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Wang Y, Song L, Guo C, Ji R. Proteomic Identification and Characterization of Collagen from Bactrian Camel ( Camelus bactrianus) Hoof. Foods 2023; 12:3303. [PMID: 37685234 PMCID: PMC10486769 DOI: 10.3390/foods12173303] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/26/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
With the development of camel-derived food and pharmaceutical cosmetics, camel hoof, as a unique by-product of the camel industry, has gradually attracted the attention of scientific researchers in the fields of nutrition, health care, and biomaterial development. In this study, the protein composition and collagen type of Bactrian camel hoof collagen extract (CHC) were analyzed by LC-MS/MS, and the functional properties of CHC were further investigated, including its rheological characteristics, emulsification and emulsion stability, and hygroscopicity and humectancy. Proteomic identification confirmed that CHC had 13 collagen subunits, dominated by type I collagen (α1, α2), with molecular weights mainly in the 100-200 KDa range and a pI of 7.48. An amino acid study of CHC revealed that it carried the standard amino acid profile of type I collagen and was abundant in Gly, Pro, Glu, Ala, and Arg. Additionally, studies using circular dichroism spectroscopy and Fourier transform infrared spectroscopy revealed that CHC contains a collagen-like triple helix structure that is stable and intact. Different concentrations of CHC solutions showed shear-thinning flow behavior. Its tan δ did not differ much with increasing concentration. The CHC has good emulsifying ability and stability, humectancy, and hygroscopicity. This study provides a basis for utilizing and developing Bactrian camel hoof collagen as a functional ingredient.
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Affiliation(s)
- Yingli Wang
- College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China; (Y.W.); (L.S.); (C.G.)
| | - Le Song
- College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China; (Y.W.); (L.S.); (C.G.)
| | - Chengcheng Guo
- College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China; (Y.W.); (L.S.); (C.G.)
| | - Rimutu Ji
- College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, China; (Y.W.); (L.S.); (C.G.)
- Inner Mongolia Institute of Camel Research, Alxa 737300, China
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2
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Overduin M, Tran A, Eekels DM, Overduin F, Kervin TA. Transmembrane Membrane Readers form a Novel Class of Proteins That Include Peripheral Phosphoinositide Recognition Domains and Viral Spikes. MEMBRANES 2022; 12:1161. [PMID: 36422153 PMCID: PMC9692390 DOI: 10.3390/membranes12111161] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 11/11/2022] [Accepted: 11/15/2022] [Indexed: 06/16/2023]
Abstract
Membrane proteins are broadly classified as transmembrane (TM) or peripheral, with functions that pertain to only a single bilayer at a given time. Here, we explicate a class of proteins that contain both transmembrane and peripheral domains, which we dub transmembrane membrane readers (TMMRs). Their transmembrane and peripheral elements anchor them to one bilayer and reversibly attach them to another section of bilayer, respectively, positioning them to tether and fuse membranes while recognizing signals such as phosphoinositides (PIs) and modifying lipid chemistries in proximity to their transmembrane domains. Here, we analyze full-length models from AlphaFold2 and Rosetta, as well as structures from nuclear magnetic resonance (NMR) spectroscopy and X-ray crystallography, using the Membrane Optimal Docking Area (MODA) program to map their membrane-binding surfaces. Eukaryotic TMMRs include phospholipid-binding C1, C2, CRAL-TRIO, FYVE, GRAM, GTPase, MATH, PDZ, PH, PX, SMP, StART and WD domains within proteins including protrudin, sorting nexins and synaptotagmins. The spike proteins of SARS-CoV-2 as well as other viruses are also TMMRs, seeing as they are anchored into the viral membrane while mediating fusion with host cell membranes. As such, TMMRs have key roles in cell biology and membrane trafficking, and include drug targets for diseases such as COVID-19.
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Affiliation(s)
- Michael Overduin
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Anh Tran
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | | | - Finn Overduin
- Institute of Nutritional Science, University of Potsdam, 14476 Potsdam, Germany
| | - Troy A. Kervin
- Department of Biochemistry, University of Alberta, Edmonton, AB T6G 2H7, Canada
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3
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STIM Proteins and Regulation of SOCE in ER-PM Junctions. Biomolecules 2022; 12:biom12081152. [PMID: 36009047 PMCID: PMC9405863 DOI: 10.3390/biom12081152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/12/2022] [Accepted: 08/15/2022] [Indexed: 11/30/2022] Open
Abstract
ER-PM junctions are membrane contact sites formed by the endoplasmic reticulum (ER) and plasma membrane (PM) in close apposition together. The formation and stability of these junctions are dependent on constitutive and dynamic enrichment of proteins, which either contribute to junctional stability or modulate the lipid levels of both ER and plasma membranes. The ER-PM junctions have come under much scrutiny recently as they serve as hubs for assembling the Ca2+ signaling complexes. This review summarizes: (1) key findings that underlie the abilities of STIM proteins to accumulate in ER-PM junctions; (2) the modulation of Orai/STIM complexes by other components found within the same junction; and (3) how Orai1 channel activation is coordinated and coupled with downstream signaling pathways.
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4
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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: 3] [Impact Index Per Article: 1.5] [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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5
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Jean S, Nassari S. Regulation of Endosomal Sorting and Maturation by ER-Endosome Contact Sites. CONTACT (THOUSAND OAKS (VENTURA COUNTY, CALIF.)) 2022; 5:25152564221106046. [PMID: 37366507 PMCID: PMC10243584 DOI: 10.1177/25152564221106046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
Endosomes are a heterogeneous population of intracellular organelles responsible for sorting, recycling, or transporting internalized materials for degradation. Endosomal sorting and maturation are controlled by a complex interplay of regulators, with RAB GTPases and phosphoinositides playing key roles. In this decade, another layer of regulation surfaced with the role played by membrane contact sites between the endoplasmic reticulum (ER) and endosomes. Specific regulators of ER-endosome contact sites or proteins localized at these sites are emerging as modulators of this complex endosomal ballet. In particular, lipid transfer or recruitment of various complexes and enzymes at ER-endosome contact sites play an active role in endosome sorting, scission, and maturation. In this short review, we focus on studies describing ER-endosome contact sites in these three endosomal processes.
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Affiliation(s)
- Steve Jean
- Faculté de médecine et des sciences de la santé,
Département d’immunologie et de biologie cellulaire, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Sonya Nassari
- Faculté de médecine et des sciences de la santé,
Département d’immunologie et de biologie cellulaire, Université de Sherbrooke, Sherbrooke, Québec, Canada
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6
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Lenoir G, D'Ambrosio JM, Dieudonné T, Čopič A. Transport Pathways That Contribute to the Cellular Distribution of Phosphatidylserine. Front Cell Dev Biol 2021; 9:737907. [PMID: 34540851 PMCID: PMC8440936 DOI: 10.3389/fcell.2021.737907] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 08/10/2021] [Indexed: 12/05/2022] Open
Abstract
Phosphatidylserine (PS) is a negatively charged phospholipid that displays a highly uneven distribution within cellular membranes, essential for establishment of cell polarity and other processes. In this review, we discuss how combined action of PS biosynthesis enzymes in the endoplasmic reticulum (ER), lipid transfer proteins (LTPs) acting within membrane contact sites (MCS) between the ER and other compartments, and lipid flippases and scramblases that mediate PS flip-flop between membrane leaflets controls the cellular distribution of PS. Enrichment of PS in specific compartments, in particular in the cytosolic leaflet of the plasma membrane (PM), requires input of energy, which can be supplied in the form of ATP or by phosphoinositides. Conversely, coupling between PS synthesis or degradation, PS flip-flop and PS transfer may enable PS transfer by passive flow. Such scenario is best documented by recent work on the formation of autophagosomes. The existence of lateral PS nanodomains, which is well-documented in the case of the PM and postulated for other compartments, can change the steepness or direction of PS gradients between compartments. Improvements in cellular imaging of lipids and membranes, lipidomic analysis of complex cellular samples, reconstitution of cellular lipid transport reactions and high-resolution structural data have greatly increased our understanding of cellular PS homeostasis. Our review also highlights how budding yeast has been instrumental for our understanding of the organization and transport of PS in cells.
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Affiliation(s)
- Guillaume Lenoir
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell, Gif-sur-Yvette, France
| | - Juan Martín D'Ambrosio
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, Montpellier, France
| | - Thibaud Dieudonné
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic EMBL Partnership for Molecular Medicine, Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Alenka Čopič
- Centre de Recherche en Biologie Cellulaire de Montpellier (CRBM), Université de Montpellier, CNRS, Montpellier, France
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7
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Jamecna D, Antonny B. Intrinsically disordered protein regions at membrane contact sites. Biochim Biophys Acta Mol Cell Biol Lipids 2021; 1866:159020. [PMID: 34352388 DOI: 10.1016/j.bbalip.2021.159020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 06/30/2021] [Accepted: 07/01/2021] [Indexed: 12/14/2022]
Abstract
Membrane contact sites (MCS) are regions of close apposition between membrane-bound organelles. Proteins that occupy MCS display various domain organisation. Among them, lipid transfer proteins (LTPs) frequently contain both structured domains as well as regions of intrinsic disorder. In this review, we discuss the various roles of intrinsically disordered protein regions (IDPRs) in LTPs as well as in other proteins that are associated with organelle contact sites. We distinguish the following functions: (i) to act as flexible tethers between two membranes; (ii) to act as entropic barriers to prevent protein crowding and regulate membrane tethering geometry; (iii) to define the action range of catalytic domains. These functions are added to other functions of IDPRs in membrane environments, such as mediating protein-protein and protein-membrane interactions. We suggest that the overall efficiency and fidelity of contact sites might require fine coordination between all these IDPR activities.
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Affiliation(s)
- Denisa Jamecna
- Université Côte d'Azur et CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France; Biochemistry Center (BZH), Heidelberg, Germany
| | - Bruno Antonny
- Université Côte d'Azur et CNRS, Institut de Pharmacologie Moléculaire et Cellulaire, 660 route des lucioles, 06560 Valbonne, France.
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8
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Qian T, Li C, He R, Wan C, Liu Y, Yu H. Calcium-dependent and -independent lipid transfer mediated by tricalbins in yeast. J Biol Chem 2021; 296:100729. [PMID: 33933446 PMCID: PMC8163979 DOI: 10.1016/j.jbc.2021.100729] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Revised: 04/23/2021] [Accepted: 04/28/2021] [Indexed: 11/12/2022] Open
Abstract
Membrane contact sites (MCSs) formed between the endoplasmic reticulum (ER) and the plasma membrane (PM) provide a platform for nonvesicular lipid exchange. The ER-anchored tricalbins (Tcb1, Tcb2, and Tcb3) are critical tethering factors at ER–PM MCSs in yeast. Tricalbins possess a synaptotagmin-like mitochondrial-lipid-binding protein (SMP) domain and multiple Ca2+-binding C2 domains. Although tricalbins have been suggested to be involved in lipid exchange at the ER–PM MCSs, it remains unclear whether they directly mediate lipid transport. Here, using in vitro lipid transfer assays, we discovered that tricalbins are capable of transferring phospholipids between membranes. Unexpectedly, while its lipid transfer activity was markedly elevated by Ca2+, Tcb3 constitutively transferred lipids even in the absence of Ca2+. The stimulatory activity of Ca2+ on Tcb3 required intact Ca2+-binding sites on both the C2C and C2D domains of Tcb3, while Ca2+-independent lipid transport was mediated by the SMP domain that transferred lipids via direct interactions with phosphatidylserine and other negatively charged lipid molecules. These findings establish tricalbins as lipid transfer proteins, and reveal Ca2+-dependent and -independent lipid transfer activities mediated by these tricalbins, providing new insights into their mechanism in maintaining PM integrity at ER–PM MCSs.
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Affiliation(s)
- Tiantian Qian
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Chenlu Li
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Ruyue He
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Chun Wan
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado, USA
| | - Yinghui Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China.
| | - Haijia Yu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China.
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9
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Crul T, Maléth J. Endoplasmic Reticulum-Plasma Membrane Contact Sites as an Organizing Principle for Compartmentalized Calcium and cAMP Signaling. Int J Mol Sci 2021; 22:4703. [PMID: 33946838 PMCID: PMC8124356 DOI: 10.3390/ijms22094703] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 04/20/2021] [Accepted: 04/27/2021] [Indexed: 01/14/2023] Open
Abstract
In eukaryotic cells, ultimate specificity in activation and action-for example, by means of second messengers-of the myriad of signaling cascades is primordial. In fact, versatile and ubiquitous second messengers, such as calcium (Ca2+) and cyclic adenosine monophosphate (cAMP), regulate multiple-sometimes opposite-cellular functions in a specific spatiotemporal manner. Cells achieve this through segregation of the initiators and modulators to specific plasma membrane (PM) subdomains, such as lipid rafts and caveolae, as well as by dynamic close contacts between the endoplasmic reticulum (ER) membrane and other intracellular organelles, including the PM. Especially, these membrane contact sites (MCSs) are currently receiving a lot of attention as their large influence on cell signaling regulation and cell physiology is increasingly appreciated. Depletion of ER Ca2+ stores activates ER membrane STIM proteins, which activate PM-residing Orai and TRPC Ca2+ channels at ER-PM contact sites. Within the MCS, Ca2+ fluxes relay to cAMP signaling through highly interconnected networks. However, the precise mechanisms of MCS formation and the influence of their dynamic lipid environment on their functional maintenance are not completely understood. The current review aims to provide an overview of our current understanding and to identify open questions of the field.
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Affiliation(s)
- Tim Crul
- First Department of Medicine, University of Szeged, H6720 Szeged, Hungary
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, University of Szeged, H6720 Szeged, Hungary
- HCEMM-SZTE Molecular Gastroenterology Research Group, University of Szeged, H6720 Szeged, Hungary
| | - József Maléth
- First Department of Medicine, University of Szeged, H6720 Szeged, Hungary
- HAS-USZ Momentum Epithelial Cell Signaling and Secretion Research Group, University of Szeged, H6720 Szeged, Hungary
- HCEMM-SZTE Molecular Gastroenterology Research Group, University of Szeged, H6720 Szeged, Hungary
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10
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Hewlett B, Singh NP, Vannier C, Galli T. ER-PM Contact Sites - SNARING Actors in Emerging Functions. Front Cell Dev Biol 2021; 9:635518. [PMID: 33681218 PMCID: PMC7928305 DOI: 10.3389/fcell.2021.635518] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 01/21/2021] [Indexed: 11/13/2022] Open
Abstract
The compartmentalisation achieved by confining cytoplasm into membrane-enclosed organelles in eukaryotic cells is essential for maintaining vital functions including ATP production, synthetic and degradative pathways. While intracellular organelles are highly specialised in these functions, the restricting membranes also impede exchange of molecules responsible for the synchronised and responsive cellular activities. The initial identification of contact sites between the ER and plasma membrane (PM) provided a potential candidate structure for communication between organelles without mixing by fusion. Over the past decades, research has revealed a far broader picture of the events. Membrane contact sites (MCSs) have been recognized as increasingly important actors in cell differentiation, plasticity and maintenance, and, upon dysfunction, responsible for pathological conditions such as cancer and neurodegenerative diseases. Present in multiple organelles and cell types, MCSs promote transport of lipids and Ca2+ homoeostasis, with a range of associated protein families. Interestingly, each MCS displays a unique molecular signature, adapted to organelle functions. This review will explore the literature describing the molecular components and interactions taking place at ER-PM contact sites, their functions, and implications in eukaryotic cells, particularly neurons, with emphasis on lipid transfer proteins and emerging function of SNAREs.
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Affiliation(s)
- Bailey Hewlett
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France
| | - Neha Pratap Singh
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France
| | - Christian Vannier
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France
| | - Thierry Galli
- INSERM U1266, Institut de Psychiatrie et Neurosciences de Paris, Université de Paris, Paris, France.,GHU PARIS Psychiatrie and Neurosciences, Paris, France
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11
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Li C, Qian T, He R, Wan C, Liu Y, Yu H. Endoplasmic Reticulum-Plasma Membrane Contact Sites: Regulators, Mechanisms, and Physiological Functions. Front Cell Dev Biol 2021; 9:627700. [PMID: 33614657 PMCID: PMC7889955 DOI: 10.3389/fcell.2021.627700] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/13/2021] [Indexed: 12/13/2022] Open
Abstract
The endoplasmic reticulum (ER) forms direct membrane contact sites with the plasma membrane (PM) in eukaryotic cells. These ER-PM contact sites play essential roles in lipid homeostasis, ion dynamics, and cell signaling, which are carried out by protein-protein or protein-lipid interactions. Distinct tethering factors dynamically control the architecture of ER-PM junctions in response to intracellular signals or external stimuli. The physiological roles of ER-PM contact sites are dependent on a variety of regulators that individually or cooperatively perform functions in diverse cellular processes. This review focuses on proteins functioning at ER-PM contact sites and highlights the recent progress in their mechanisms and physiological roles.
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Affiliation(s)
- Chenlu Li
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Tiantian Qian
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Ruyue He
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Chun Wan
- Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, CO, United States
| | - Yinghui Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
| | - Haijia Yu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, China
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12
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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] [MESH Headings] [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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Affiliation(s)
- Shiyin Lin
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China
| | - Tian Meng
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China
| | - Haofeng Huang
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China
| | - Haixia Zhuang
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China
| | - Zhengjie He
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China
| | - Huan Yang
- Department of Pulmonary and Critical Care Medicine, Hunan Provincial People's Hospital, The First Affiliated Hospital of Hunan Normal University, Changsha 410021, China
| | - Du Feng
- Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou Municipal and Guangdong Provincial Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Medical University, 511436, Guangzhou, China
- State Key Laboratory of Respiratory Disease, Guangzhou Medical University, 511436, Guangzhou, China
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13
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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: 26] [Impact Index Per Article: 6.5] [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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14
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Petkovic M, Oses-Prieto J, Burlingame A, Jan LY, Jan YN. TMEM16K is an interorganelle regulator of endosomal sorting. Nat Commun 2020; 11:3298. [PMID: 32620747 PMCID: PMC7335067 DOI: 10.1038/s41467-020-17016-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 06/05/2020] [Indexed: 12/17/2022] Open
Abstract
Communication between organelles is essential for their cellular homeostasis. Neurodegeneration reflects the declining ability of neurons to maintain cellular homeostasis over a lifetime, where the endolysosomal pathway plays a prominent role by regulating protein and lipid sorting and degradation. Here we report that TMEM16K, an endoplasmic reticulum lipid scramblase causative for spinocerebellar ataxia (SCAR10), is an interorganelle regulator of the endolysosomal pathway. We identify endosomal transport as a major functional cluster of TMEM16K in proximity biotinylation proteomics analyses. TMEM16K forms contact sites with endosomes, reconstituting split-GFP with the small GTPase RAB7. Our study further implicates TMEM16K lipid scrambling activity in endosomal sorting at these sites. Loss of TMEM16K function led to impaired endosomal retrograde transport and neuromuscular function, one of the symptoms of SCAR10. Thus, TMEM16K-containing ER-endosome contact sites represent clinically relevant platforms for regulating endosomal sorting.
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Affiliation(s)
- Maja Petkovic
- Departments of Physiology, Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, 94158, USA.
| | - Juan Oses-Prieto
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Alma Burlingame
- Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, CA, 94158, USA
| | - Lily Yeh Jan
- Departments of Physiology, Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, 94158, USA
- Howard Hughes Medical Institute, University of California, San Francisco, CA, USA
| | - Yuh Nung Jan
- Departments of Physiology, Biochemistry and Biophysics, University of California at San Francisco, San Francisco, CA, 94158, USA.
- Howard Hughes Medical Institute, University of California, San Francisco, CA, USA.
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15
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Targeting of Intracellular TMEM16 Proteins to the Plasma Membrane and Activation by Purinergic Signaling. Int J Mol Sci 2020; 21:ijms21114065. [PMID: 32517157 PMCID: PMC7312528 DOI: 10.3390/ijms21114065] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 05/31/2020] [Accepted: 06/02/2020] [Indexed: 11/22/2022] Open
Abstract
Anoctamins such as TMEM16A and TMEM16B are Ca2+-dependent Cl− channels activated through purinergic receptor signaling. TMEM16A (ANO1), TMEM16B (ANO2) and TMEM16F (ANO6) are predominantly expressed at the plasma membrane and are therefore well accessible for functional studies. While TMEM16A and TMEM16B form halide-selective ion channels, TMEM16F and probably TMEM16E operate as phospholipid scramblases and nonselective ion channels. Other TMEM16 paralogs are expressed mainly in intracellular compartments and are therefore difficult to study at the functional level. Here, we report that TMEM16E (ANO5), -H (ANO8), -J (ANO9) and K (ANO10) are targeted to the plasma membrane when fused to a C-terminal CAAX (cysteine, two aliphatic amino acids plus methionin, serine, alanin, cystein or glutamin) motif. These paralogs produce Ca2+-dependent ion channels. Surprisingly, expression of the TMEM16 paralogs in the plasma membrane did not produce additional scramblase activity. In contrast, endogenous scrambling induced by stimulation of purinergic P2X7 receptors was attenuated, in parallel with reduced plasma membrane blebbing. This could suggest that intracellular TMEM16 paralogs operate differently when compared to plasma membrane-localized TMEM16F, and may even stabilize intracellular membranes. Alternatively, CAAX tagging, which leads to expression in non-raft compartments of the plasma membrane, may antagonize phosphatidylserine exposure by endogenous raft-located TMEM16F. CAAX-containing constructs may be useful to further investigate the molecular properties of intracellular TMEM16 proteins.
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16
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D'Ambrosio JM, Albanèse V, Lipp NF, Fleuriot L, Debayle D, Drin G, Čopič A. Osh6 requires Ist2 for localization to ER-PM contacts and efficient phosphatidylserine transport in budding yeast. J Cell Sci 2020; 133:jcs.243733. [PMID: 32327560 DOI: 10.1242/jcs.243733] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 04/06/2020] [Indexed: 11/20/2022] Open
Abstract
Osh6 and Osh7 are lipid transfer proteins (LTPs) that move phosphatidylserine (PS) from the endoplasmic reticulum (ER) to the plasma membrane (PM). High PS levels at the PM are key for many cellular functions. Intriguingly, Osh6 and Osh7 localize to ER-PM contact sites, although they lack membrane-targeting motifs, in contrast to multidomain LTPs that both bridge membranes and convey lipids. We show that Osh6 localization to contact sites depends on its interaction with the cytosolic tail of the ER-PM tether Ist2, a homolog of TMEM16 proteins. We identify a motif in the Ist2 tail, conserved in yeasts, as the Osh6-binding region, and we map an Ist2-binding surface on Osh6. Mutations in the Ist2 tail phenocopy osh6Δ osh7Δ deletion: they decrease cellular PS levels and block PS transport to the PM. Our study unveils an unexpected partnership between a TMEM16-like protein and a soluble LTP, which together mediate lipid transport at contact sites.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
| | - Véronique Albanèse
- Université de Paris, CNRS, Institut Jacques Monod, F-75006, Paris, France
| | - Nicolas-Frédéric Lipp
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS and Université Côte d'Azur, 06560 Valbonne, France
| | - Lucile Fleuriot
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS and Université Côte d'Azur, 06560 Valbonne, France
| | - Delphine Debayle
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS and Université Côte d'Azur, 06560 Valbonne, France
| | - Guillaume Drin
- Institut de Pharmacologie Moléculaire et Cellulaire, CNRS and Université Côte d'Azur, 06560 Valbonne, France
| | - Alenka Čopič
- Université de Paris, CNRS, Institut Jacques Monod, F-75006, Paris, France
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17
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Ahuja M, Chung WY, Lin WY, McNally BA, Muallem S. Ca 2+ Signaling in Exocrine Cells. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035279. [PMID: 31636079 DOI: 10.1101/cshperspect.a035279] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Calcium (Ca2+) and cyclic AMP (cAMP) signaling cross talk and synergize to stimulate the cardinal functions of exocrine cells, regulated exocytosis, and fluid and electrolyte secretion. This physiological process requires the organization of the two signaling pathways into complexes at defined cellular domains and close placement. Such domains are formed by membrane contact sites (MCS). This review discusses the basic properties of Ca2+ signaling in exocrine cells, the role of MCS in the organization of cell signaling and in cross talk and synergism between the Ca2+ and cAMP signaling pathways and, finally, the mechanism by which the Ca2+ and cAMP pathways synergize to stimulate epithelial fluid and electrolyte secretion.
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Affiliation(s)
- Malini Ahuja
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, Maryland 20892
| | - Woo Young Chung
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, Maryland 20892
| | - Wei-Yin Lin
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, Maryland 20892
| | - Beth A McNally
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, Maryland 20892
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institute of Health, Bethesda, Maryland 20892
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18
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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: 67] [Impact Index Per Article: 13.4] [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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19
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Jha A, Chung WY, Vachel L, Maleth J, Lake S, Zhang G, Ahuja M, Muallem S. Anoctamin 8 tethers endoplasmic reticulum and plasma membrane for assembly of Ca 2+ signaling complexes at the ER/PM compartment. EMBO J 2019; 38:embj.2018101452. [PMID: 31061173 DOI: 10.15252/embj.2018101452] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 04/03/2019] [Accepted: 04/05/2019] [Indexed: 12/18/2022] Open
Abstract
Communication and material transfer between membranes and organelles take place at membrane contact sites (MCSs). MCSs between the ER and PM, the ER/PM junctions, are the sites where the ER Ca2+ sensor STIM1 and the PM Ca2+ influx channel Orai1 cluster. MCSs are formed by tether proteins that bridge the opposing membranes, but the identity and role of these tethers in receptor-evoked Ca2+ signaling is not well understood. Here, we identified Anoctamin 8 (ANO8) as a key tether in the formation of the ER/PM junctions that is essential for STIM1-STIM1 interaction and STIM1-Orai1 interaction and channel activation at a ER/PM PI(4,5)P2-rich compartment. Moreover, ANO8 assembles all core Ca2+ signaling proteins: Orai1, PMCA, STIM1, IP3 receptors, and SERCA2 at the ER/PM junctions to mediate a novel form of Orai1 channel inactivation by markedly facilitating SERCA2-mediated Ca2+ influx into the ER. This controls the efficiency of receptor-stimulated Ca2+ signaling, Ca2+ oscillations, and duration of Orai1 activity to prevent Ca2+ toxicity. These findings reveal the central role of MCSs in determining efficiency and fidelity of cell signaling.
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Affiliation(s)
- Archana Jha
- The Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Woo Young Chung
- The Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Laura Vachel
- The Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Jozsef Maleth
- First Department of Medicine, University of Szeged, Szeged, Hungary
| | - Sarah Lake
- The Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Guofeng Zhang
- Trans-NIH Shared Resource on Biomedical Engineering and Physical Science (BEPS) National Institute of Biomedical Imaging & Bioengineering, Bethesda, MD, USA
| | - Malini Ahuja
- The Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
| | - Shmuel Muallem
- The Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, USA
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20
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Regulation of targeting determinants in interorganelle communication. Curr Opin Cell Biol 2019; 57:106-114. [PMID: 30807956 DOI: 10.1016/j.ceb.2018.12.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 12/27/2018] [Accepted: 12/28/2018] [Indexed: 01/02/2023]
Abstract
The field of interorganelle communication is now established as a major aspect of intracellular organisation, with a profusion of material and signals exchanged between organelles. One way to address interorganelle communication is to study the interactions of the proteins involved, particularly targeting interactions, which are a key way to regulate activity. While most peripheral membrane proteins have single determinants for membrane targeting, proteins involved in interorganelle communication have more than one such determinant, sometimes as many as four, as in Vps13. Here we review the targeting determinants, showing how they can be relatively hard to find, how they are regulated, and how proteins integrate information from multiple targeting determinants.
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21
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Molino D, Nascimbeni AC, Giordano F, Codogno P, Morel E. ER-driven membrane contact sites: Evolutionary conserved machineries for stress response and autophagy regulation? Commun Integr Biol 2017; 10:e1401699. [PMID: 29259731 PMCID: PMC5731517 DOI: 10.1080/19420889.2017.1401699] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 10/20/2017] [Accepted: 10/31/2017] [Indexed: 10/26/2022] Open
Abstract
Endoplasmic Reticulum (ER), spreading in the whole cell cytoplasm, is a central player in eukaryotic cell homeostasis, from plants to mammals. Beside crucial functions, such as membrane lipids and proteins synthesis and outward transport, the ER is able to connect to virtually every endomembrane compartment by specific tethering molecular machineries, which enables the establishment of membrane-membrane contact sites. ER-mitochondria contact sites have been shown to be involved in autophagosome biogenesis, the main organelle of the autophagy degradation pathway. More recently we demonstrated that also ER-plasma membrane contact sites are sites for autophagosomes assembly, suggesting that more generally ER-organelles contacts are involved in autophagy and organelle biogenesis. Here we aim to discuss the functioning of ER-driven contact sites in mammals and plants and more in particular emphasize on their recently highlighted function in autophagy to finally conclude on some key questions that may be useful for further research in the field.
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Affiliation(s)
- Diana Molino
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR.,Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Anna Chiara Nascimbeni
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR.,Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Francesca Giordano
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Patrice Codogno
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR.,Université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Etienne Morel
- Institut Necker-Enfants Malades (INEM), INSERM U1151-CNRS UMR.,Université Paris Descartes-Sorbonne Paris Cité, Paris, France
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22
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Cabrita I, Benedetto R, Fonseca A, Wanitchakool P, Sirianant L, Skryabin BV, Schenk LK, Pavenstädt H, Schreiber R, Kunzelmann K. Differential effects of anoctamins on intracellular calcium signals. FASEB J 2017; 31:2123-2134. [PMID: 28183802 DOI: 10.1096/fj.201600797rr] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 01/23/2017] [Indexed: 01/04/2023]
Abstract
The Ca2+-activated Cl- channel TMEM16A [anoctamin (ANO)1] is homologous to yeast Ist2 and has been shown to tether the cortical endoplasmic reticulum (ER) to the plasma membrane. We therefore examined whether ANO1 and other members of the ANO family affect intracellular Ca2+ ([Ca2+]i) signals. It is shown that expression of ANO1 augments Ca2+ store release upon stimulation of GPCRs, whereas knockdown of ANO1, or lack of Ano1 expression in Ano1-/- animals, as shown in an earlier report, inhibits Ca2+ release. ANO6, and -10 show similar effects, whereas expression of ANO4, -8, and -9 attenuate filling of the ER store. The impact of ANO1 and -4 were examined in more detail. ANO1 colocalized and interacted with IP3R, whereas ANO4 colocalized with SERCA Ca2+ pumps and interacted with ORAI-1 channels, respectively. ANO1 Cl currents were rapidly activated exclusively through Ca2+ store release, and remained untouched by influx of extracellular Ca2+ In contrast expression of ANO4 caused a delayed activation of membrane-localized ANO6 channels, solely through store-operated Ca2+ entry via ORAI. Ca2+ signals were inhibited by knocking down expression of endogenous ANO1, -5, -6, and -10 and were also reduced in epithelial cells from Ano10-/- mice. The data suggest that ANOs affect compartmentalized [Ca2+]i signals, which may explain some of the cellular defects related to ANO mutations.-Cabrita, I., Benedetto, R., Fonseca, A., Wanitchakool, P., Sirianant, L., Skryabin, B. V., Schenk, L. K., Pavenstädt, H., Schreiber, R., Kunzelmann, K. Differential effects of anoctamins on intracellular calcium signals.
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Affiliation(s)
- Inês Cabrita
- Physiological Institute, University of Regensburg, Regensburg, Germany;
| | - Roberta Benedetto
- Physiological Institute, University of Regensburg, Regensburg, Germany
| | - Ana Fonseca
- Physiological Institute, University of Regensburg, Regensburg, Germany
| | | | - Lalida Sirianant
- Physiological Institute, University of Regensburg, Regensburg, Germany
| | - Boris V Skryabin
- Department of Medicine (TRAM), University of Münster, Münster, Germany; and
| | - Laura K Schenk
- Department of Internal Medicine D, Universitätsklinikum Münster, Albert-Schweitzer-Campus, Münster, Germany
| | - Hermann Pavenstädt
- Department of Internal Medicine D, Universitätsklinikum Münster, Albert-Schweitzer-Campus, Münster, Germany
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, Regensburg, Germany
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, Regensburg, Germany;
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23
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Popov-Čeleketić D, Bianchi F, Ruiz SJ, Meutiawati F, Poolman B. A Plasma Membrane Association Module in Yeast Amino Acid Transporters. J Biol Chem 2016; 291:16024-37. [PMID: 27226538 DOI: 10.1074/jbc.m115.706770] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Indexed: 12/22/2022] Open
Abstract
Amino acid permeases (AAPs) in the plasma membrane (PM) of Saccharomyces cerevisiae are responsible for the uptake of amino acids and involved in regulation of their cellular levels. Here, we report on a strong and complex module for PM association found in the C-terminal tail of AAPs. Using in silico analyses and mutational studies we found that the C-terminal sequences of Gap1, Bap2, Hip1, Tat1, Tat2, Mmp1, Sam3, Agp1, and Gnp1 are about 50 residues long, associate with the PM, and have features that discriminate them from the termini of organellar amino acid transporters. We show that this sequence (named PMasseq) contains an amphipathic α-helix and the FWC signature, which is palmitoylated by palmitoyltransferase Pfa4. Variations of PMasseq, found in different AAPs, lead to different mobilities and localization patterns, whereas the disruption of the sequence has an adverse effect on cell viability. We propose that PMasseq modulates the function and localization of AAPs along the PM. PMasseq is one of the most complex protein signals for plasma membrane association across species and can be used as a delivery vehicle for the PM.
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Affiliation(s)
- Dušan Popov-Čeleketić
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Frans Bianchi
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Stephanie J Ruiz
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Febrina Meutiawati
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Bert Poolman
- From the Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
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24
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New Insight Into the Roles of Membrane Microdomains in Physiological Activities of Fungal Cells. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 325:119-80. [PMID: 27241220 DOI: 10.1016/bs.ircmb.2016.02.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The organization of biological membranes into structurally and functionally distinct lateral microdomains is generally accepted. From bacteria to mammals, laterally compartmentalized membranes seem to be a vital attribute of life. The crucial fraction of our current knowledge about the membrane microdomains has been gained from studies on fungi. In this review we summarize the evidence of the microdomain organization of membranes from fungal cells, with accent on their enormous diversity in composition, temporal dynamics, modes of formation, and recognized engagement in the cell physiology. A special emphasis is laid on the fact that in addition to their other biological functions, membrane microdomains also mediate the communication among different membranes within a eukaryotic cell and coordinate their functions. Involvement of fungal membrane microdomains in stress sensing, regulation of lipid homeostasis, and cell differentiation is discussed more in detail.
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25
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Son A, Park S, Shin DM, Muallem S. Orai1 and STIM1 in ER/PM junctions: roles in pancreatic cell function and dysfunction. Am J Physiol Cell Physiol 2016; 310:C414-22. [PMID: 26739495 DOI: 10.1152/ajpcell.00349.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Membrane contact sites (MCS) are critical junctions that form between the endoplasmic reticulum (ER) and membranes of various organelles, including the plasma membrane (PM). Signaling complexes, including mediators of Ca(2+) signaling, are assembled within MCS, such as the ER/PM junction. This is most evident in polarized epithelial cells, such as pancreatic cells. Core Ca(2+) signaling proteins cluster at the apical pole, the site of inositol 1,4,5-trisphosphate-mediated Ca(2+) release and Orai1/transient receptor potential canonical-mediated store-dependent Ca(2+) entry. Recent advances have characterized the proteins that tether the membranes at MCS and the role of these proteins in modulating physiological and pathological intracellular signaling. This review discusses recent advances in the characterization of Ca(2+) signaling at ER/PM junctions and the relation of these junctions to physiological and pathological Ca(2+) signaling in pancreatic acini.
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Affiliation(s)
- Aran Son
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Seonghee Park
- Department of Physiology, School of Medicine, Ewha Womans University, Seoul, Korea
| | - Dong Min Shin
- Department of Oral Biology, BK 21 PLUS Project, Yonsei University College of Dentistry, Seoul, Korea
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland;
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26
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TMEM110 regulates the maintenance and remodeling of mammalian ER-plasma membrane junctions competent for STIM-ORAI signaling. Proc Natl Acad Sci U S A 2015; 112:E7083-92. [PMID: 26644574 DOI: 10.1073/pnas.1521924112] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The stromal interaction molecule (STIM)-ORAI calcium release-activated calcium modulator (ORAI) pathway controls store-dependent calcium entry, a major mechanism of physiological calcium signaling in mammalian cells. The core elements of the pathway are the regulatory protein STIM1, located in the endoplasmic reticulum (ER) membrane, the calcium channel ORAI1 in the plasma membrane, and sites of close contact between the ER and the plasma membrane that permit the two proteins to interact. Research on calcium signaling has centered on STIM1, ORAI1, and a few proteins that directly modulate STIM-ORAI function. However, little is known about proteins that organize ER-plasma membrane junctions for STIM-ORAI-dependent calcium signaling. Here, we report that an ER-resident membrane protein identified in a previous genome-wide RNAi screen, transmembrane protein 110 (TMEM110), regulates the long-term maintenance of ER-plasma membrane junctions and the short-term physiological remodeling of the junctions during store-dependent calcium signaling.
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Kralt A, Carretta M, Mari M, Reggiori F, Steen A, Poolman B, Veenhoff LM. Intrinsically Disordered Linker and Plasma Membrane-Binding Motif Sort Ist2 and Ssy1 to Junctions. Traffic 2014; 16:135-47. [DOI: 10.1111/tra.12243] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 11/17/2014] [Accepted: 11/18/2014] [Indexed: 12/25/2022]
Affiliation(s)
- Annemarie Kralt
- European Institute for the Biology of Ageing (ERIBA); University of Groningen, University Medical Center Groningen, Netherlands Proteomics Centre; Antonius Deusinglaan 1 9713 AV Groningen The Netherlands
| | - Marco Carretta
- European Institute for the Biology of Ageing (ERIBA); University of Groningen, University Medical Center Groningen, Netherlands Proteomics Centre; Antonius Deusinglaan 1 9713 AV Groningen The Netherlands
- Current address: Department of Hematology, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Muriel Mari
- Department of Cell Biology; Center for Molecular Medicine, University Medical Center Utrecht; Heidelberglaan 100 3584 CX Utrecht The Netherlands
| | - Fulvio Reggiori
- Department of Cell Biology; Center for Molecular Medicine, University Medical Center Utrecht; Heidelberglaan 100 3584 CX Utrecht The Netherlands
| | - Anton Steen
- European Institute for the Biology of Ageing (ERIBA); University of Groningen, University Medical Center Groningen, Netherlands Proteomics Centre; Antonius Deusinglaan 1 9713 AV Groningen The Netherlands
| | - Bert Poolman
- Department of Biochemistry; University of Groningen; Nijenborgh 4 9747 AG Groningen The Netherlands
| | - Liesbeth M. Veenhoff
- European Institute for the Biology of Ageing (ERIBA); University of Groningen, University Medical Center Groningen, Netherlands Proteomics Centre; Antonius Deusinglaan 1 9713 AV Groningen The Netherlands
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28
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Bill A, Popa MO, van Diepen MT, Gutierrez A, Lilley S, Velkova M, Acheson K, Choudhury H, Renaud NA, Auld DS, Gosling M, Groot-Kormelink PJ, Gaither LA. Variomics screen identifies the re-entrant loop of the calcium-activated chloride channel ANO1 that facilitates channel activation. J Biol Chem 2014; 290:889-903. [PMID: 25425649 DOI: 10.1074/jbc.m114.618140] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The calcium-activated chloride channel ANO1 regulates multiple physiological processes. However, little is known about the mechanism of channel gating and regulation of ANO1 activity. Using a high-throughput, random mutagenesis-based variomics screen, we generated and functionally characterized ∼6000 ANO1 mutants and identified novel mutations that affected channel activity, intracellular trafficking, or localization of ANO1. Mutations such as S741T increased ANO1 calcium sensitivity and rendered ANO1 calcium gating voltage-independent, demonstrating a critical role of the re-entrant loop in coupling calcium and voltage sensitivity of ANO1 and hence in regulating ANO1 activation. Our data present the first unbiased and comprehensive study of the structure-function relationship of ANO1. The novel ANO1 mutants reported have diverse functional characteristics, providing new tools to study ANO1 function in biological systems, paving the path for a better understanding of the function of ANO1 and its role in health and diseases.
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Affiliation(s)
- Anke Bill
- From the Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - M Oana Popa
- the Novartis Institutes for Biomedical Research, Horsham, West Sussex RH12 5AB, United Kingdom, and
| | - Michiel T van Diepen
- the Novartis Institutes for Biomedical Research, Horsham, West Sussex RH12 5AB, United Kingdom, and
| | - Abraham Gutierrez
- From the Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - Sarah Lilley
- the Novartis Institutes for Biomedical Research, Horsham, West Sussex RH12 5AB, United Kingdom, and
| | - Maria Velkova
- the Novartis Institutes for Biomedical Research, Horsham, West Sussex RH12 5AB, United Kingdom, and
| | - Kathryn Acheson
- the Novartis Institutes for Biomedical Research, Horsham, West Sussex RH12 5AB, United Kingdom, and
| | - Hedaythul Choudhury
- the Novartis Institutes for Biomedical Research, Horsham, West Sussex RH12 5AB, United Kingdom, and
| | - Nicole A Renaud
- From the Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - Douglas S Auld
- From the Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139
| | - Martin Gosling
- the Novartis Institutes for Biomedical Research, Horsham, West Sussex RH12 5AB, United Kingdom, and
| | | | - L Alex Gaither
- From the Novartis Institutes for Biomedical Research, Cambridge, Massachusetts 02139,
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29
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Wolf W, Meese K, Seedorf M. Ist2 in the yeast cortical endoplasmic reticulum promotes trafficking of the amino acid transporter Bap2 to the plasma membrane. PLoS One 2014; 9:e85418. [PMID: 24416406 PMCID: PMC3885692 DOI: 10.1371/journal.pone.0085418] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 11/26/2013] [Indexed: 11/18/2022] Open
Abstract
The equipment of the plasma membrane in Saccharomyces cerevisiae with specific nutrient transporters is highly regulated by transcription, translation and protein trafficking allowing growth in changing environments. The activity of these transporters depends on a H+ gradient across the plasma membrane generated by the H+-ATPase Pma1. We found that the polytopic membrane protein Ist2 in the cortical endoplasmic reticulum (ER) is required for efficient leucine uptake during the transition from fermentation to respiration. Experiments employing tandem fluorescence timer protein tag showed that Ist2 was necessary for efficient trafficking of newly synthesized leucine transporter Bap2 from the ER to the plasma membrane. This finding explains the growth defect of ist2Δ mutants during nutritional challenges and illustrates the important role of physical coupling between cortical ER and plasma membrane.
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Affiliation(s)
- Wendelin Wolf
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH-Allianz, Heidelberg, Germany
| | - Klaus Meese
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH-Allianz, Heidelberg, Germany
| | - Matthias Seedorf
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH-Allianz, Heidelberg, Germany
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30
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Helle SC, Kanfer G, Kolar K, Lang A, Michel AH, Kornmann B. Organization and function of membrane contact sites. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - MOLECULAR CELL RESEARCH 2013. [DOI: 10.1016.j.bbamcr.2013.01.02810.1016/j.bbamcr.2013.01.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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31
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Oligomerization and Ca2+/calmodulin control binding of the ER Ca2+-sensors STIM1 and STIM2 to plasma membrane lipids. Biosci Rep 2013; 33:BSR20130089. [PMID: 24044355 PMCID: PMC3814058 DOI: 10.1042/bsr20130089] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Ca2+ (calcium) homoeostasis and signalling rely on physical contacts between Ca2+ sensors in the ER (endoplasmic reticulum) and Ca2+ channels in the PM (plasma membrane). STIM1 (stromal interaction molecule 1) and STIM2 Ca2+ sensors oligomerize upon Ca2+ depletion in the ER lumen, contact phosphoinositides at the PM via their cytosolic lysine (K)-rich domains, and activate Ca2+ channels. Differential sensitivities of STIM1 and STIM2 towards ER luminal Ca2+ have been studied but responses towards elevated cytosolic Ca2+ concentration and the mechanism of lipid binding remain unclear. We found that tetramerization of the STIM1 K-rich domain is necessary for efficient binding to PI(4,5)P2-containing PM-like liposomes consistent with an oligomerization-driven STIM1 activation. In contrast, dimerization of STIM2 K-rich domain was sufficient for lipid binding. Furthermore, the K-rich domain of STIM2, but not of STIM1, forms an amphipathic α-helix. These distinct features of the STIM2 K-rich domain cause an increased affinity for PI(4,5)P2, consistent with the lower activation threshold of STIM2 and a function as regulator of basal Ca2+ levels. Concomitant with higher affinity for PM lipids, binding of CaM (calmodulin) inhibited the interaction of the STIM2 K-rich domain with liposomes in a Ca2+ and PI(4,5)P2 concentration-dependent manner. Therefore we suggest that elevated cytosolic Ca2+ concentration down-regulates STIM2-mediated ER–PM contacts via CaM binding.
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32
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Helle SCJ, Kanfer G, Kolar K, Lang A, Michel AH, Kornmann B. Organization and function of membrane contact sites. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2013; 1833:2526-41. [PMID: 23380708 DOI: 10.1016/j.bbamcr.2013.01.028] [Citation(s) in RCA: 329] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 01/18/2013] [Accepted: 01/21/2013] [Indexed: 11/16/2022]
Abstract
Membrane-bound organelles are a wonderful evolutionary acquisition of the eukaryotic cell, allowing the segregation of sometimes incompatible biochemical reactions into specific compartments with tailored microenvironments. On the flip side, these isolating membranes that crowd the interior of the cell, constitute a hindrance to the diffusion of metabolites and information to all corners of the cell. To ensure coordination of cellular activities, cells use a network of contact sites between the membranes of different organelles. These membrane contact sites (MCSs) are domains where two membranes come to close proximity, typically less than 30nm. Such contacts create microdomains that favor exchange between two organelles. MCSs are established and maintained in durable or transient states by tethering structures, which keep the two membranes in proximity, but fusion between the membranes does not take place. Since the endoplasmic reticulum (ER) is the most extensive cellular membrane network, it is thus not surprising to find the ER involved in most MCSs within the cell. The ER contacts diverse compartments such as mitochondria, lysosomes, lipid droplets, the Golgi apparatus, endosomes and the plasma membrane. In this review, we will focus on the common organizing principles underlying the many MCSs found between the ER and virtually all compartments of the cell, and on how the ER establishes a network of MCSs for the trafficking of vital metabolites and information. This article is part of a Special Issue entitled: Functional and structural diversity of endoplasmic reticulum.
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Affiliation(s)
- Sebastian C J Helle
- Institute of Biochemistry, ETH Zürich, HPM G16 Schafmattstrasse, Zürich, Switzerland
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33
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Yeast Ist2 recruits the endoplasmic reticulum to the plasma membrane and creates a ribosome-free membrane microcompartment. PLoS One 2012; 7:e39703. [PMID: 22808051 PMCID: PMC3392263 DOI: 10.1371/journal.pone.0039703] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 05/24/2012] [Indexed: 11/19/2022] Open
Abstract
The endoplasmic reticulum (ER) forms contacts with the plasma membrane. These contacts are known to function in non-vesicular lipid transport and signaling. Ist2 resides in specific domains of the ER in Saccharomyces cerevisiae where it binds phosphoinositide lipids at the cytosolic face of the plasma membrane. Here, we report that Ist2 recruits domains of the yeast ER to the plasma membrane. Ist2 determines the amount of cortical ER present and the distance between the ER and the plasma membrane. Deletion of IST2 resulted in an increased distance between ER and plasma membrane and allowed access of ribosomes to the space between the two membranes. Cells that overexpress Ist2 showed an association of the nucleus with the plasma membrane. The morphology of the ER and yeast growth were sensitive to the abundance of Ist2. Moreover, Ist2-dependent effects on cytosolic pH and genetic interactions link Ist2 to the activity of the H(+) pump Pma1 in the plasma membrane during cellular adaptation to the growth phase of the culture. Consistently we found a partial colocalization of Ist2-containing cortical ER and Pma1-containing domains of the plasma membrane. Hence Ist2 may be critically positioned in domains that couple functions of the ER and the plasma membrane.
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34
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Gidda SK, Shockey JM, Falcone M, Kim PK, Rothstein SJ, Andrews DW, Dyer JM, Mullen RT. Hydrophobic-domain-dependent protein-protein interactions mediate the localization of GPAT enzymes to ER subdomains. Traffic 2011; 12:452-72. [PMID: 21214700 DOI: 10.1111/j.1600-0854.2011.01160.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The endoplasmic reticulum (ER) is a dynamic organelle that consists of numerous regions or 'subdomains' that have discrete morphological features and functional properties. Although it is generally accepted that these subdomains differ in their protein and perhaps lipid compositions, a clear understanding of how they are assembled and maintained has not been well established. We previously demonstrated that two diacylglycerol acyltransferase enzymes (DGAT1 and DGAT2) from tung tree (Vernicia fordii) were located in different subdomains of ER, but the mechanisms responsible for protein targeting to these subdomains were not elucidated. Here we extend these studies by describing two glycerol-3-phosphate acyltransferase-like (GPAT) enzymes from tung tree, GPAT8 and GPAT9, that both colocalize with DGAT2 in the same ER subdomains. Measurement of protein-protein interactions using the split-ubiquitin assay revealed that GPAT8 interacts with itself, GPAT9 and DGAT2, but not with DGAT1. Furthermore, mutational analysis of GPAT8 revealed that the protein's first predicted hydrophobic region, which contains an amphipathic helix-like motif, is required for interaction with DGAT2 and for DGAT2-dependent colocalization in ER subdomains. Taken together, these results suggest that the regulation and organization of ER subdomains is mediated at least in part by higher-ordered, hydrophobic-domain-dependent homo- and hetero-oligomeric protein-protein interactions.
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Affiliation(s)
- Satinder K Gidda
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
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35
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Zahedi B, Goo HJ, Beaulieu N, Tazmini G, Kay RJ, Cornell RB. Phosphoinositide 3-kinase regulates plasma membrane targeting of the Ras-specific exchange factor RasGRP1. J Biol Chem 2011; 286:12712-23. [PMID: 21285350 DOI: 10.1074/jbc.m110.189605] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Receptor-induced targeting of exchange factors to specific cellular membranes is the predominant mechanism for initiating and compartmentalizing signal transduction by Ras GTPases. The exchange factor RasGRP1 has a C1 domain that binds the lipid diacylglycerol and thus can potentially mediate membrane localization in response to receptors that are coupled to diacylglycerol-generating phospholipase Cs. However, the C1 domain is insufficient for targeting RasGRP1 to the plasma membrane. We found that a basic/hydrophobic cluster of amino acids within the plasma membrane-targeting domain of RasGRP1 is instead responsible for plasma membrane targeting. This basic/hydrophobic cluster binds directly to phospholipid vesicles containing phosphoinositides via electrostatic interactions with polyanionic phosphoinositide headgroups and insertion of a tryptophan into the lipid bilayer. B cell antigen receptor ligation and other stimuli induce plasma membrane targeting of RasGRP1 by activating the phosphoinositide 3-kinase signaling pathway, which generates phosphoinositides within the plasma membrane. Direct detection of phosphoinositides by the basic/hydrophobic cluster of RasGRP1 provides a novel mechanism for coupling and co-compartmentalizing phosphoinositide 3-kinase and Ras signaling and, in coordination with diacylglycerol detection by the C1 domain, gives RasGRP1 the potential to serve as an integrator of converging signals from the phosphoinositide 3-kinase and phospholipase C pathways.
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Affiliation(s)
- Bari Zahedi
- Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, British Columbia V5Z 1L3
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36
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Seedorf M. Role of endoplasmic reticulum domains in determining secretion routes. F1000 BIOLOGY REPORTS 2010; 2:77. [PMID: 21173840 PMCID: PMC2981193 DOI: 10.3410/b2-77] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Distinct domains of the endoplasmic reticulum (ER) can function as entry points into different protein-sorting routes. In addition to using the classical ER-Golgi pathway, one of these unconventional routes utilizes different combinations of machinery of the classical secretory pathway and components of the autophagosomal system.
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Affiliation(s)
- Matthias Seedorf
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance Im Neuenheimer Feld 282, 69120 Heidelberg Germany
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37
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Lee SC, Wu CH, Wang CW. Traffic of a viral movement protein complex to the highly curved tubules of the cortical endoplasmic reticulum. Traffic 2010; 11:912-30. [PMID: 20374554 DOI: 10.1111/j.1600-0854.2010.01064.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Intracellular trafficking of the nonstructural movement proteins of plant viruses plays a crucial role in sequestering and targeting viral macromolecules in and between cells. Many of the movement proteins traffic in unconventional, yet mechanistically unknown, pathways to localize to the cell periphery. Here we study trafficking strategies associated with two integral membrane movement proteins TGBp2 and TGBp3 of Potexvirus in yeast. We demonstrate that this simple eukaryote recapitulates the targeting of TGBp2 to the peripheral bodies at the cell cortex by TGBp3. We found that these viral movement proteins traffic as an approximately 1:1 stoichiometric protein complex that further polymerizes to form punctate structures. Many punctate structures depart from the perinuclear endoplasmic reticulum (ER) and move along the tubular ER to the cortical ER, supporting that it involves a lateral sorting event via the ER network. Furthermore, the peripheral bodies are associated with cortical ER tubules that are marked by the ER shaping protein reticulon in both yeast and plants. Thus, our data support a model in which the peripheral bodies partition into and/or stabilize at highly curved membrane environments.
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Affiliation(s)
- Shu-Chuan Lee
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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38
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Induction of cortical endoplasmic reticulum by dimerization of a coatomer-binding peptide anchored to endoplasmic reticulum membranes. Proc Natl Acad Sci U S A 2010; 107:6876-81. [PMID: 20351264 DOI: 10.1073/pnas.1002536107] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cortical endoplasmic reticulum (cER) is a permanent feature of yeast cells but occurs transiently in most animal cell types. Ist2p is a transmembrane protein that permanently localizes to the cER in yeast. When Ist2 is expressed in mammalian cells, it induces abundant cER containing Ist2. Ist2 cytoplasmic C-terminal peptide is necessary and sufficient to induce cER. This peptide sequence resembles classic coat protein complex I (COPI) coatomer protein-binding KKXX signals, and indeed the dimerized peptide binds COPI in vitro. Controlled dimerization of this peptide induces cER in cells. RNA interference experiments confirm that coatomer is required for cER induction in vivo, as are microtubules and the microtubule plus-end binding protein EB1. We suggest that Ist2 dimerization triggers coatomer binding and clustering of this protein into domains that traffic at the microtubule growing plus-end to generate the cER beneath the plasma membrane. Sequences similar to the Ist2 lysine-rich tail are found in mammalian STIM proteins that reversibly induce the formation of cER under calcium control.
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39
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Ercan E, Momburg F, Engel U, Temmerman K, Nickel W, Seedorf M. A Conserved, Lipid-Mediated Sorting Mechanism of Yeast Ist2 and Mammalian STIM Proteins to the Peripheral ER. Traffic 2009; 10:1802-18. [PMID: 19845919 DOI: 10.1111/j.1600-0854.2009.00995.x] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Ebru Ercan
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
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40
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Current awareness on yeast. Yeast 2009. [DOI: 10.1002/yea.1623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
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41
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Fischer MA, Temmerman K, Ercan E, Nickel W, Seedorf M. Binding of Plasma Membrane Lipids Recruits the Yeast Integral Membrane Protein Ist2 to the Cortical ER. Traffic 2009; 10:1084-97. [PMID: 19453974 DOI: 10.1111/j.1600-0854.2009.00926.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Marcel André Fischer
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
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