediated by various protein tethers and lipids. Ions, lipids and even proteins can be transported between the ER and neighboring organelles or recruited to the contact site to exert their functions. This review focuses on the key molecules involved in the formation of different contact sites as well as their biological functions.
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26
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Zhemkov V, Liou J, Bezprozvanny I. Sigma 1 Receptor, Cholesterol and Endoplasmic Reticulum Contact Sites. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2021; 4:25152564211026505. [PMID: 37366370 PMCID: PMC10243589 DOI: 10.1177/25152564211026505] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/01/2021] [Accepted: 06/01/2021] [Indexed: 06/28/2023]
Abstract
Recent studies indicated potential importance of membrane contact sites (MCS) between the endoplasmic reticulum (ER) and other cellular organelles. These MCS have unique protein and lipid composition and serve as hubs for inter-organelle communication and signaling. Despite extensive investigation of MCS protein composition and functional roles, little is known about the process of MCS formation. In this perspective, we propose a hypothesis that MCS are formed not as a result of random interactions between membranes of ER and other organelles but on the basis of pre-existing cholesterol-enriched ER microdomains.
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Affiliation(s)
- Vladimir Zhemkov
- Department of Physiology,
UT Southwestern Medical Center at Dallas, Texas, United States
| | - Jen Liou
- Department of Physiology,
UT Southwestern Medical Center at Dallas, Texas, United States
| | - Ilya Bezprozvanny
- Department of Physiology,
UT Southwestern Medical Center at Dallas, Texas, United States
- Laboratory of Molecular
Neurodegeneration, Peter the Great St Petersburg State Polytechnic
University, Russia
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27
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Tiffner A, Derler I. Molecular Choreography and Structure of Ca 2+ Release-Activated Ca 2+ (CRAC) and K Ca2+ Channels and Their Relevance in Disease with Special Focus on Cancer. MEMBRANES 2020; 10:membranes10120425. [PMID: 33333945 PMCID: PMC7765462 DOI: 10.3390/membranes10120425] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/04/2020] [Accepted: 12/07/2020] [Indexed: 12/16/2022]
Abstract
Ca2+ ions play a variety of roles in the human body as well as within a single cell. Cellular Ca2+ signal transduction processes are governed by Ca2+ sensing and Ca2+ transporting proteins. In this review, we discuss the Ca2+ and the Ca2+-sensing ion channels with particular focus on the structure-function relationship of the Ca2+ release-activated Ca2+ (CRAC) ion channel, the Ca2+-activated K+ (KCa2+) ion channels, and their modulation via other cellular components. Moreover, we highlight their roles in healthy signaling processes as well as in disease with a special focus on cancer. As KCa2+ channels are activated via elevations of intracellular Ca2+ levels, we summarize the current knowledge on the action mechanisms of the interplay of CRAC and KCa2+ ion channels and their role in cancer cell development.
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28
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Zaman MF, Nenadic A, Radojičić A, Rosado A, Beh CT. Sticking With It: ER-PM Membrane Contact Sites as a Coordinating Nexus for Regulating Lipids and Proteins at the Cell Cortex. Front Cell Dev Biol 2020; 8:675. [PMID: 32793605 PMCID: PMC7387695 DOI: 10.3389/fcell.2020.00675] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 07/03/2020] [Indexed: 12/31/2022] Open
Abstract
Membrane contact sites between the cortical endoplasmic reticulum (ER) and the plasma membrane (PM) provide a direct conduit for small molecule transfer and signaling between the two largest membranes of the cell. Contact is established through ER integral membrane proteins that physically tether the two membranes together, though the general mechanism is remarkably non-specific given the diversity of different tethering proteins. Primary tethers including VAMP-associated proteins (VAPs), Anoctamin/TMEM16/Ist2p homologs, and extended synaptotagmins (E-Syts), are largely conserved in most eukaryotes and are both necessary and sufficient for establishing ER-PM association. In addition, other species-specific ER-PM tether proteins impart unique functional attributes to both membranes at the cell cortex. This review distils recent functional and structural findings about conserved and species-specific tethers that form ER-PM contact sites, with an emphasis on their roles in the coordinate regulation of lipid metabolism, cellular structure, and responses to membrane stress.
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Affiliation(s)
- Mohammad F Zaman
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Aleksa Nenadic
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada
| | - Ana Radojičić
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.,Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Abel Rosado
- Department of Botany, University of British Columbia, Vancouver, BC, Canada
| | - Christopher T Beh
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada.,The Centre for Cell Biology, Development, and Disease, Simon Fraser University, Burnaby, BC, Canada
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29
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Balla T, Kim YJ, Alvarez-Prats A, Pemberton J. Lipid Dynamics at Contact Sites Between the Endoplasmic Reticulum and Other Organelles. Annu Rev Cell Dev Biol 2020; 35:85-109. [PMID: 31590585 DOI: 10.1146/annurev-cellbio-100818-125251] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Phospholipids are synthesized primarily within the endoplasmic reticulum and are subsequently distributed to various subcellular membranes to maintain the unique lipid composition of specific organelles. As a result, in most cases, the steady-state localization of membrane phospholipids does not match their site of synthesis. This raises the question of how diverse lipid species reach their final membrane destinations and what molecular processes provide the energy to maintain the lipid gradients that exist between various membrane compartments. Recent studies have highlighted the role of inositol phospholipids in the nonvesicular transport of lipids at membrane contact sites. This review attempts to summarize our current understanding of these complex lipid dynamics and highlights their implications for defining future research directions.
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Affiliation(s)
- Tamas Balla
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Yeun Ju Kim
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Alejandro Alvarez-Prats
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA;
| | - Joshua Pemberton
- Section on Molecular Signal Transduction, Program for Developmental Neuroscience, Eunice Kennedy Shriver NICHD, National Institutes of Health, Bethesda, Maryland 20892, USA;
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30
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Collado J, Kalemanov M, Campelo F, Bourgoint C, Thomas F, Loewith R, Martínez-Sánchez A, Baumeister W, Stefan CJ, Fernández-Busnadiego R. Tricalbin-Mediated Contact Sites Control ER Curvature to Maintain Plasma Membrane Integrity. Dev Cell 2019; 51:476-487.e7. [PMID: 31743662 PMCID: PMC6863395 DOI: 10.1016/j.devcel.2019.10.018] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 09/23/2019] [Accepted: 10/16/2019] [Indexed: 12/23/2022]
Abstract
Membrane contact sites (MCS) between the endoplasmic reticulum (ER) and the plasma membrane (PM) play fundamental roles in all eukaryotic cells. ER-PM MCS are particularly abundant in Saccharomyces cerevisiae, where approximately half of the PM surface is covered by cortical ER (cER). Several proteins, including Ist2, Scs2/22, and Tcb1/2/3 are implicated in cER formation, but the specific roles of these molecules are poorly understood. Here, we use cryo-electron tomography to show that ER-PM tethers are key determinants of cER morphology. Notably, Tcb proteins (tricalbins) form peaks of extreme curvature on the cER membrane facing the PM. Combined modeling and functional assays suggest that Tcb-mediated cER peaks facilitate the transport of lipids between the cER and the PM, which is necessary to maintain PM integrity under heat stress. ER peaks were also present at other MCS, implying that membrane curvature enforcement may be a widespread mechanism to regulate MCS function.
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Affiliation(s)
- Javier Collado
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany; Institute of Neuropathology, University Medical Center Göttingen, Göttingen 37099, Germany; Graduate School of Quantitative Biosciences Munich, Munich 81337, Germany
| | - Maria Kalemanov
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany; Graduate School of Quantitative Biosciences Munich, Munich 81337, Germany
| | - Felix Campelo
- ICFO, Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, Castelldefels 08860, Spain
| | - Clélia Bourgoint
- Department of Molecular Biology, University of Geneva, Geneva 1211, Switzerland
| | - Ffion Thomas
- MRC Laboratory for Molecular Cell Biology, University College London, London, WC1E 6BT, UK
| | - Robbie Loewith
- Department of Molecular Biology, University of Geneva, Geneva 1211, Switzerland; Swiss National Centre for Competence in Research, Program Chemical Biology, Geneva 1211, Switzerland
| | - Antonio Martínez-Sánchez
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Wolfgang Baumeister
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany
| | - Christopher J Stefan
- MRC Laboratory for Molecular Cell Biology, University College London, London, WC1E 6BT, UK
| | - Rubén Fernández-Busnadiego
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, Martinsried 82152, Germany; Institute of Neuropathology, University Medical Center Göttingen, Göttingen 37099, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany.
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31
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Vierra NC, Kirmiz M, van der List D, Santana LF, Trimmer JS. Kv2.1 mediates spatial and functional coupling of L-type calcium channels and ryanodine receptors in mammalian neurons. eLife 2019; 8:49953. [PMID: 31663850 PMCID: PMC6839919 DOI: 10.7554/elife.49953] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/29/2019] [Indexed: 12/16/2022] Open
Abstract
The voltage-gated K+ channel Kv2.1 serves a major structural role in the soma and proximal dendrites of mammalian brain neurons, tethering the plasma membrane (PM) to endoplasmic reticulum (ER). Although Kv2.1 clustering at neuronal ER-PM junctions (EPJs) is tightly regulated and highly conserved, its function remains unclear. By identifying and evaluating proteins in close spatial proximity to Kv2.1-containing EPJs, we discovered that a significant role of Kv2.1 at EPJs is to promote the clustering and functional coupling of PM L-type Ca2+ channels (LTCCs) to ryanodine receptor (RyR) ER Ca2+ release channels. Kv2.1 clustering also unexpectedly enhanced LTCC opening at polarized membrane potentials. This enabled Kv2.1-LTCC-RyR triads to generate localized Ca2+ release events (i.e., Ca2+ sparks) independently of action potentials. Together, these findings uncover a novel mode of LTCC regulation and establish a unique mechanism whereby Kv2.1-associated EPJs provide a molecular platform for localized somatodendritic Ca2+ signals in mammalian brain neurons.
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Affiliation(s)
- Nicholas C Vierra
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, United States.,Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, United States
| | - Michael Kirmiz
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, United States
| | - Deborah van der List
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, United States.,Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, United States
| | - L Fernando Santana
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, United States
| | - James S Trimmer
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, United States.,Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, United States
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32
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Black DJ, Tran QK, Keightley A, Chinawalkar A, McMullin C, Persechini A. Evaluating Calmodulin-Protein Interactions by Rapid Photoactivated Cross-Linking in Live Cells Metabolically Labeled with Photo-Methionine. J Proteome Res 2019; 18:3780-3791. [PMID: 31483676 DOI: 10.1021/acs.jproteome.9b00510] [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] [Indexed: 01/08/2023]
Abstract
This work addresses the question of how the Ca2+ sensor protein calmodulin shapes cellular responses to Ca2+ signals. Proteins interacting with affinity tagged calmodulin were captured by rapid (t1/2 ≈ 7 s) photoactivated cross-linking under basal conditions, after brief removal of extracellular Ca2+ and during a cytosolic [Ca2+] transient in cells metabolically labeled with a photoreactive methionine analog. Tagged adducts were stringently enriched, and captured proteins were identified and quantified by LC-MS/MS. A set of 489 proteins including 27 known calmodulin interactors was derived. A threshold for fractional capture was applied to define a high specificity group of 170 proteins, including 22 known interactors, and a low specificity group of 319 proteins. Capture of ∼60% of the high specificity group was affected by manipulations of Ca2+, compared with ∼20% of the low specificity group. This suggests that the former is likely to contain novel interactors of physiological significance. The capture of 29 proteins, nearly all high specificity, was decreased by the removal of extracellular Ca2+, although this does not affect cytosolic [Ca2+]. Capture of half of these was unaffected by the cytosolic [Ca2+] transient, consistent with high local [Ca2+]. These proteins are hypothesized to reside in or near microdomains of high [Ca2+] supported by the Ca2+ influx.
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Affiliation(s)
- D J Black
- Division of Molecular Biology and Biochemistry , University of Missouri-Kansas City , Kansas City , Missouri 64110-2499 , United States
| | | | - Andrew Keightley
- Division of Molecular Biology and Biochemistry , University of Missouri-Kansas City , Kansas City , Missouri 64110-2499 , United States
| | - Ameya Chinawalkar
- Division of Molecular Biology and Biochemistry , University of Missouri-Kansas City , Kansas City , Missouri 64110-2499 , United States
| | - Cole McMullin
- Division of Molecular Biology and Biochemistry , University of Missouri-Kansas City , Kansas City , Missouri 64110-2499 , United States
| | - Anthony Persechini
- Division of Molecular Biology and Biochemistry , University of Missouri-Kansas City , 5007 Rockhill Road , Kansas City , Missouri 64110-2499 , United States
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33
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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: 4.6] [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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34
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Rimessi A, Pedriali G, Vezzani B, Tarocco A, Marchi S, Wieckowski MR, Giorgi C, Pinton P. Interorganellar calcium signaling in the regulation of cell metabolism: A cancer perspective. Semin Cell Dev Biol 2019; 98:167-180. [PMID: 31108186 DOI: 10.1016/j.semcdb.2019.05.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 05/13/2019] [Accepted: 05/14/2019] [Indexed: 01/22/2023]
Abstract
Organelles were originally considered to be individual cellular compartments with a defined organization and function. However, recent studies revealed that organelles deeply communicate within each other via Ca2+ exchange. This communication, mediated by specialized membrane regions in close apposition between two organelles, regulate cellular functions, including metabolism and cell fate decisions. Advances in microscopy techniques, molecular biology and biochemistry have increased our understanding of these interorganelle platforms. Research findings suggest that interorganellar Ca2+ signaling, which is altered in cancer, influences tumorigenesis and tumor progression by controlling cell death programs and metabolism. Here, we summarize the available data on the existence and composition of interorganelle platforms connecting the endoplasmic reticulum with mitochondria, the plasma membrane, or endolysosomes. Finally, we provide a timely overview of the potential function of interorganellar Ca2+ signaling in maintaining cellular homeostasis.
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Affiliation(s)
- Alessandro Rimessi
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology and Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy.
| | - Gaia Pedriali
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology and Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy
| | - Bianca Vezzani
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology and Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy
| | - Anna Tarocco
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology and Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy; Neonatal Intensive Care Unit, University Hospital S. Anna Ferrara, 44124 Ferrara, Italy
| | - Saverio Marchi
- Dept. of Clinical and Molecular Sciences, Polytechnical University of Marche, 60126 Ancona, Italy
| | | | - Carlotta Giorgi
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology and Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy
| | - Paolo Pinton
- Dept. of Morphology, Surgery and Experimental Medicine, Section of Pathology, Oncology and Experimental Biology and Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy; Maria Cecilia Hospital, GVM Care & Research, 48033 Cotignola, Ravenna, Italy.
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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: 19] [Impact Index Per Article: 3.8] [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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Analysis of Phosphatidylinositol Transfer at ER-PM Junctions in Receptor-Stimulated Live Cells. Methods Mol Biol 2019. [PMID: 30790244 DOI: 10.1007/978-1-4939-9136-5_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Phosphatidylinositol (PI) is an inositol-containing phospholipid synthesized in the endoplasmic reticulum (ER). PI is a precursor lipid for PI 4,5-bisphosphate (PI(4,5)P2) in the plasma membrane (PM) important for Ca2+ signaling in response to extracellular stimuli. Thus, ER-to-PM PI transfer becomes essential for cells to maintain PI(4,5)P2 homeostasis during receptor stimulation. In this chapter, we discuss two live-cell imaging protocols to analyze ER-to-PM PI transfer at ER-PM junctions, where the two membrane compartments make close appositions accommodating PI transfer. First, we describe how to monitor PI(4,5)P2 replenishment following receptor stimulation, as a readout of PI transfer, using a PI(4,5)P2 biosensor and total internal reflection fluorescence microscopy. The second protocol directly visualizes PI transfer proteins that accumulate at ER-PM junctions and mediate PI(4,5)P2 replenishment with PI in the ER in stimulated cells. These methods provide spatial and temporal analysis of ER-to-PM PI transfer during receptor stimulation and can be adapted to other research questions related to this topic.
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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: 35] [Impact Index Per Article: 7.0] [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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Michaud M, Jouhet J. Lipid Trafficking at Membrane Contact Sites During Plant Development and Stress Response. FRONTIERS IN PLANT SCIENCE 2019; 10:2. [PMID: 30713540 PMCID: PMC6346683 DOI: 10.3389/fpls.2019.00002] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 01/03/2019] [Indexed: 05/20/2023]
Abstract
The biogenesis of cellular membranes involves an important traffic of lipids from their site of synthesis to their final destination. Lipid transfer can be mediated by vesicular or non-vesicular pathways. The non-vesicular pathway requires the close apposition of two membranes to form a functional platform, called membrane contact sites (MCSs), where lipids are exchanged. These last decades, MCSs have been observed between virtually all organelles and a role in lipid transfer has been demonstrated for some of them. In plants, the lipid composition of membranes is highly dynamic and can be drastically modified in response to environmental changes. This highlights the importance of understanding the mechanisms involved in the regulation of membrane lipid homeostasis in plants. This review summarizes our current knowledge about the non-vesicular transport of lipids at MCSs in plants and its regulation during stress.
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Host cellular unfolded protein response signaling regulates Campylobacter jejuni invasion. PLoS One 2018; 13:e0205865. [PMID: 30321237 PMCID: PMC6188877 DOI: 10.1371/journal.pone.0205865] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 10/02/2018] [Indexed: 12/20/2022] Open
Abstract
Campylobacter jejuni is a major cause of bacterial foodborne illness in humans worldwide. Bacterial entry into a host eukaryotic cell involves the initial steps of adherence and invasion, which generally activate several cell-signaling pathways that induce the activation of innate defense systems, which leads to the release of proinflammatory cytokines and induction of apoptosis. Recent studies have reported that the unfolded protein response (UPR), a system to clear unfolded proteins from the endoplasmic reticulum (ER), also participates in the activation of cellular defense mechanisms in response to bacterial infection. However, no study has yet investigated the role of UPR in C. jejuni infection. Hence, the aim of this study was to deduce the role of UPR signaling via induction of ER stress in the process of C. jejuni infection. The results suggest that C. jejuni infection suppresses global protein translation. Also, 12 h of C. jejuni infection induced activation of the eIF2α pathway and expression of the transcription factor CHOP. Interestingly, bacterial invasion was facilitated by knockdown of UPR-associated signaling factors and treatment with the ER stress inducers, thapsigargin and tunicamycin, decreased the invasive ability of C. jejuni. An investigation into the mechanism of UPR-mediated inhibition of C. jejuni invasion showed that UPR signaling did not affect bacterial adhesion to or survival in the host cells. Further, Salmonella Enteritidis or FITC-dextran intake were not regulated by UPR signaling. These results indicated that the effect of UPR on intracellular intake was specifically found in C. jejuni infection. These findings are the first to describe the role of UPR in C. jejuni infection and revealed the participation of a new signaling pathway in C. jejuni invasion. UPR signaling is involved in defense against the early step of C. jejuni invasion and thus presents a potential therapeutic target for the treatment of C. jejuni infection.
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Heterocyclic sterol probes for live monitoring of sterol trafficking and lysosomal storage disorders. Sci Rep 2018; 8:14428. [PMID: 30258093 PMCID: PMC6158244 DOI: 10.1038/s41598-018-32776-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 09/14/2018] [Indexed: 12/13/2022] Open
Abstract
The monitoring of intracellular cholesterol homeostasis and trafficking is of great importance because their imbalance leads to many pathologies. Reliable tools for cholesterol detection are in demand. This study presents the design and synthesis of fluorescent probes for cholesterol recognition and demonstrates their selectivity by a variety of methods. The construction of dedicated library of 14 probes was based on heterocyclic (pyridine)-sterol derivatives with various attached fluorophores. The most promising probe, a P1-BODIPY conjugate FP-5, was analysed in detail and showed an intensive labelling of cellular membranes followed by intracellular redistribution into various cholesterol rich organelles and vesicles. FP-5 displayed a stronger signal, with faster kinetics, than the commercial TF-Chol probe. In addition, cells with pharmacologically disrupted cholesterol transport, or with a genetic mutation of cholesterol transporting protein NPC1, exhibited strong and fast FP-5 signal in the endo/lysosomal compartment, co-localizing with filipin staining of cholesterol. Hence, FP-5 has high potential as a new probe for monitoring cholesterol trafficking and its disorders.
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41
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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: 41] [Impact Index Per Article: 6.8] [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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Courjaret R, Dib M, Machaca K. Spatially restricted subcellular Ca 2+ signaling downstream of store-operated calcium entry encoded by a cortical tunneling mechanism. Sci Rep 2018; 8:11214. [PMID: 30046136 PMCID: PMC6060099 DOI: 10.1038/s41598-018-29562-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/10/2018] [Indexed: 11/10/2022] Open
Abstract
Agonist-dependent Ca2+ mobilization results in Ca2+ store depletion and Store-Operated Calcium Entry (SOCE), which is spatially restricted to microdomains defined by cortical ER – plasma membrane contact sites (MCS). However, some Ca2+-dependent effectors that localize away from SOCE microdomains, are activated downstream of SOCE by mechanisms that remain obscure. One mechanism proposed initially in acinar cells and termed Ca2+ tunneling, mediates the uptake of Ca2+ flowing through SOCE into the ER followed by release at distal sites through IP3 receptors. Here we show that Ca2+ tunneling encodes exquisite specificity downstream of SOCE signal by dissecting the sensitivity and dependence of multiple effectors in HeLa cells. While mitochondria readily perceive Ca2+ release when stores are full, SOCE shows little effect in raising mitochondrial Ca2+, and Ca2+-tunneling is completely inefficient. In contrast, gKCa displays a similar sensitivity to Ca2+ release and tunneling, while the activation of NFAT1 is selectively responsive to SOCE and not to Ca2+ release. These results show that in contrast to the previously described long-range Ca2+ tunneling, in non-specialized HeLa cells this mechanism mediates spatially restricted Ca2+ rise within the cortical region of the cell to activate a specific subset of effectors.
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Affiliation(s)
- Raphael Courjaret
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City - Qatar Foundation, Doha, Qatar
| | - Maya Dib
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City - Qatar Foundation, Doha, Qatar
| | - Khaled Machaca
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City - Qatar Foundation, Doha, Qatar.
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Cabukusta B, Neefjes J. Mechanisms of lysosomal positioning and movement. Traffic 2018; 19:761-769. [PMID: 29900632 PMCID: PMC6175085 DOI: 10.1111/tra.12587] [Citation(s) in RCA: 148] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2018] [Revised: 06/07/2018] [Accepted: 06/11/2018] [Indexed: 12/12/2022]
Abstract
Lysosomes are highly dynamic organelles that can move rapidly throughout the cell. They distribute in a rather immobile pool located around the microtubule‐organizing center in a “cloud,” and a highly dynamic pool in the cell periphery. Their spatiotemporal characteristics allow them to carry out multiple biological functions, such as cargo degradation, antigen presentation and plasma membrane repair. Therefore, it is not surprising that lysosomal dysfunction underlies various diseases, including cancer, neurodegenerative and autoimmune diseases. In most of these biological events, the involvement of lysosomes is dependent on their ability to move throughout the cytoplasm, to find and fuse to the correct compartments to receive and deliver substrates for further handling. These dynamics are orchestrated by motor proteins moving along cytoskeletal components. The complexity of the mechanisms responsible for controlling lysosomal transport has recently been appreciated and has yielded novel insights into interorganellar communication, as well as lipid‐protein interplay. In this review, we discuss the current understanding of the mechanisms of lysosomal transport and the molecular machineries that control this mobility.
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Affiliation(s)
- Birol Cabukusta
- Department of Cell and Chemical Biology, Oncode Institute, Leiden University Medical Center, Leiden, The Netherlands
| | - Jacques Neefjes
- Department of Cell and Chemical Biology, Oncode Institute, Leiden University Medical Center, Leiden, The Netherlands
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44
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Identification of VAPA and VAPB as Kv2 Channel-Interacting Proteins Defining Endoplasmic Reticulum-Plasma Membrane Junctions in Mammalian Brain Neurons. J Neurosci 2018; 38:7562-7584. [PMID: 30012696 DOI: 10.1523/jneurosci.0893-18.2018] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Revised: 06/01/2018] [Accepted: 07/07/2018] [Indexed: 11/21/2022] Open
Abstract
Membrane contacts between endoplasmic reticulum (ER) and plasma membrane (PM), or ER-PM junctions, are ubiquitous in eukaryotic cells and are platforms for lipid and calcium signaling and homeostasis. Recent studies have revealed proteins crucial to the formation and function of ER-PM junctions in non-neuronal cells, but little is known of the ER-PM junctions prominent in aspiny regions of mammalian brain neurons. The Kv2.1 voltage-gated potassium channel is abundantly clustered at ER-PM junctions in brain neurons and is the first PM protein that functions to organize ER-PM junctions. However, the molecular mechanism whereby Kv2.1 localizes to and remodels these junctions is unknown. We used affinity immunopurification and mass spectrometry-based proteomics on brain samples from male and female WT and Kv2.1 KO mice and identified the resident ER vesicle-associated membrane protein-associated proteins isoforms A and B (VAPA and VAPB) as prominent Kv2.1-associated proteins. Coexpression with Kv2.1 or its paralog Kv2.2 was sufficient to recruit VAPs to ER-PM junctions. Multiplex immunolabeling revealed colocalization of Kv2.1 and Kv2.2 with endogenous VAPs at ER-PM junctions in brain neurons from male and female mice in situ and in cultured rat hippocampal neurons, and KO of VAPA in mammalian cells reduces Kv2.1 clustering. The association of VAPA with Kv2.1 relies on a "two phenylalanines in an acidic tract" (FFAT) binding domain on VAPA and a noncanonical phosphorylation-dependent FFAT motif comprising the Kv2-specific clustering or PRC motif. These results suggest that Kv2.1 localizes to and organizes neuronal ER-PM junctions through an interaction with VAPs.SIGNIFICANCE STATEMENT Our study identified the endoplasmic reticulum (ER) proteins vesicle-associated membrane protein-associated proteins isoforms A and B (VAPA and VAPB) as proteins copurifying with the plasma membrane (PM) Kv2.1 ion channel. We found that expression of Kv2.1 recruits VAPs to ER-PM junctions, specialized membrane contact sites crucial to distinct aspects of cell function. We found endogenous VAPs at Kv2.1-mediated ER-PM junctions in brain neurons and other mammalian cells and that knocking out VAPA expression disrupts Kv2.1 clustering. We identified domains of VAPs and Kv2.1 necessary and sufficient for their association at ER-PM junctions. Our study suggests that Kv2.1 expression in the PM can affect ER-PM junctions via its phosphorylation-dependent association to ER-localized VAPA and VAPB.
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45
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Cohen S, Valm AM, Lippincott-Schwartz J. Interacting organelles. Curr Opin Cell Biol 2018; 53:84-91. [PMID: 30006038 DOI: 10.1016/j.ceb.2018.06.003] [Citation(s) in RCA: 144] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 06/06/2018] [Accepted: 06/12/2018] [Indexed: 12/11/2022]
Abstract
Eukaryotic cells are organized into membrane-bound organelles. These organelles communicate with one another through vesicular trafficking pathways and membrane contact sites (MCSs). MCSs are sites of close apposition between two or more organelles that play diverse roles in the exchange of metabolites, lipids and proteins. Organelle interactions at MCSs also are important for organelle division and biogenesis. For example, the division of several organelles, including mitochondria and endosomes, seem to be regulated by contacts with the endoplasmic reticulum (ER). Moreover, the biogenesis of autophagosomes and peroxisomes involves contributions from the ER and multiple other cellular compartments. Thus, organelle-organelle interactions allow cells to alter the shape and activities of their membrane-bound compartments, allowing them to cope with different developmental and environmental conditions.
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Affiliation(s)
- Sarah Cohen
- University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Alex M Valm
- University at Albany, SUNY, Albany, NY, United States
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46
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Shih YT, Hsueh YP. The involvement of endoplasmic reticulum formation and protein synthesis efficiency in VCP- and ATL1-related neurological disorders. J Biomed Sci 2018; 25:2. [PMID: 29310658 PMCID: PMC5757295 DOI: 10.1186/s12929-017-0403-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Accepted: 12/26/2017] [Indexed: 12/13/2022] Open
Abstract
The endoplasmic reticulum (ER) is the biggest organelle in cells and is involved in versatile cellular processes. Formation and maintenance of ER morphology are regulated by a series of proteins controlling membrane fusion and curvature. At least six different ER morphology regulators have been demonstrated to be involved in neurological disorders-including Valosin-containing protein (VCP), Atlastin-1 (ATL1), Spastin (SPAST), Reticulon 2 (RTN2), Receptor expression enhancing protein 1 (REEP1) and RAB10-suggesting a critical role of ER formation in neuronal activity and function. Among these genes, mutations in VCP gene involve in inclusion body myopathy with Paget disease of bone and frontotemporal dementia (IBMPFD), familial amyotrophic lateral sclerosis (ALS), autism spectrum disorders (ASD), and hereditary spastic paraplegia (HSP). ATL1 is also one of causative genes of HSP. RAB10 is associated with Parkinson's disease (PD). A recent study showed that VCP and ATL1 work together to regulate dendritic spine formation by controlling ER formation and consequent protein synthesis efficiency. RAB10 shares the same function with VCP and ATL1 to control ER formation and protein synthesis efficiency but acts independently. Increased protein synthesis by adding extra leucine to cultured neurons ameliorated dendritic spine deficits caused by VCP and ATL1 deficiencies, strengthening the significance of protein synthesis in VCP- and ATL1-regulated dendritic spine formation. These findings provide new insight into the roles of ER and protein synthesis in controlling dendritic spine formation and suggest a potential etiology of neurodegenerative disorders caused by mutations in VCP, ATL1 and other genes encoding proteins regulating ER formation and morphogenesis.
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Affiliation(s)
- Yu-Tzu Shih
- Institute of Molecular Biology, Academia Sinica, 128, Academia Rd., Sec. 2, Taipei, 11529, Taiwan
| | - Yi-Ping Hsueh
- Institute of Molecular Biology, Academia Sinica, 128, Academia Rd., Sec. 2, Taipei, 11529, Taiwan.
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47
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Hsieh TS, Chen YJ, Chang CL, Lee WR, Liou J. Cortical actin contributes to spatial organization of ER-PM junctions. Mol Biol Cell 2017; 28:3171-3180. [PMID: 28954864 PMCID: PMC5687020 DOI: 10.1091/mbc.e17-06-0377] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 09/18/2017] [Accepted: 09/20/2017] [Indexed: 01/16/2023] Open
Abstract
Endoplasmic reticulum-plasma membrane (ER-PM) junctions mediate crucial activities ranging from Ca2+ signaling to lipid metabolism. Spatial organization of ER-PM junctions may modulate the extent and location of these cellular activities. However, the morphology and distribution of ER-PM junctions are not well characterized. Using photoactivated localization microscopy, we reveal that the contact area of single ER-PM junctions is mainly oblong with the dimensions of ∼120 nm × ∼80 nm in HeLa cells. Using total internal reflection fluorescence microscopy and structure illumination microscopy, we show that cortical actin contributes to spatial distribution and stability of ER-PM junctions. Further functional assays suggest that intact F-actin architecture is required for phosphatidylinositol 4,5-bisphosphate homeostasis mediated by Nir2 at ER-PM junctions. Together, our study provides quantitative information on spatial organization of ER-PM junctions that is in part regulated by F-actin. We envision that functions of ER-PM junctions can be differentially regulated through dynamic actin remodeling during cellular processes.
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Affiliation(s)
- Ting-Sung Hsieh
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Yu-Ju Chen
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Chi-Lun Chang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Wan-Ru Lee
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Jen Liou
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390
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48
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Subedi KP, Ong HL, Ambudkar IS. Assembly of ER-PM Junctions: A Critical Determinant in the Regulation of SOCE and TRPC1. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 981:253-276. [PMID: 29594865 DOI: 10.1007/978-3-319-55858-5_11] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Store-operated calcium entry (SOCE), a unique plasma membrane Ca2+ entry mechanism, is activated when ER-[Ca2+] is decreased. SOCE is mediated via the primary channel, Orai1, as well as others such as TRPC1. STIM1 and STIM2 are ER-Ca2+ sensor proteins that regulate Orai1 and TRPC1. SOCE requires assembly of STIM proteins with the plasma membrane channels which occurs within distinct regions in the cell that have been termed as endoplasmic reticulum (ER)-plasma membrane (PM) junctions. The PM and ER are in close proximity to each other within this region, which allows STIM1 in the ER to interact with and activate either Orai1 or TRPC1 in the plasma membrane. Activation and regulation of SOCE involves dynamic assembly of various components that are involved in mediating Ca2+ entry as well as those that determine the formation and stabilization of the junctions. These components include proteins in the cytosol, ER and PM, as well as lipids in the PM. Recent studies have also suggested that SOCE and its components are compartmentalized within ER-PM junctions and that this process might require remodeling of the plasma membrane lipids and reorganization of structural and scaffolding proteins. Such compartmentalization leads to the generation of spatially- and temporally-controlled Ca2+signals that are critical for regulating many downstream cellular functions.
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Affiliation(s)
- Krishna P Subedi
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Hwei Ling Ong
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA
| | - Indu S Ambudkar
- Secretory Physiology Section, Molecular Physiology and Therapeutics Branch, NIDCR, NIH, Bethesda, MD, USA.
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