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Paul S, Audhya A, Cui Q. Delineating the shape of COat Protein complex-II coated membrane bud. PNAS NEXUS 2024; 3:pgae305. [PMID: 39108303 PMCID: PMC11302526 DOI: 10.1093/pnasnexus/pgae305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 07/10/2024] [Indexed: 08/16/2024]
Abstract
Curvature-generating proteins that direct membrane trafficking assemble on the surface of lipid bilayers to bud transport intermediates, which move protein and lipid cargoes from one cellular compartment to another. However, it remains unclear what controls the overall shape of the membrane bud once curvature induction has begun. In vitro experiments showed that excessive concentrations of the COPII protein Sar1 promoted the formation of membrane tubules from synthetic vesicles, while COPII-coated transport intermediates in cells are generally more spherical or lobed in shape. To understand the origin of these morphological differences, we employ atomistic, coarse-grained (CG), and continuum mesoscopic simulations of membranes in the presence of multiple curvature-generating proteins. We first characterize the membrane-bending ability of amphipathic peptides derived from the amino terminus of Sar1, as a function of interpeptide angle and concentration using an atomistic bicelle simulation protocol. Then, we employ CG simulations to reveal that Sec23 and Sec24 control the relative spacing between Sar1 protomers and form the inner-coat unit through an attachment with Sar1. Finally, using dynamical triangulated surface simulations based on the Helfrich Hamiltonian, we demonstrate that the uniform distribution of spacer molecules among curvature-generating proteins is crucial to the spherical budding of the membrane. Overall, our analyses suggest a new role for Sec23, Sec24, and cargo proteins in COPII-mediated membrane budding process in which they act as spacers to preserve a dispersed arrangement of Sar1 protomers and help determine the overall shape of the membrane bud.
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Affiliation(s)
- Sanjoy Paul
- Department of Chemistry, Boston University, Boston, MA 02215, USA
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Qiang Cui
- Department of Chemistry, Boston University, Boston, MA 02215, USA
- Departments of Physics and Biomedical Engineering, Boston University, Boston, MA 02215, USA
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2
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Kasberg W, Luong P, Minushkin K, Pustova I, Swift KA, Zhao M, Audhya A. TFG regulates inner COPII coat recruitment to facilitate anterograde secretory protein transport. Mol Biol Cell 2024; 35:ar113. [PMID: 38985515 PMCID: PMC11321049 DOI: 10.1091/mbc.e24-06-0282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Accepted: 07/03/2024] [Indexed: 07/12/2024] Open
Abstract
Coat protein complex II (COPII) governs the initial steps of biosynthetic secretory protein transport from the endoplasmic reticulum (ER), facilitating the movement of a wide variety of cargoes. Here, we demonstrate that Trk-fused gene (TFG) regulates the rate at which inner COPII coat proteins are concentrated at ER subdomains. Specifically, in cells lacking TFG, the GTPase-activating protein (GAP) Sec23 accumulates more rapidly at budding sites on the ER as compared with control cells, potentially altering the normal timing of GTP hydrolysis on Sar1. Under these conditions, anterograde trafficking of several secretory cargoes is delayed, irrespective of their predicted size. We propose that TFG controls the local, freely available pool of Sec23 during COPII coat formation and limits its capacity to prematurely destabilize COPII complexes on the ER. This function of TFG enables it to act akin to a rheostat, promoting the ordered recruitment of Sec23, which is critical for efficient secretory cargo export.
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Affiliation(s)
- William Kasberg
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706
| | - Peter Luong
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706
| | - Kayla Minushkin
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706
| | - Iryna Pustova
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706
| | - Kevin A. Swift
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706
| | - Meixian Zhao
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706
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3
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Levy E, Fallet-Bianco C, Auclair N, Patey N, Marcil V, Sané AT, Spahis S. Unraveling Chylomicron Retention Disease Enhances Insight into SAR1B GTPase Functions and Mechanisms of Actions, While Shedding Light of Intracellular Chylomicron Trafficking. Biomedicines 2024; 12:1548. [PMID: 39062121 PMCID: PMC11274388 DOI: 10.3390/biomedicines12071548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2024] [Revised: 06/28/2024] [Accepted: 07/08/2024] [Indexed: 07/28/2024] Open
Abstract
Over the past three decades, significant efforts have been focused on unraveling congenital intestinal disorders that disrupt the absorption of dietary lipids and fat-soluble vitamins. The primary goal has been to gain deeper insights into intra-enterocyte sites, molecular steps, and crucial proteins/regulatory pathways involved, while simultaneously identifying novel therapeutic targets and diagnostic tools. This research not only delves into specific and rare malabsorptive conditions, such as chylomicron retention disease (CRD), but also contributes to our understanding of normal physiology through the utilization of cutting-edge cellular and animal models alongside advanced research methodologies. This review elucidates how modern techniques have facilitated the decoding of CRD gene defects, the identification of dysfunctional cellular processes, disease regulatory mechanisms, and the essential role of coat protein complex II-coated vesicles and cargo receptors in chylomicron trafficking and endoplasmic reticulum (ER) exit sites. Moreover, experimental approaches have shed light on the multifaceted functions of SAR1B GTPase, wherein loss-of-function mutations not only predispose individuals to CRD but also exacerbate oxidative stress, inflammation, and ER stress, potentially contributing to clinical complications associated with CRD. In addition to dissecting the primary disease pathology, genetically modified animal models have emerged as invaluable assets in exploring various ancillary aspects, including responses to environmental challenges such as dietary alterations, gender-specific disparities in disease onset and progression, and embryonic lethality or developmental abnormalities. In summary, this comprehensive review provides an in-depth and contemporary analysis of CRD, offering a meticulous examination of the CRD current landscape by synthesizing the latest research findings and advancements in the field.
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Affiliation(s)
- Emile Levy
- Azrieli Research Center, CHU Ste-Justine and Department of Nutrition, Université de Montréal, Montreal, QC H3T 1C5, Canada
| | - Catherine Fallet-Bianco
- Azrieli Research Center, CHU Ste-Justine and Pathology & Cell Biology, Université de Montréal, Montreal, QC H3T 1C5, Canada
| | - Nickolas Auclair
- Azrieli Research Center, CHU Ste-Justine and Pharmacology, Université de Montréal, Montreal, QC H3T 1C5, Canada
| | - Natalie Patey
- Azrieli Research Center, CHU Ste-Justine and Pathology & Cell Biology, Université de Montréal, Montreal, QC H3T 1C5, Canada
| | - Valérie Marcil
- Azrieli Research Center, CHU Ste-Justine and Department of Nutrition, Université de Montréal, Montreal, QC H3T 1C5, Canada
| | | | - Schohraya Spahis
- Azrieli Research Center, CHU Ste-Justine and Biochemistry & Molecular Medicine, Université de Montréal, Montreal, QC H3T 1C5, Canada;
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4
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Milano SN, Bayer LV, Ko JJ, Casella CE, Bratu DP. The role of ER exit sites in maintaining P-body organization and transmitting ER stress response during Drosophila melanogaster oogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.03.601952. [PMID: 39005311 PMCID: PMC11245038 DOI: 10.1101/2024.07.03.601952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Processing bodies (P-bodies) are cytoplasmic membrane-less organelles which host multiple mRNA processing events. While the fundamental principles of P-body organization are beginning to be elucidated in vitro, a nuanced understanding of how their assembly is regulated in vivo remains elusive. Here, we investigate the potential link between ER exit sites and P-bodies in Drosophila melanogaster egg chambers. Employing a combination of live and super-resolution imaging, we found that P-bodies associated with ER exit sites are larger and less mobile than cytoplasmic P-bodies, indicating that they constitute a distinct class of P-bodies which are more mature than their cytoplasmic counterparts. Moreover, we demonstrate that altering the composition of ER exit sites has differential effects on core P-body proteins (Me31B, Cup, and Trailer Hitch) suggesting a potential role for ER exit sites in P-body organization. We further show that in the absence of ER exit sites, P-body integrity is compromised and the stability and translational repression efficiency of the maternal mRNA, oskar, are reduced. Finally, we show that ER stress is communicated to P-bodies via ER exit sites, highlighting the pivotal role of ER exit sites as a bridge between membrane-bound and membrane-less organelles in ER stress response. Together, our data unveils the significance of ER exit sites not only in governing P-body organization, but also in facilitating inter-organellar communication during stress, potentially bearing implications for a variety of disease pathologies.
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Affiliation(s)
- Samantha N. Milano
- Department of Biological Sciences, Hunter College, City University of New York, NY, 10065 USA
- Program in Molecular, Cellular, and Developmental Biology, The Graduate Center, City University of New York, NY, 10016 USA
| | - Livia V. Bayer
- Department of Biological Sciences, Hunter College, City University of New York, NY, 10065 USA
| | - Julie J. Ko
- Department of Biological Sciences, Hunter College, City University of New York, NY, 10065 USA
| | - Caroline E. Casella
- Department of Biological Sciences, Hunter College, City University of New York, NY, 10065 USA
| | - Diana P. Bratu
- Department of Biological Sciences, Hunter College, City University of New York, NY, 10065 USA
- Program in Molecular, Cellular, and Developmental Biology, The Graduate Center, City University of New York, NY, 10016 USA
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5
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Xie P, Zhang H, Qin Y, Xiong H, Shi C, Zhou Z. Membrane Proteins and Membrane Curvature: Mutual Interactions and a Perspective on Disease Treatments. Biomolecules 2023; 13:1772. [PMID: 38136643 PMCID: PMC10741411 DOI: 10.3390/biom13121772] [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: 11/01/2023] [Revised: 11/30/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
The pathogenesis of various diseases often involves an intricate interplay between membrane proteins and membrane curvature. Understanding the underlying mechanisms of this interaction could offer novel perspectives on disease treatment. In this review, we provide an introduction to membrane curvature and its association with membrane proteins. Furthermore, we delve into the impact and potential implications of this interaction in the context of disease treatment. Lastly, we discuss the prospects and challenges associated with harnessing these interactions for effective disease management, aiming to provide fresh insights into therapeutic strategies.
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Affiliation(s)
| | | | | | | | | | - Zijian Zhou
- State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory & Center for Molecular Imaging and Translational Medicine, School of Public Health, Shenzhen Research Institute of Xiamen University, Xiamen University, Xiamen 361102, China; (P.X.); (H.Z.); (Y.Q.); (H.X.); (C.S.)
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6
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Kasberg W, Luong P, Swift KA, Audhya A. Nutrient deprivation alters the rate of COPII subunit recruitment at ER subdomains to tune secretory protein transport. Nat Commun 2023; 14:8140. [PMID: 38066006 PMCID: PMC10709328 DOI: 10.1038/s41467-023-44002-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Co-assembly of the multilayered coat protein complex II (COPII) with the Sar1 GTPase at subdomains of the endoplasmic reticulum (ER) enables secretory cargoes to be concentrated efficiently within nascent transport intermediates, which subsequently deliver their contents to ER-Golgi intermediate compartments. Here, we define the spatiotemporal accumulation of native COPII subunits and secretory cargoes at ER subdomains under differing nutrient availability conditions using a combination of CRISPR/Cas9-mediated genome editing and live cell imaging. Our findings demonstrate that the rate of inner COPII coat recruitment serves as a determinant for the pace of cargo export, irrespective of COPII subunit expression levels. Moreover, increasing inner COPII coat recruitment kinetics is sufficient to rescue cargo trafficking deficits caused by acute nutrient limitation. Our findings are consistent with a model in which the rate of inner COPII coat addition acts as an important control point to regulate cargo export from the ER.
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Affiliation(s)
- William Kasberg
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706, USA
| | - Peter Luong
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706, USA
| | - Kevin A Swift
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706, USA
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706, USA.
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7
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Clay R, Siddiqi S, Siddiqi SA. α-Tocopherol reduces VLDL secretion through modulation of intracellular ER-to-Golgi transport of VLDL. Can J Physiol Pharmacol 2023; 101:554-564. [PMID: 37683292 PMCID: PMC11418172 DOI: 10.1139/cjpp-2023-0086] [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: 09/10/2023]
Abstract
Avoiding hepatic steatosis is crucial for preventing liver dysfunction, and one mechanism by which this is accomplished is through synchronization of the rate of very low density lipoprotein (VLDL) synthesis with its secretion. Endoplasmic reticulum (ER)-to-Golgi transport of nascent VLDL is the rate-limiting step in its secretion and is mediated by the VLDL transport vesicle (VTV). Recent in vivo studies have indicated that α-tocopherol (α-T) supplementation can reverse steatosis in nonalcoholic fatty liver disease, but its effects on hepatic lipoprotein metabolism are poorly understood. Here, we investigated the impact of α-T on hepatic VLDL synthesis, secretion, and intracellular ER-to-Golgi VLDL trafficking using an in vitro model. Pulse-chase assays using [3H]-oleic acid and 100 µmol/L α-T demonstrated a disruption of early VLDL synthesis, resulting in enhanced apolipoprotein B-100 expression, decreased expression in markers for VTV budding, ER-to-Golgi VLDL transport, and reduced VLDL secretion. Additionally, an in vitro VTV budding assay indicated a significant decrease in VTV production and VTV-Golgi fusion. Confocal imaging of lipid droplet (LD) localization revealed a decrease in overall LD retention, diminished presence of ER-associated LDs, and an increase in Golgi-level LD retention. We conclude that α-T disrupts ER-to-Golgi VLDL transport by modulating the expression of specific proteins and thus reduces VLDL secretion.
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Affiliation(s)
- Ryan Clay
- Division of Metabolic and Cardiovascular Sciences, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA
| | - Shaila Siddiqi
- Division of Metabolic and Cardiovascular Sciences, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA
| | - Shadab A Siddiqi
- Division of Metabolic and Cardiovascular Sciences, Burnett School of Biomedical Sciences, College of Medicine, University of Central Florida, Orlando, FL 32827, USA
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8
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Kasberg W, Luong P, Hanna MG, Minushkin K, Tsao A, Shankar R, Block S, Audhya A. The Sar1 GTPase is dispensable for COPII-dependent cargo export from the ER. Cell Rep 2023; 42:112635. [PMID: 37300835 PMCID: PMC10592460 DOI: 10.1016/j.celrep.2023.112635] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 04/21/2023] [Accepted: 05/25/2023] [Indexed: 06/12/2023] Open
Abstract
Coat protein complex II (COPII) plays an integral role in the packaging of secretory cargoes within membrane-enclosed transport carriers that leave the endoplasmic reticulum (ER) from discrete subdomains. Lipid bilayer remodeling necessary for this process is driven initially by membrane penetration mediated by the Sar1 GTPase and further stabilized by assembly of a multilayered complex of several COPII proteins. However, the relative contributions of these distinct factors to transport carrier formation and protein trafficking remain unclear. Here, we demonstrate that anterograde cargo transport from the ER continues in the absence of Sar1, although the efficiency of this process is dramatically reduced. Specifically, secretory cargoes are retained nearly five times longer at ER subdomains when Sar1 is depleted, but they ultimately remain capable of being translocated to the perinuclear region of cells. Taken together, our findings highlight alternative mechanisms by which COPII promotes transport carrier biogenesis.
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Affiliation(s)
- William Kasberg
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Peter Luong
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Michael G Hanna
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Kayla Minushkin
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Annabelle Tsao
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Raakhee Shankar
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Samuel Block
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53706, USA.
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9
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Liu S, Yang B, Hou Y, Cui K, Yang X, Li X, Chen L, Liu S, Zhang Z, Jia Y, Xie Y, Xue Y, Li X, Yan B, Wu C, Deng W, Qi J, Lu D, Gao GF, Wang P, Shang G. The mechanism of STING autoinhibition and activation. Mol Cell 2023; 83:1502-1518.e10. [PMID: 37086726 DOI: 10.1016/j.molcel.2023.03.029] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/21/2022] [Accepted: 03/30/2023] [Indexed: 04/24/2023]
Abstract
2',3'-cGAMP, produced by the DNA sensor cGAS, activates stimulator of interferon genes (STING) and triggers immune response during infection. Tremendous effort has been placed on unraveling the mechanism of STING activation. However, little is known about STING inhibition. Here, we found that apo-STING exhibits a bilayer with head-to-head as well as side-by-side packing, mediated by its ligand-binding domain (LBD). This type of assembly holds two endoplasmic reticulum (ER) membranes together not only to prevent STING ER exit but also to eliminate the recruitment of TBK1, representing the autoinhibited state of STING. Additionally, we obtained the filament structure of the STING/2',3'-cGAMP complex, which adopts a bent monolayer assembly mediated by LBD and transmembrane domain (TMD). The active, curved STING polymer could deform ER membrane to support its ER exit and anterograde transportation. Our data together provide a panoramic vision regarding STING autoinhibition and activation, which adds substantially to current understanding of the cGAS-STING pathway.
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Affiliation(s)
- Sheng Liu
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Cryo-EM Center, Southern University of Science and Technology, Shenzhen 518055, China
| | - Bo Yang
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; College of Life Sciences, Shanxi Agricultural University, Taiyuan 030031, China; Shanxi Provincial Key Laboratory for Major Infectious Disease Response, Taiyuan 030012, China
| | - Yingxiang Hou
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; The Key Laboratory of Medical Molecular Cell Biology of Shanxi Province, Institutes of Biomedical Sciences, Shanxi University, Taiyuan 030006, China
| | - Kaige Cui
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; Shanxi Provincial Key Laboratory for Major Infectious Disease Response, Taiyuan 030012, China
| | - Xiaozhu Yang
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; Shanxi Provincial Key Laboratory for Major Infectious Disease Response, Taiyuan 030012, China
| | - Xiaoxiong Li
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; Shanxi Provincial Key Laboratory for Major Infectious Disease Response, Taiyuan 030012, China
| | - Lianwan Chen
- National Key Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Shichao Liu
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; Shanxi Provincial Key Laboratory for Major Infectious Disease Response, Taiyuan 030012, China
| | - Zhichao Zhang
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; Shanxi Provincial Key Laboratory for Major Infectious Disease Response, Taiyuan 030012, China
| | - Yuanyuan Jia
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; Shanxi Provincial Key Laboratory for Major Infectious Disease Response, Taiyuan 030012, China
| | - Yufeng Xie
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Department of Basic Medical Sciences, School of Medicine, Tsinghua University, Beijing 100084, China
| | - Ying Xue
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; Shanxi Provincial Key Laboratory for Major Infectious Disease Response, Taiyuan 030012, China
| | - Xiaomei Li
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China
| | - Bingxue Yan
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China
| | - Changxin Wu
- The Key Laboratory of Medical Molecular Cell Biology of Shanxi Province, Institutes of Biomedical Sciences, Shanxi University, Taiyuan 030006, China
| | - Wen Deng
- College of Veterinary Medicine, Northwest A&F University, Yangling 712100, China
| | - Jianxun Qi
- CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; Beijing Life Science Academy, Beijing 102209, China
| | - Defen Lu
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; College of Life Sciences, Shanxi Agricultural University, Taiyuan 030031, China.
| | - George F Gao
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; CAS Key Laboratory of Pathogen Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
| | - Peiyi Wang
- Cryo-EM Center, Southern University of Science and Technology, Shenzhen 518055, China.
| | - Guijun Shang
- Shanxi Provincial Key Laboratory of Protein Structure Determination, Shanxi Academy of Advanced Research and Innovation, Taiyuan 030012, China; College of Life Sciences, Shanxi Agricultural University, Taiyuan 030031, China; Shanxi Provincial Key Laboratory for Major Infectious Disease Response, Taiyuan 030012, China.
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10
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Kasberg W, Luong P, Swift KA, Audhya A. Nutrient deprivation alters the rate of COPII coat assembly to tune secretory protein transport. RESEARCH SQUARE 2023:rs.3.rs-2652351. [PMID: 36993182 PMCID: PMC10055522 DOI: 10.21203/rs.3.rs-2652351/v1] [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: 06/19/2023]
Abstract
Co-assembly of the multilayered coat protein complex II (COPII) with the Sari GTPase at subdomains of the endoplasmic reticulum (ER) enables secretory cargoes to be concentrated efficiently within nascent transport intermediates, which subsequently deliver their contents to ER-Golgi intermediate compartments. Here, we define the spatiotemporal accumulation of native COPII subunits and secretory cargoes at ER subdomains under differing nutrient availability conditions using a combination of CRISPR/Cas9-mediated genome editing and live cell imaging. Our findings demonstrate that the rate of inner COPII coat assembly serves as a determinant for the pace of cargo export, irrespective of COPII subunit expression levels. Moreover, increasing inner COPII coat assembly kinetics is sufficient to rescue cargo trafficking deficits caused by acute nutrient limitation in a manner dependent on Sar1 GTPase activity. Our findings are consistent with a model in which the rate of inner COPII coat formation acts as an important control point to regulate cargo export from the ER.
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Affiliation(s)
- William Kasberg
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706, USA
| | - Peter Luong
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706, USA
| | - Kevin A. Swift
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706, USA
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI, 53706, USA
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11
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Bali K, Guffick C, McCoy R, Lu Z, Kaminski CF, Mela I, Owens RM, van Veen HW. Biosensor for Multimodal Characterization of an Essential ABC Transporter for Next-Generation Antibiotic Research. ACS APPLIED MATERIALS & INTERFACES 2023; 15:12766-12776. [PMID: 36866935 PMCID: PMC10020959 DOI: 10.1021/acsami.2c21556] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 02/15/2023] [Indexed: 05/21/2023]
Abstract
As the threat of antibiotic resistance increases, there is a particular focus on developing antimicrobials against pathogenic bacteria whose multidrug resistance is especially entrenched and concerning. One such target for novel antimicrobials is the ATP-binding cassette (ABC) transporter MsbA that is present in the plasma membrane of Gram-negative pathogenic bacteria where it is fundamental to the survival of these bacteria. Supported lipid bilayers (SLBs) are useful in monitoring membrane protein structure and function since they can be integrated with a variety of optical, biochemical, and electrochemical techniques. Here, we form SLBs containing Escherichia coli MsbA and use atomic force microscopy (AFM) and structured illumination microscopy (SIM) as high-resolution microscopy techniques to study the integrity of the SLBs and incorporated MsbA proteins. We then integrate these SLBs on microelectrode arrays (MEA) based on the conducting polymer poly(3,4-ethylenedioxy-thiophene) poly(styrene sulfonate) (PEDOT:PSS) using electrochemical impedance spectroscopy (EIS) to monitor ion flow through MsbA proteins in response to ATP hydrolysis. These EIS measurements can be correlated with the biochemical detection of MsbA-ATPase activity. To show the potential of this SLB approach, we observe not only the activity of wild-type MsbA but also the activity of two previously characterized mutants along with quinoline-based MsbA inhibitor G907 to show that EIS systems can detect changes in ABC transporter activity. Our work combines a multitude of techniques to thoroughly investigate MsbA in lipid bilayers as well as the effects of potential inhibitors of this protein. We envisage that this platform will facilitate the development of next-generation antimicrobials that inhibit MsbA or other essential membrane transporters in microorganisms.
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Affiliation(s)
- Karan Bali
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0AS Cambridge, U. K.
| | - Charlotte Guffick
- Department
of Pharmacology, University of Cambridge, CB2 1PD Cambridge, U. K.
| | - Reece McCoy
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0AS Cambridge, U. K.
| | - Zixuan Lu
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0AS Cambridge, U. K.
| | - Clemens F. Kaminski
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0AS Cambridge, U. K.
| | - Ioanna Mela
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0AS Cambridge, U. K.
| | - Róisín M. Owens
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0AS Cambridge, U. K.
| | - Hendrik W. van Veen
- Department
of Pharmacology, University of Cambridge, CB2 1PD Cambridge, U. K.
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12
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Paul S, Audhya A, Cui Q. Molecular mechanism of GTP binding- and dimerization-induced enhancement of Sar1-mediated membrane remodeling. Proc Natl Acad Sci U S A 2023; 120:e2212513120. [PMID: 36780528 PMCID: PMC9974494 DOI: 10.1073/pnas.2212513120] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 01/18/2023] [Indexed: 02/15/2023] Open
Abstract
The Sar1 GTPase initiates coat protein II (COPII)-mediated protein transport by generating membrane curvature at subdomains on the endoplasmic reticulum, where it is activated by the guanine nucleotide exchange factor (GEF) Sec12. Crystal structures of GDP- and GTP-bound forms of Sar1 suggest that it undergoes a conformational switch in which GTP binding enhances the exposure of an amino-terminal amphipathic helix necessary for efficient membrane penetration. However, key residues in the amino terminus were not resolved in crystal structures, and experimental studies have suggested that the amino terminus of Sar1 is solvent-exposed in the absence of a membrane, even in the GDP-bound state. Therefore, the molecular mechanism by which GTP binding activates the membrane-remodeling activity of Sar1 remains unclear. Using atomistic molecular dynamics simulations, we compare the membrane-binding and curvature generation activities of Sar1 in its GDP- and GTP-bound states. We show that in the GTP-bound state, Sar1 inserts into the membrane with its complete (residues 1 to 23) amphipathic amino-terminal helix, while Sar1-GDP binds to the membrane only through its first 12 residues. Such differential membrane-binding modes translate into significant differences in the protein volume inserted into the membrane. As a result, Sar1-GTP generates positive membrane curvature 10 to 20 times higher than Sar1-GDP. Dimerization of the GTP-bound form of Sar1 further amplifies curvature generation. Taken together, our results present a detailed molecular mechanism for how the nucleotide-bound state of Sar1 regulates its membrane-binding and remodeling activities in a concentration-dependent manner, paving the way toward a better understanding COPII-mediated membrane transport.
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Affiliation(s)
- Sanjoy Paul
- Department of Chemistry, Boston University, Boston, MA02215
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI53706
| | - Qiang Cui
- Department of Chemistry, Boston University, Boston, MA02215
- Departments of Physics, Boston University, Boston, MA02215
- Departments of Biomedical Engineering, Boston University, Boston, MA02215
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13
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Van der Verren SE, Zanetti G. The small GTPase Sar1, control centre of COPII trafficking. FEBS Lett 2023; 597:865-882. [PMID: 36737236 DOI: 10.1002/1873-3468.14595] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/23/2023] [Accepted: 01/25/2023] [Indexed: 02/05/2023]
Abstract
Sar1 is a small GTPase of the ARF family. Upon exchange of GDP for GTP, Sar1 associates with the endoplasmic reticulum (ER) membrane and recruits COPII components, orchestrating cargo concentration and membrane deformation. Many aspects of the role of Sar1 and regulation of its GTP cycle remain unclear, especially as complexity increases in higher organisms that secrete a wider range of cargoes. This review focusses on the regulation of GTP hydrolysis and its role in coat assembly, as well as the mechanism of Sar1-induced membrane deformation and scission. Finally, we highlight the additional specialisation in higher eukaryotes and the outstanding questions on how Sar1 functions are orchestrated.
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Affiliation(s)
| | - Giulia Zanetti
- Institute of Structural and Molecular Biology, Birkbeck College London, UK
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14
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Barrabi C, Zhang K, Liu M, Chen X. Pancreatic beta cell ER export in health and diabetes. Front Endocrinol (Lausanne) 2023; 14:1155779. [PMID: 37152949 PMCID: PMC10160654 DOI: 10.3389/fendo.2023.1155779] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 04/10/2023] [Indexed: 05/09/2023] Open
Abstract
In the secretory pathway of the pancreatic beta cell, proinsulin and other secretory granule proteins are first produced in the endoplasmic reticulum (ER). Beta cell ER homeostasis is vital for normal beta cell functions and is maintained by the delicate balance between protein synthesis, folding, export and degradation. Disruption of ER homeostasis leads to beta cell death and diabetes. Among the four components to maintain ER homeostasis, the role of ER export in insulin biogenesis or beta cell survival was not well-understood. COPII (coat protein complex II) dependent transport is a conserved mechanism for most cargo proteins to exit ER and transport to Golgi apparatus. Emerging evidence began to reveal a critical role of COPII-dependent ER export in beta cells. In this review, we will first discuss the basic components of the COPII transport machinery, the regulation of cargo entry and COPII coat assembly in mammalian cells, and the general concept of receptor-mediated cargo sorting in COPII vesicles. On the basis of these general discussions, the current knowledge and recent developments specific to the beta cell COPII dependent ER export are summarized under normal and diabetic conditions.
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Affiliation(s)
- Cesar Barrabi
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, United States
| | - Kezhong Zhang
- Center for Molecular Medicine and Genetics, School of Medicine, Wayne State University, Detroit, MI, United States
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Xuequn Chen
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI, United States
- *Correspondence: Xuequn Chen,
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15
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The Golgi-resident protein ACBD3 concentrates STING at ER-Golgi contact sites to drive export from the ER. Cell Rep 2022; 41:111868. [PMID: 36543137 DOI: 10.1016/j.celrep.2022.111868] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 10/27/2022] [Accepted: 11/30/2022] [Indexed: 12/24/2022] Open
Abstract
STING, an endoplasmic reticulum (ER)-resident receptor for cyclic di-nucleotides (CDNs), is essential for innate immune responses. Upon CDN binding, STING moves from the ER to the Golgi, where it activates downstream type-I interferon (IFN) signaling. General cargo proteins exit from the ER via concentration at ER exit sites. However, the mechanism of STING concentration is poorly understood. Here, we visualize the ER exit sites of STING by blocking its transport at low temperature or by live-cell imaging with the cell-permeable ligand bis-pivSATE-2'F-c-di-dAMP, which we have developed. After ligand binding, STING forms punctate foci at non-canonical ER exit sites. Unbiased proteomic screens and super-resolution microscopy show that the Golgi-resident protein ACBD3/GCP60 recognizes and concentrates ligand-bound STING at specialized ER-Golgi contact sites. Depletion of ACBD3 impairs STING ER-to-Golgi trafficking and type-I IFN responses. Our results identify the ACBD3-mediated non-canonical cargo concentration system that drives the ER exit of STING.
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16
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Clarke AL, Lettman MM, Audhya A. Lgd regulates ESCRT-III complex accumulation at multivesicular endosomes to control intralumenal vesicle formation. Mol Biol Cell 2022; 33:ar144. [PMID: 36287829 PMCID: PMC9727795 DOI: 10.1091/mbc.e22-08-0342] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/13/2022] [Accepted: 10/18/2022] [Indexed: 02/04/2023] Open
Abstract
Membrane remodeling mediated by heteropolymeric filaments composed of ESCRT-III subunits is an essential process that occurs at a variety of organelles to maintain cellular homeostasis. Members of the evolutionarily conserved Lgd/CC2D1 protein family have been suggested to regulate ESCRT-III polymer assembly, although their specific roles, particularly in vivo, remain unclear. Using the Caenorhabditis elegans early embryo as a model system, we show that Lgd/CC2D1 localizes to endosomal membranes, and its loss impairs endolysosomal cargo sorting and degradation. At the ultrastructural level, the absence of Lgd/CC2D1 results in the accumulation of enlarged endosomal compartments that contain a reduced number of intralumenal vesicles (ILVs). However, unlike aberrant endosome morphology caused by depletion of other ESCRT components, ILV size is only modestly altered in embryos lacking Lgd/CC2D1. Instead, loss of Lgd/CC2D1 impairs normal accumulation of ESCRT-III on endosomal membranes, likely slowing the kinetics of ILV formation. Together, our findings suggest a role for Lgd/CC2D1 in the recruitment and/or stable assembly of ESCRT-III subunits on endosomal membranes to facilitate efficient ILV biogenesis.
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Affiliation(s)
- Aryel L. Clarke
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Molly M. Lettman
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
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17
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Melero A, Boulanger J, Kukulski W, Miller EA. Ultrastructure of COPII vesicle formation in yeast characterized by correlative light and electron microscopy. Mol Biol Cell 2022; 33:ar122. [PMID: 36001360 PMCID: PMC9634970 DOI: 10.1091/mbc.e22-03-0103] [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] [Indexed: 01/18/2023] Open
Abstract
Traffic of proteins out of the endoplasmic reticulum (ER) is driven by the COPII coat, a layered protein scaffold that mediates the capture of cargo proteins and the remodeling of the ER membrane into spherical vesicular carriers. Although the components of this machinery have been genetically defined, and the mechanisms of coat assembly extensively explored in vitro, understanding the physical mechanisms of membrane remodeling in cells remains a challenge. Here we use correlative light and electron microscopy (CLEM) to visualize the nanoscale ultrastructure of membrane remodeling at ER exit sites (ERES) in yeast cells. Using various COPII mutants, we have determined the broad contribution that each layer of the coat makes to membrane remodeling. Our data suggest that inner coat components define the radius of curvature, whereas outer coat components facilitate membrane fission. The organization of the coat in conjunction with membrane biophysical properties determines the ultrastructure of vesicles and thus the efficiency of protein transport.
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Affiliation(s)
- Alejandro Melero
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
- *Address correspondence to: Elizabeth A. Miller (); Alejandro Melero ()
| | - Jerome Boulanger
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Wanda Kukulski
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
| | - Elizabeth A. Miller
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge CB2 0QH, United Kingdom
- *Address correspondence to: Elizabeth A. Miller (); Alejandro Melero ()
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18
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Pathway engineering facilitates efficient protein expression in Pichia pastoris. Appl Microbiol Biotechnol 2022; 106:5893-5912. [PMID: 36040488 DOI: 10.1007/s00253-022-12139-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 11/02/2022]
Abstract
Pichia pastoris has been recognized as an important platform for the production of various heterologous proteins in recent years. The strong promoter AOX1, induced by methanol, with the help of the α-pre-pro signal sequence, can lead to a high expression level of extracellular protein. However, this combination was not always efficient, as protein secretion in P. pastoris involves numerous procedures mediated by several cellular proteins, including folding assisted by endoplasmic reticulum (ER) molecular chaperones, degradation through ubiquitination, and an efficient vesicular transport system. Efficient protein expression requires the cooperation of various intracellular pathways. This article summarizes the process of protein secretion, modification, and transportation in P. pastoris. In addition, the roles played by the key proteins in these processes and the corresponding co-expression effects are also listed. It is expected to lay the foundation for the industrial protein production of P. pastoris. KEY POINTS: • Mechanisms of chaperones in protein folding and their co-expression effects are summarized. • Protein glycosylation modifications are comprehensively reviewed. • Current dilemmas in the overall protein secretion pathway of Pichia pastoris and corresponding solutions are demonstrated.
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19
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Malis Y, Hirschberg K, Kaether C. Hanging the coat on a collar: Same function but different localization and mechanism for COPII. Bioessays 2022; 44:e2200064. [DOI: 10.1002/bies.202200064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 11/09/2022]
Affiliation(s)
- Yehonathan Malis
- Department of Pathology, Sackler School of Medicine Tel‐Aviv University Tel Aviv Israel
| | - Koret Hirschberg
- Department of Pathology, Sackler School of Medicine Tel‐Aviv University Tel Aviv Israel
| | - Christoph Kaether
- Leibniz Institute for Age Research – Fritz Lipmann Institute Jena Germany
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20
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Bali K, Mohamed Z, Scheeder A, Pappa AM, Daniel S, Kaminski CF, Owens RM, Mela I. Nanoscale Features of Tunable Bacterial Outer Membrane Models Revealed by Correlative Microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:8773-8782. [PMID: 35748045 PMCID: PMC9330759 DOI: 10.1021/acs.langmuir.2c00628] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The rise of antibiotic resistance is a growing worldwide human health issue, with major socioeconomic implications. An understanding of the interactions occurring at the bacterial membrane is crucial for the generation of new antibiotics. Supported lipid bilayers (SLBs) made from reconstituted lipid vesicles have been used to mimic these membranes, but their utility has been restricted by the simplistic nature of these systems. A breakthrough in the field has come with the use of outer membrane vesicles derived from Gram-negative bacteria to form SLBs, thus providing a more physiologically relevant system. These complex bilayer systems hold promise but have not yet been fully characterized in terms of their composition, ratio of natural to synthetic components, and membrane protein content. Here, we use correlative atomic force microscopy (AFM) with structured illumination microscopy (SIM) for the accurate mapping of complex lipid bilayers that consist of a synthetic fraction and a fraction of lipids derived from Escherichia coli outer membrane vesicles (OMVs). We exploit the high resolution and molecular specificity that SIM can offer to identify areas of interest in these bilayers and the enhanced resolution that AFM provides to create detailed topography maps of the bilayers. We are thus able to understand the way in which the two different lipid fractions (natural and synthetic) mix within the bilayers, and we can quantify the amount of bacterial membrane incorporated into the bilayer. We prove the system's tunability by generating bilayers made using OMVs engineered to contain a green fluorescent protein (GFP) binding nanobody fused with the porin OmpA. We are able to directly visualize protein-protein interactions between GFP and the nanobody complex. Our work sets the foundation for accurately understanding the composition and properties of OMV-derived SLBs to generate a high-resolution platform for investigating bacterial membrane interactions for the development of next-generation antibiotics.
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Affiliation(s)
- Karan Bali
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, U.K.
| | - Zeinab Mohamed
- School
of Biomedical Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Anna Scheeder
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, U.K.
| | - Anna-Maria Pappa
- Department
of Biomedical Engineering, Khalifa University
of Science and Technology, Abu
Dhabi 127788, United Arab
Emirates
| | - Susan Daniel
- School
of Biomedical Engineering, Cornell University, Ithaca, New York 14853, United States
- School
of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States
| | - Clemens F. Kaminski
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, U.K.
| | - Róisín M. Owens
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, U.K.
| | - Ioanna Mela
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, Cambridge CB3 0AS, U.K.
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21
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Circularized fluorescent nanodiscs for probing protein-lipid interactions. Commun Biol 2022; 5:507. [PMID: 35618817 PMCID: PMC9135701 DOI: 10.1038/s42003-022-03443-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 05/03/2022] [Indexed: 12/29/2022] Open
Abstract
Protein–lipid interactions are vital for numerous transmembrane signaling pathways. However, simple tools to characterize these interactions remain scarce and are much needed to advance our understanding of signal transduction across lipid bilayers. To tackle this challenge, we herein engineer nanodisc as a robust fluorescent sensor for reporting membrane biochemical reactions. We circularize nanodiscs via split GFP and thereby create an intensity-based fluorescent sensor (isenND) for detecting membrane binding and remodeling events. We show that isenND responds robustly and specifically to the action of a diverse array of membrane-interacting proteins and peptides, ranging from synaptotagmin and synuclein involved in neurotransmission to viral fusion peptides of HIV-1 and SARS-CoV-2. Together, isenND can serve as a versatile biochemical reagent useful for basic and translational research of membrane biology. A fluorescent probe for detecting membrane protein binding and remodeling events is presented, which relies on split-GFP technology to generate circularized nanodiscs useful in membrane protein biophysics and structural biology.
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22
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Vozdek R, Pramstaller PP, Hicks AA. Functional Screening of Parkinson's Disease Susceptibility Genes to Identify Novel Modulators of α-Synuclein Neurotoxicity in Caenorhabditis elegans. Front Aging Neurosci 2022; 14:806000. [PMID: 35572147 PMCID: PMC9093606 DOI: 10.3389/fnagi.2022.806000] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 03/18/2022] [Indexed: 11/24/2022] Open
Abstract
Idiopathic Parkinson's disease (PD) is characterized by progressive loss of dopaminergic (DA) neurons during aging. The pathological hallmark of PD is the Lewy body detected in postmortem brain tissue, which is mainly composed of aggregated α-Synuclein (αSyn). However, it is estimated that 90% of PD cases have unknown pathogenetic triggers. Here, we generated a new transgenic Caenorhabditis elegans PD model eraIs1 expressing green fluorescent protein- (GFP-) based reporter of human αSyn in DA neurons, and exhibited a nice readout of the developed αSyn inclusions in DA neurons, leading to their degeneration during aging. Using these animals in a preliminary reverse genetic screening of >100-PD genome-wide association study- (GWAS-) based susceptibility genes, we identified 28 orthologs of C. elegans and their inactivation altered the phenotype of eraIs1; 10 knockdowns exhibited reduced penetrance of αSyn:Venus inclusions formed in the axons of cephalic (CEP) DA neurons, 18 knockdowns exhibited increased penetrance of disrupted CEP dendrite integrity among which nine knockdowns also exhibited disrupted neuronal morphology independent of the expressed αSyn reporter. Loss-of-function alleles of the five identified genes, such as sac-2, rig-6 or lfe-2, unc-43, and nsf-1, modulated the corresponding eraIs1 phenotype, respectively, and supported the RNA interference (RNAi) data. The Western blot analysis showed that the levels of insoluble αSyn:Venus were not correlated with the observed phenotypes in these mutants. However, RNAi of 12 identified modulators reduced the formation of pro-aggregating polyglutamine Q40:YFP foci in muscle cells, suggesting the possible role of these genes in cellular proteotoxicity. Therefore, modulators identified by their associated biological pathways, such as calcium signaling or vesicular trafficking, represent new potential therapeutic targets for neurodegenerative proteopathies and other diseases associated with aging.
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Affiliation(s)
- Roman Vozdek
- Institute for Biomedicine, Eurac Research, Affiliated Institute of the University of Lübeck, Bolzano, Italy
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23
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A tango for coats and membranes: New insights into ER-to-Golgi traffic. Cell Rep 2022; 38:110258. [DOI: 10.1016/j.celrep.2021.110258] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 11/17/2021] [Accepted: 12/21/2021] [Indexed: 12/30/2022] Open
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24
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Utility of Bioluminescent Homogeneous Nucleotide Detection Assays in Measuring Activities of Nucleotide-Sugar Dependent Glycosyltransferases and Studying Their Inhibitors. Molecules 2021; 26:molecules26206230. [PMID: 34684811 PMCID: PMC8539010 DOI: 10.3390/molecules26206230] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 10/11/2021] [Accepted: 10/12/2021] [Indexed: 01/22/2023] Open
Abstract
Traditional glycosyltransferase (GT) activity assays are not easily configured for rapid detection nor for high throughput screening because they rely on radioactive product isolation, the use of heterogeneous immunoassays or mass spectrometry. In a typical glycosyltransferase biochemical reaction, two products are generated, a glycosylated product and a nucleotide released from the sugar donor substrate. Therefore, an assay that detects the nucleotide could be universal to monitor the activity of diverse glycosyltransferases in vitro. Here we describe three homogeneous and bioluminescent glycosyltransferase activity assays based on UDP, GDP, CMP, and UMP detection. Each of these assays are performed in a one-step detection that relies on converting the nucleotide product to ATP, then to bioluminescence using firefly luciferase. These assays are highly sensitive, robust and resistant to chemical interference. Various applications of these assays are presented, including studies on the specificity of sugar transfer by diverse GTs and the characterization of acceptor substrate-dependent and independent nucleotide-sugar hydrolysis. Furthermore, their utility in screening for specific GT inhibitors and the study of their mode of action are described. We believe that the broad utility of these nucleotide assays will enable the investigation of a large number of GTs and may have a significant impact on diverse areas of Glycobiology research.
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25
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Jalal ASB, Tran NT, Wu LJ, Ramakrishnan K, Rejzek M, Gobbato G, Stevenson CEM, Lawson DM, Errington J, Le TBK. CTP regulates membrane-binding activity of the nucleoid occlusion protein Noc. Mol Cell 2021; 81:3623-3636.e6. [PMID: 34270916 DOI: 10.1101/2021.02.11.430593] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 05/25/2021] [Accepted: 06/18/2021] [Indexed: 05/25/2023]
Abstract
ATP- and GTP-dependent molecular switches are extensively used to control functions of proteins in a wide range of biological processes. However, CTP switches are rarely reported. Here, we report that a nucleoid occlusion protein Noc is a CTPase enzyme whose membrane-binding activity is directly regulated by a CTP switch. In Bacillus subtilis, Noc nucleates on 16 bp NBS sites before associating with neighboring non-specific DNA to form large membrane-associated nucleoprotein complexes to physically occlude assembly of the cell division machinery. By in vitro reconstitution, we show that (1) CTP is required for Noc to form the NBS-dependent nucleoprotein complex, and (2) CTP binding, but not hydrolysis, switches Noc to a membrane-active state. Overall, we suggest that CTP couples membrane-binding activity of Noc to nucleoprotein complex formation to ensure productive recruitment of DNA to the bacterial cell membrane for nucleoid occlusion activity.
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Affiliation(s)
- Adam S B Jalal
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK
| | - Ngat T Tran
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK
| | - Ling J Wu
- Centre for Bacterial Cell Biology, Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4AX, UK
| | | | - Martin Rejzek
- Chemistry Platform, John Innes Centre, Norwich, NR4 7UH, UK
| | - Giulia Gobbato
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK
| | | | - David M Lawson
- Department of Biological Chemistry, John Innes Centre, Norwich, NR4 7UH, UK
| | - Jeff Errington
- Centre for Bacterial Cell Biology, Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4AX, UK
| | - Tung B K Le
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK.
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26
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Recent developments in membrane curvature sensing and induction by proteins. Biochim Biophys Acta Gen Subj 2021; 1865:129971. [PMID: 34333084 DOI: 10.1016/j.bbagen.2021.129971] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 07/11/2021] [Accepted: 07/25/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND Membrane-bound intracellular organelles have characteristic shapes attributed to different local membrane curvatures, and these attributes are conserved across species. Over the past decade, it has been confirmed that specific proteins control the large curvatures of the membrane, whereas many others due to their specific structural features can sense the curvatures and bind to the specific geometrical cues. Elucidating the interplay between sensing and induction is indispensable to understand the mechanisms behind various biological processes such as vesicular trafficking and budding. SCOPE OF REVIEW We provide an overview of major classes of membrane proteins and the mechanisms of curvature sensing and induction. We then discuss the importance of membrane elastic characteristics to induce the membrane shapes similar to intracellular organelles. Finally, we survey recently available assays developed for studying the curvature sensing and induction by many proteins. MAJOR CONCLUSIONS Recent theoretical/computational modeling along with experimental studies have uncovered fascinating connections between lipid membrane and protein interactions. However, the phenomena of protein localization and synchronization to generate spatiotemporal dynamics in membrane morphology are yet to be fully understood. GENERAL SIGNIFICANCE The understanding of protein-membrane interactions is essential to shed light on various biological processes. This further enables the technological applications of many natural proteins/peptides in therapeutic treatments. The studies of membrane dynamic shapes help to understand the fundamental functions of membranes, while the medicinal roles of various macromolecules (such as proteins, peptides, etc.) are being increasingly investigated.
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27
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Jalal ASB, Tran NT, Wu LJ, Ramakrishnan K, Rejzek M, Gobbato G, Stevenson CEM, Lawson DM, Errington J, Le TBK. CTP regulates membrane-binding activity of the nucleoid occlusion protein Noc. Mol Cell 2021; 81:3623-3636.e6. [PMID: 34270916 PMCID: PMC8429893 DOI: 10.1016/j.molcel.2021.06.025] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 05/25/2021] [Accepted: 06/18/2021] [Indexed: 02/06/2023]
Abstract
ATP- and GTP-dependent molecular switches are extensively used to control functions of proteins in a wide range of biological processes. However, CTP switches are rarely reported. Here, we report that a nucleoid occlusion protein Noc is a CTPase enzyme whose membrane-binding activity is directly regulated by a CTP switch. In Bacillus subtilis, Noc nucleates on 16 bp NBS sites before associating with neighboring non-specific DNA to form large membrane-associated nucleoprotein complexes to physically occlude assembly of the cell division machinery. By in vitro reconstitution, we show that (1) CTP is required for Noc to form the NBS-dependent nucleoprotein complex, and (2) CTP binding, but not hydrolysis, switches Noc to a membrane-active state. Overall, we suggest that CTP couples membrane-binding activity of Noc to nucleoprotein complex formation to ensure productive recruitment of DNA to the bacterial cell membrane for nucleoid occlusion activity. CTP is required for Noc to form a higher-order nucleoprotein complex on DNA CTP binding switches DNA-entrapped Noc to a membrane-active state CTP hydrolysis likely reverses the association between Noc-DNA and the membrane The membrane-targeting helix adopts an autoinhibitory conformation in apo-Noc
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Affiliation(s)
- Adam S B Jalal
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK
| | - Ngat T Tran
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK
| | - Ling J Wu
- Centre for Bacterial Cell Biology, Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4AX, UK
| | | | - Martin Rejzek
- Chemistry Platform, John Innes Centre, Norwich, NR4 7UH, UK
| | - Giulia Gobbato
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK
| | | | - David M Lawson
- Department of Biological Chemistry, John Innes Centre, Norwich, NR4 7UH, UK
| | - Jeff Errington
- Centre for Bacterial Cell Biology, Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, NE2 4AX, UK
| | - Tung B K Le
- Department of Molecular Microbiology, John Innes Centre, Norwich, NR4 7UH, UK.
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Weigel AV, Chang CL, Shtengel G, Xu CS, Hoffman DP, Freeman M, Iyer N, Aaron J, Khuon S, Bogovic J, Qiu W, Hess HF, Lippincott-Schwartz J. ER-to-Golgi protein delivery through an interwoven, tubular network extending from ER. Cell 2021; 184:2412-2429.e16. [PMID: 33852913 DOI: 10.1016/j.cell.2021.03.035] [Citation(s) in RCA: 124] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 12/23/2020] [Accepted: 03/16/2021] [Indexed: 12/15/2022]
Abstract
Cellular versatility depends on accurate trafficking of diverse proteins to their organellar destinations. For the secretory pathway (followed by approximately 30% of all proteins), the physical nature of the vessel conducting the first portage (endoplasmic reticulum [ER] to Golgi apparatus) is unclear. We provide a dynamic 3D view of early secretory compartments in mammalian cells with isotropic resolution and precise protein localization using whole-cell, focused ion beam scanning electron microscopy with cryo-structured illumination microscopy and live-cell synchronized cargo release approaches. Rather than vesicles alone, the ER spawns an elaborate, interwoven tubular network of contiguous lipid bilayers (ER exit site) for protein export. This receptacle is capable of extending microns along microtubules while still connected to the ER by a thin neck. COPII localizes to this neck region and dynamically regulates cargo entry from the ER, while COPI acts more distally, escorting the detached, accelerating tubular entity on its way to joining the Golgi apparatus through microtubule-directed movement.
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Affiliation(s)
- Aubrey V Weigel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Chi-Lun Chang
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Gleb Shtengel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - C Shan Xu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | | | - Melanie Freeman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA; Advanced Bioimaging Center, Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Nirmala Iyer
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Jesse Aaron
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Satya Khuon
- Advanced Imaging Center, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - John Bogovic
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Wei Qiu
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Harald F Hess
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
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29
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Liu D, Zhang X, Liu X, Zhang A, Zhu B. Roles of a small GTPase Sar1 in ecdysteroid signaling and immune response of red swamp crayfish Procambarus clarkii. Int J Biol Macromol 2020; 166:550-556. [PMID: 33137382 DOI: 10.1016/j.ijbiomac.2020.10.212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/26/2020] [Accepted: 10/26/2020] [Indexed: 10/23/2022]
Abstract
Secretion-associated and ras-related protein 1 (Sar1) is a small GTPase that plays an important role in the transport of protein coated with coat protein complex II vesicles. However, its alternative roles in the biological processes of Procambarus clarkii remain unclear. Here, a sar1 gene (named as Pc-sar1) with an open reading frame of 582 bp from P. clarkii was identified. Pc-sar1 was expressed in all examined tissues with highest expression levels in muscle, which was determined by real-time PCR and western blotting. After the induction of lipopolysaccharide (LPS) and polycytidylic acid (Poly I: C), the transcriptional levels of Pc-sar1 differed in hepatopancreas, gill, muscle and intestine. In contrast, the expression of Pc-sar1 was upregulated by 20-hydroxyecdysone in these four tissues. In addition, the RNA interference of Pc-sar1 significantly affected the expression levels of immune and hormone-related genes. These results indicate that Pc-sar1 is involved in the innate immune response and ecdysteroid signaling pathway.
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Affiliation(s)
- Die Liu
- College of Life Sciences, Anhui Agricultural University, Hefei 230036, China
| | - Xiaojiao Zhang
- College of Life Sciences, Anhui Agricultural University, Hefei 230036, China
| | - Xiaoxiao Liu
- College of Life Sciences, Anhui Agricultural University, Hefei 230036, China
| | - Awei Zhang
- College of Life Sciences, Anhui Agricultural University, Hefei 230036, China
| | - Baojian Zhu
- College of Life Sciences, Anhui Agricultural University, Hefei 230036, China.
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30
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Abstract
STING is essential for control of infections and for tumor immunosurveillance, but can also drive pathological inflammation. STING resides on the endoplasmic reticulum (ER), and traffics following stimulation to ERGIC/Golgi where signaling occurs. Although STING ER exit is the rate-limiting step in STING signaling, the mechanism that drives this process is not understood. Here we identify STEEP as a positive regulator of STING signaling. STEEP was associated with STING and promoted trafficking from the ER. This was mediated through stimulation of phosphatidylinositol-3-phosphate (PI3P) production and ER membrane curvature formation, thus inducing COPII-mediated ER-to-Golgi trafficking of STING. Depletion of STEEP impaired STING-driven gene expression in response to virus infection in brain tissue and in cells from patients with STING-associated diseases. Interestingly, STING gain-of-function mutants from patients interacted strongly with STEEP leading to increased ER PI3P levels and membrane curvature. Thus, STEEP enables STING signaling by promoting ER exit.
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31
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Melville DB, Studer S, Schekman R. Small sequence variations between two mammalian paralogs of the small GTPase SAR1 underlie functional differences in coat protein complex II assembly. J Biol Chem 2020; 295:8401-8412. [PMID: 32358066 PMCID: PMC7307210 DOI: 10.1074/jbc.ra120.012964] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/27/2020] [Indexed: 01/03/2023] Open
Abstract
Vesicles that are coated by coat protein complex II (COPII) are the primary mediators of vesicular traffic from the endoplasmic reticulum to the Golgi apparatus. Secretion-associated Ras-related GTPase 1 (SAR1) is a small GTPase that is part of COPII and, upon GTP binding, recruits the other COPII proteins to the endoplasmic reticulum membrane. Mammals have two SAR1 paralogs that genetic data suggest may have distinct physiological roles, e.g. in lipoprotein secretion in the case of SAR1B. Here we identified two amino acid clusters that have conserved SAR1 paralog–specific sequences. We observed that one cluster is adjacent to the SAR1 GTP-binding pocket and alters the kinetics of GTP exchange. The other cluster is adjacent to the binding site for two COPII components, SEC31 homolog A COPII coat complex component (SEC31) and SEC23. We found that the latter cluster confers to SAR1B a binding preference for SEC23A that is stronger than that of SAR1A for SEC23A. Unlike SAR1B, SAR1A was prone to oligomerize on a membrane surface. SAR1B knockdown caused loss of lipoprotein secretion, overexpression of SAR1B but not of SAR1A could restore secretion, and a divergent cluster adjacent to the SEC31/SEC23-binding site was critical for this SAR1B function. These results highlight that small primary sequence differences between the two mammalian SAR1 paralogs lead to pronounced biochemical differences that significantly affect COPII assembly and identify a specific function for SAR1B in lipoprotein secretion, providing insights into the mechanisms of large cargo secretion that may be relevant for COPII-related diseases.
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Affiliation(s)
- David B Melville
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, California, USA
| | - Sean Studer
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, California, USA
| | - Randy Schekman
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, California, USA
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32
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Zhukovsky MA, Filograna A, Luini A, Corda D, Valente C. Protein Amphipathic Helix Insertion: A Mechanism to Induce Membrane Fission. Front Cell Dev Biol 2019; 7:291. [PMID: 31921835 PMCID: PMC6914677 DOI: 10.3389/fcell.2019.00291] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 11/06/2019] [Indexed: 12/19/2022] Open
Abstract
One of the fundamental features of biomembranes is the ability to fuse or to separate. These processes called respectively membrane fusion and fission are central in the homeostasis of events such as those related to intracellular membrane traffic. Proteins that contain amphipathic helices (AHs) were suggested to mediate membrane fission via shallow insertion of these helices into the lipid bilayer. Here we analyze the AH-containing proteins that have been identified as essential for membrane fission and categorize them in few subfamilies, including small GTPases, Atg proteins, and proteins containing either the ENTH/ANTH- or the BAR-domain. AH-containing fission-inducing proteins may require cofactors such as additional proteins (e.g., lipid-modifying enzymes), or lipids (e.g., phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2], phosphatidic acid [PA], or cardiolipin). Both PA and cardiolipin possess a cone shape and a negative charge (-2) that favor the recruitment of the AHs of fission-inducing proteins. Instead, PtdIns(4,5)P2 is characterized by an high negative charge able to recruit basic residues of the AHs of fission-inducing proteins. Here we propose that the AHs of fission-inducing proteins contain sequence motifs that bind lipid cofactors; accordingly (K/R/H)(K/R/H)xx(K/R/H) is a PtdIns(4,5)P2-binding motif, (K/R)x6(F/Y) is a cardiolipin-binding motif, whereas KxK is a PA-binding motif. Following our analysis, we show that the AHs of many fission-inducing proteins possess five properties: (a) at least three basic residues on the hydrophilic side, (b) ability to oligomerize, (c) optimal (shallow) depth of insertion into the membrane, (d) positive cooperativity in membrane curvature generation, and (e) specific interaction with one of the lipids mentioned above. These lipid cofactors favor correct conformation, oligomeric state and optimal insertion depth. The most abundant lipid in a given organelle possessing high negative charge (more negative than -1) is usually the lipid cofactor in the fission event. Interestingly, naturally occurring mutations have been reported in AH-containing fission-inducing proteins and related to diseases such as centronuclear myopathy (amphiphysin 2), Charcot-Marie-Tooth disease (GDAP1), Parkinson's disease (α-synuclein). These findings add to the interest of the membrane fission process whose complete understanding will be instrumental for the elucidation of the pathogenesis of diseases involving mutations in the protein AHs.
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Affiliation(s)
- Mikhail A. Zhukovsky
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | | | | | - Daniela Corda
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
| | - Carmen Valente
- Institute of Biochemistry and Cell Biology, National Research Council, Naples, Italy
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33
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Bouvier B. Curvature as a Collective Coordinate in Enhanced Sampling Membrane Simulations. J Chem Theory Comput 2019; 15:6551-6561. [DOI: 10.1021/acs.jctc.9b00716] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Benjamin Bouvier
- Laboratoire de Glycochimie, des Antimicrobiens et des Agroressources, CNRS UMR7378/Université de Picardie Jules Verne, 10, rue Baudelocque, 80039 Amiens Cedex, France
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34
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Belessiotis-Richards A, Higgins SG, Butterworth B, Stevens MM, Alexander-Katz A. Single-Nanometer Changes in Nanopore Geometry Influence Curvature, Local Properties, and Protein Localization in Membrane Simulations. NANO LETTERS 2019; 19:4770-4778. [PMID: 31241342 DOI: 10.1021/acs.nanolett.9b01990] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Nanoporous surfaces are used in many applications in intracellular sensing and drug delivery. However, the effects of such nanostructures on cell membrane properties are still far from understood. Here, we use coarse-grained molecular dynamics simulations to show that nanoporous substrates can stimulate membrane-curvature effects and that this curvature-sensing effect is much more sensitive than previously thought. We define a series of design parameters for inducing a nanoscale membrane curvature and show that nanopore taper plays a key role in membrane deformation, elucidating a previously unexplored fabrication parameter applicable to many nanostructured biomaterials. We report significant changes in the membrane area per lipid and thickness at regions of curvature. Finally, we demonstrate that regions of the nanopore-induced membrane curvature act as local hotspots for an increased bioactivity. We show spontaneous binding and localization of the epsin N-terminal homology (ENTH) domain to the regions of curvature. Understanding this interplay between the membrane curvature and nanoporosity at the biointerface helps both explain recent biological results and suggests a pathway for developing the next generation of cell-active substrates.
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Affiliation(s)
- Alexis Belessiotis-Richards
- Department of Materials , Imperial College London , Exhibition Road , London SW7 2AZ , United Kingdom
- Department of Bioengineering , Imperial College London , Exhibition Road , London SW7 2AZ , United Kingdom
- Institute of Biomedical Engineering , Imperial College London , Exhibition Road , London SW7 2AZ , United Kingdom
| | - Stuart G Higgins
- Department of Materials , Imperial College London , Exhibition Road , London SW7 2AZ , United Kingdom
- Department of Bioengineering , Imperial College London , Exhibition Road , London SW7 2AZ , United Kingdom
- Institute of Biomedical Engineering , Imperial College London , Exhibition Road , London SW7 2AZ , United Kingdom
| | - Ben Butterworth
- Department of Materials , Imperial College London , Exhibition Road , London SW7 2AZ , United Kingdom
| | - Molly M Stevens
- Department of Materials , Imperial College London , Exhibition Road , London SW7 2AZ , United Kingdom
- Department of Bioengineering , Imperial College London , Exhibition Road , London SW7 2AZ , United Kingdom
- Institute of Biomedical Engineering , Imperial College London , Exhibition Road , London SW7 2AZ , United Kingdom
| | - Alfredo Alexander-Katz
- Department of Materials Science & Engineering , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
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35
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Peotter J, Kasberg W, Pustova I, Audhya A. COPII-mediated trafficking at the ER/ERGIC interface. Traffic 2019; 20:491-503. [PMID: 31059169 PMCID: PMC6640837 DOI: 10.1111/tra.12654] [Citation(s) in RCA: 89] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/25/2019] [Accepted: 05/02/2019] [Indexed: 12/16/2022]
Abstract
Coat proteins play multiple roles in the life cycle of a membrane-bound transport intermediate, functioning in lipid bilayer remodeling, cargo selection and targeting to an acceptor compartment. The Coat Protein complex II (COPII) coat is known to act in each of these capacities, but recent work highlights the necessity for numerous accessory factors at all stages of transport carrier existence. Here, we review recent findings that highlight the roles of COPII and its regulators in the biogenesis of tubular COPII-coated carriers in mammalian cells that enable cargo transport between the endoplasmic reticulum and ER-Golgi intermediate compartments, the first step in a series of trafficking events that ultimately allows for the distribution of biosynthetic secretory cargoes throughout the entire endomembrane system.
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Affiliation(s)
- Jennifer Peotter
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - William Kasberg
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Iryna Pustova
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, Wisconsin
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36
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Kurokawa K, Nakano A. The ER exit sites are specialized ER zones for the transport of cargo proteins from the ER to the Golgi apparatus. J Biochem 2019; 165:109-114. [PMID: 30304445 DOI: 10.1093/jb/mvy080] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 10/05/2018] [Indexed: 12/29/2022] Open
Abstract
The endoplasmic reticulum (ER) is a multifunctional organelle, including secretory protein biogenesis, lipid synthesis, drug metabolism, Ca2+ signalling and so on. Since the ER is a single continuous membrane structure, it includes distinct zones responsible for its different functions. The export of newly synthesized proteins from the ER is facilitated via coat protein complex II (COPII)-coated vesicles, which form in specialized zones within the ER, called the ER exit sites (ERES) or transitional ER. In this review, we highlight recent advances in our understanding of the structural organization of ERES, the correlation between the ERES and Golgi organization, and the faithful cargo transport mechanism from the ERES to the Golgi.
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Affiliation(s)
- Kazuo Kurokawa
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Akihiko Nakano
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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37
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Kibria KMK, Ferdous J, Sardar R, Panda A, Gupta D, Mohmmed A, Malhotra P. A genome-wide analysis of coatomer protein (COP) subunits of apicomplexan parasites and their evolutionary relationships. BMC Genomics 2019; 20:98. [PMID: 30704415 PMCID: PMC6357402 DOI: 10.1186/s12864-019-5463-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 01/17/2019] [Indexed: 02/08/2023] Open
Abstract
Background Protein secretion is an essential process in all eukaryotes including organisms belonging to the phylum Apicomplexa, which includes many intracellular parasites. The apicomplexan parasites possess a specialized collection of secretory organelles that release a number of proteins to facilitate the invasion of host cells and some of these proteins also participate in immune evasion. Like in other eukaryotes, these parasites possess a series of membrane-bound compartments, namely the endoplasmic reticulum (ER), the intermediate compartments (IC) or vesicular tubular clusters (VTS) and Golgi complex through which proteins pass in a sequential and vectorial fashion. Two sets of proteins; COPI and COPII are important for directing the sequential transfer of material between the ER and Golgi complex. Results Here, using in silico approaches, we identify the components of COPI and COPII complexes in the genome of apicomplexan organisms. The results showed that the COPI and COPII protein complexes are conserved in most apicomplexan genomes with few exceptions. Diversity among the components of COPI and COPII complexes in apicomplexan is either due to the absence of a subunit or due to the difference in the number of protein domains. For example, the COPI epsilon subunit and COPII sec13 subunit is absent in Babesia bovis, Theileria parva, and Theileria annulata genomes. Phylogenetic and domain analyses for all the proteins of COPI and COPII complexes was performed to predict their evolutionary relationship and functional significance. Conclusions The study thus provides insights into the apicomplexan COPI and COPII coating machinery, which is crucial for parasites secretory network needed for the invasion of host cells. Electronic supplementary material The online version of this article (10.1186/s12864-019-5463-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- K M Kaderi Kibria
- Department of Biotechnology and Genetic Engineering, Mawlana Bhashani Science and Technology University, Santosh, Tangail, 1902, Bangladesh.
| | - Jannatul Ferdous
- Department of Biotechnology and Genetic Engineering, Mawlana Bhashani Science and Technology University, Santosh, Tangail, 1902, Bangladesh
| | - Rahila Sardar
- Translational Bioinformatics Group, International Centre for Genetic Engineering and Biotechnology, P. O. Box 10504, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Ashutosh Panda
- Department of Microbiology, All India Institute of Medical Science, New Delhi, 29, India
| | - Dinesh Gupta
- Translational Bioinformatics Group, International Centre for Genetic Engineering and Biotechnology, P. O. Box 10504, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Asif Mohmmed
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, P. O. Box 10504, Aruna Asaf Ali Marg, New Delhi, 110067, India
| | - Pawan Malhotra
- Malaria Group, International Centre for Genetic Engineering and Biotechnology, P. O. Box 10504, Aruna Asaf Ali Marg, New Delhi, 110067, India
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38
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Melville D, Gorur A, Schekman R. Fatty-acid binding protein 5 modulates the SAR1 GTPase cycle and enhances budding of large COPII cargoes. Mol Biol Cell 2018; 30:387-399. [PMID: 30485159 PMCID: PMC6589570 DOI: 10.1091/mbc.e18-09-0548] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
COPII-coated vesicles are the primary mediators of ER-to-Golgi trafficking. Sar1, one of the five core COPII components, is a highly conserved small GTPase, which, upon GTP binding, recruits the other COPII proteins to the ER membrane. It has been hypothesized that the changes in the kinetics of SAR1 GTPase may allow for the secretion of large cargoes. Here we developed a cell-free assay to recapitulate COPII-dependent budding of large lipoprotein cargoes from the ER. We identified fatty-acid binding protein 5 (FABP5) as an enhancer of this budding process. We found that FABP5 promotes the budding of particles ∼150 nm in diameter and modulates the kinetics of the SAR1 GTPase cycle. We further found that FABP5 enhances the trafficking of lipoproteins and of other cargoes, including collagen. These data identify a novel regulator of SAR1 GTPase activity and highlight the importance of this activity for trafficking of large cargoes.
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Affiliation(s)
- David Melville
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720
| | - Amita Gorur
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720
| | - Randy Schekman
- Department of Molecular and Cell Biology, Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, CA 94720
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39
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Aridor M. COPII gets in shape: Lessons derived from morphological aspects of early secretion. Traffic 2018; 19:823-839. [DOI: 10.1111/tra.12603] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 06/26/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022]
Affiliation(s)
- Meir Aridor
- Department of Cell Biology; University of Pittsburgh School of Medicine; Pittsburgh Pennsylvania
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40
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Schenk NA, Dahl PJ, Hanna MG, Audhya A, Tall GG, Knight JD, Anantharam A. A simple supported tubulated bilayer system for evaluating protein-mediated membrane remodeling. Chem Phys Lipids 2018; 215:18-28. [PMID: 30012406 DOI: 10.1016/j.chemphyslip.2018.06.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 06/29/2018] [Indexed: 01/31/2023]
Abstract
Fusion and fission of cellular membranes involve dramatic, protein-mediated changes in membrane curvature. Many of the experimental methods useful for investigating curvature sensing or generation require specialized equipment. We have developed a system based on supported lipid bilayers (SLBs) in which lipid tubules are simple to produce and several types of membrane remodeling events can be readily imaged using widely available instrumentation (e.g., tubule fission and/or membrane budding). Briefly, high ionic strength during lipid bilayer deposition results in incorporation of excess lipids in the SLB. After sequentially washing with water and physiological ionic strength buffer solutions, lipid tubules form spontaneously. We find that tubule formation results from solution-dependent spreading of the SLB; washing from water into physiological ionic strength buffer solution leads to expansion of the bilayer and formation of tubules. Conversely, washing from physiological buffer into water results in contraction of the membrane and loss of tubules. We demonstrate the utility of these supported tubulated bilayers, termed "STuBs," with an investigation of Sar1B, a small Ras family G-protein known to influence membrane curvature. The addition of Sar1B to STuBs results in dramatic changes in tubule topology and eventual tubule fission. Overall, STuBs are a simple experimental system, useful for monitoring protein-mediated effects on membrane topology in real time, under physiologically relevant conditions.
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Affiliation(s)
- Noah A Schenk
- Department of Pharmacology, University of Michigan, United States
| | - Peter J Dahl
- Department of Pharmacology, University of Michigan, United States
| | - Michael G Hanna
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, United States
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, United States
| | - Gregory G Tall
- Department of Pharmacology, University of Michigan, United States
| | | | - Arun Anantharam
- Department of Pharmacology, University of Michigan, United States.
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41
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Hanna MG, Peotter JL, Frankel EB, Audhya A. Membrane Transport at an Organelle Interface in the Early Secretory Pathway: Take Your Coat Off and Stay a While: Evolution of the metazoan early secretory pathway. Bioessays 2018; 40:e1800004. [PMID: 29741780 PMCID: PMC6166410 DOI: 10.1002/bies.201800004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 04/09/2018] [Indexed: 01/25/2023]
Abstract
Most metazoan organisms have evolved a mildly acidified and calcium diminished sorting hub in the early secretory pathway commonly referred to as the Endoplasmic Reticulum-Golgi intermediate compartment (ERGIC). These membranous vesicular-tubular clusters are found tightly juxtaposed to ER subdomains that are competent for the production of COPII-coated transport carriers. In contrast to many unicellular systems, metazoan COPII carriers largely transit just a few hundred nanometers to the ERGIC, prior to COPI-dependent transport on to the cis-Golgi. The mechanisms underlying formation and maintenance of ERGIC membranes are poorly defined. However, recent evidence suggests an important role for Trk-fused gene (TFG) in regulating the integrity of the ER/ERGIC interface. Moreover, in the absence of cytoskeletal elements to scaffold tracks on which COPII carriers might move, TFG appears to promote anterograde cargo transport by locally tethering COPII carriers adjacent to ERGIC membranes. This action, regulated in part by the intrinsically disordered domain of TFG, provides sufficient time for COPII coat disassembly prior to heterotypic membrane fusion and cargo delivery to the ERGIC.
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Affiliation(s)
- Michael G. Hanna
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health 440 Henry Mall, Madison, WI 53706, USA,
| | - Jennifer L. Peotter
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health 440 Henry Mall, Madison, WI 53706, USA,
| | - E. B. Frankel
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health 440 Henry Mall, Madison, WI 53706, USA,
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health 440 Henry Mall, Madison, WI 53706, USA,
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42
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Melero A, Chiaruttini N, Karashima T, Riezman I, Funato K, Barlowe C, Riezman H, Roux A. Lysophospholipids Facilitate COPII Vesicle Formation. Curr Biol 2018; 28:1950-1958.e6. [PMID: 29887313 PMCID: PMC6013297 DOI: 10.1016/j.cub.2018.04.076] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 03/05/2018] [Accepted: 04/24/2018] [Indexed: 12/15/2022]
Abstract
Coat protein complex II (COPII) proteins form vesicles from the endoplasmic reticulum to export cargo molecules to the Golgi apparatus. Among the many proteins involved in this process, Sec12 is a key regulator, functioning as the guanosine diphosphate (GDP) exchange factor for Sar1p, the small guanosine triphosphatase (GTPase) that initiates COPII assembly. Here we show that overexpression of phospholipase B3 in the thermosensitive sec12-4 mutant partially restores growth and protein transport at non-permissive temperatures. Lipidomics analyses of these cells show a higher content of lysophosphatidylinositol (lysoPI), consistent with the lipid specificity of PLB3. Furthermore, we show that lysoPI is specifically enriched in COPII vesicles isolated from in vitro budding assays. As these results suggested that lysophospholipids could facilitate budding under conditions of defective COPII coat dynamics, we reconstituted COPII binding onto giant liposomes with purified proteins and showed that lysoPI decreases membrane rigidity and enhances COPII recruitment to liposomes. Our results support a mechanical facilitation of COPII budding by lysophospholipids. COPII mutant sec12-4 is rescued by the overexpression of an ER resident phospholipase Lipidomic analysis of COPII vesicles shows enrichment in lysophospholipids Recruitment of COPII proteins to liposomes increases in presence of lysophospholipids Lysophosphatidylinositol lowers the rigidity of membranes in vitro
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Affiliation(s)
- Alejandro Melero
- Department of Biochemistry, University of Geneva, 1211 Geneva, Switzerland; Swiss National Centre for Competence in Research in Chemical Biology, 1211 Geneva, Switzerland
| | | | - Takefumi Karashima
- Department of Bioresource Science and Technology, Hiroshima University, Hiroshima 739-8528, Japan
| | - Isabelle Riezman
- Department of Biochemistry, University of Geneva, 1211 Geneva, Switzerland
| | - Kouichi Funato
- Department of Bioresource Science and Technology, Hiroshima University, Hiroshima 739-8528, Japan
| | - Charles Barlowe
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755-3844, USA
| | - Howard Riezman
- Department of Biochemistry, University of Geneva, 1211 Geneva, Switzerland; Swiss National Centre for Competence in Research in Chemical Biology, 1211 Geneva, Switzerland.
| | - Aurélien Roux
- Department of Biochemistry, University of Geneva, 1211 Geneva, Switzerland; Swiss National Centre for Competence in Research in Chemical Biology, 1211 Geneva, Switzerland.
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43
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Suda Y, Kurokawa K, Nakano A. Regulation of ER-Golgi Transport Dynamics by GTPases in Budding Yeast. Front Cell Dev Biol 2018; 5:122. [PMID: 29473037 PMCID: PMC5810278 DOI: 10.3389/fcell.2017.00122] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 12/28/2017] [Indexed: 01/21/2023] Open
Abstract
A large number of proteins are synthesized de novo in the endoplasmic reticulum (ER). They are transported through the Golgi apparatus and then delivered to their proper destinations. The ER and the Golgi play a central role in protein processing and sorting and show dynamic features in their forms. Ras super family small GTPases mediate the protein transport through and between these organelles. The ER-localized GTPase, Sar1, facilitates the formation of COPII transport carriers at the ER exit sites (ERES) on the ER for the transport of cargo proteins from the ER to the Golgi. The Golgi-localized GTPase, Arf1, controls intra-Golgi, and Golgi-to-ER transport of cargo proteins by the formation of COPI carriers. Rab GTPases localized at the Golgi, which are responsible for fusion of membranes, are thought to establish the identities of compartments. Recent evidence suggests that these small GTPases regulate not only discrete sites for generation/fusion of transport carriers, but also membrane dynamics of the organelles where they locate to ensure the integrity of transport. Here we summarize the current understandings about the membrane traffic between these organelles and highlight the cutting-edge advances from super-resolution live imaging of budding yeast, Saccharomyces cerevisiae.
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Affiliation(s)
- Yasuyuki Suda
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan.,Laboratory of Molecular Cell Biology, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Kazuo Kurokawa
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan
| | - Akihiko Nakano
- Live Cell Super-Resolution Imaging Research Team, RIKEN Center for Advanced Photonics, Saitama, Japan.,Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Tokyo, Japan
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44
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Cutrona MB, Morgan NE, Simpson JC. Heritable Skeletal Disorders Arising from Defects in Processing and Transport of Type I Procollagen from the ER: Perspectives on Possible Therapeutic Approaches. Handb Exp Pharmacol 2018; 245:191-225. [PMID: 29071510 DOI: 10.1007/164_2017_67] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Rare bone disorders are a heterogeneous group of diseases, initially associated with mutations in type I procollagen (PC) genes. Recent developments from dissection at the molecular and cellular level have expanded the list of disease-causing proteins, revealing that disruption of the machinery that handles protein secretion can lead to failure in PC secretion and in several cases result in skeletal dysplasia. In parallel, cell-based in vitro studies of PC trafficking pathways offer clues to the identification of new disease candidate genes. Together, this raises the prospect of heritable bone disorders as a paradigm for biosynthetic protein traffic-related diseases, and an avenue through which therapeutic strategies can be explored.Here, we focus on human syndromes linked to defects in type I PC secretion with respect to the landscape of biosynthetic and protein transport steps within the early secretory pathway. We provide a perspective on possible therapeutic interventions for associated heritable craniofacial and skeletal disorders, considering different orders of complexity, from the cellular level by manipulation of proteostasis pathways to higher levels involving cell-based therapies for bone repair and regeneration.
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Affiliation(s)
- Meritxell B Cutrona
- School of Biology and Environmental Science, Conway Institute of Biomolecular and Biomedical Research, University College Dublin (UCD), Dublin, Ireland
| | - Niamh E Morgan
- School of Biology and Environmental Science, Conway Institute of Biomolecular and Biomedical Research, University College Dublin (UCD), Dublin, Ireland
| | - Jeremy C Simpson
- School of Biology and Environmental Science, Conway Institute of Biomolecular and Biomedical Research, University College Dublin (UCD), Dublin, Ireland.
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TFG facilitates outer coat disassembly on COPII transport carriers to promote tethering and fusion with ER-Golgi intermediate compartments. Proc Natl Acad Sci U S A 2017; 114:E7707-E7716. [PMID: 28851831 DOI: 10.1073/pnas.1709120114] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The conserved coat protein complex II (COPII) mediates the initial steps of secretory protein trafficking by assembling onto subdomains of the endoplasmic reticulum (ER) in two layers to generate cargo-laden transport carriers that ultimately fuse with an adjacent ER-Golgi intermediate compartment (ERGIC). Here, we demonstrate that Trk-fused gene (TFG) binds directly to the inner layer of the COPII coat. Specifically, the TFG C terminus interacts with Sec23 through a shared interface with the outer COPII coat and the cargo receptor Tango1/cTAGE5. Our findings indicate that TFG binding to Sec23 outcompetes these other associations in a concentration-dependent manner and ultimately promotes outer coat dissociation. Additionally, we demonstrate that TFG tethers vesicles harboring the inner COPII coat, which contributes to their clustering between the ER and ERGIC in cells. Together, our studies define a mechanism by which COPII transport carriers are retained locally at the ER/ERGIC interface after outer coat disassembly, which is a prerequisite for fusion with ERGIC membranes.
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46
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Saito K, Maeda M, Katada T. Regulation of the Sar1 GTPase Cycle Is Necessary for Large Cargo Secretion from the Endoplasmic Reticulum. Front Cell Dev Biol 2017; 5:75. [PMID: 28879181 PMCID: PMC5572378 DOI: 10.3389/fcell.2017.00075] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 08/10/2017] [Indexed: 12/22/2022] Open
Abstract
Proteins synthesized within the endoplasmic reticulum (ER) are transported to the Golgi via coat protein complex II (COPII)-coated vesicles. The formation of COPII-coated vesicles is regulated by the GTPase cycle of Sar1. Activated Sar1 is recruited to ER membranes and forms a pre-budding complex with cargoes and the inner-coat complex. The outer-coat complex then stimulates Sar1 inactivation and completes vesicle formation. The mechanisms of forming transport carriers are well-conserved among species; however, in mammalian cells, several cargo molecules such as collagen, and chylomicrons are too large to be accommodated in conventional COPII-coated vesicles. Thus, special cargo-receptor complexes are required for their export from the ER. cTAGE5/TANGO1 complexes and their isoforms have been identified as cargo receptors for these macromolecules. Recent reports suggest that the cTAGE5/TANGO1 complex interacts with the GEF and the GAP of Sar1 and tightly regulates its GTPase cycle to accomplish large cargo secretion.
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Affiliation(s)
- Kota Saito
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, University of TokyoTokyo, Japan
| | - Miharu Maeda
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, University of TokyoTokyo, Japan
| | - Toshiaki Katada
- Department of Physiological Chemistry, Graduate School of Pharmaceutical Sciences, University of TokyoTokyo, Japan
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47
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Rout MP, Field MC. The Evolution of Organellar Coat Complexes and Organization of the Eukaryotic Cell. Annu Rev Biochem 2017; 86:637-657. [DOI: 10.1146/annurev-biochem-061516-044643] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Mark C. Field
- Wellcome Trust Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom
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48
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Cicenas J, Tamosaitis L, Kvederaviciute K, Tarvydas R, Staniute G, Kalyan K, Meskinyte-Kausiliene E, Stankevicius V, Valius M. KRAS, NRAS and BRAF mutations in colorectal cancer and melanoma. Med Oncol 2017; 34:26. [DOI: 10.1007/s12032-016-0879-9] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2016] [Accepted: 12/29/2016] [Indexed: 01/13/2023]
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49
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Jarsch IK, Daste F, Gallop JL. Membrane curvature in cell biology: An integration of molecular mechanisms. J Cell Biol 2016; 214:375-87. [PMID: 27528656 PMCID: PMC4987295 DOI: 10.1083/jcb.201604003] [Citation(s) in RCA: 220] [Impact Index Per Article: 27.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 07/29/2016] [Indexed: 01/03/2023] Open
Abstract
Curving biological membranes establishes the complex architecture of the cell and mediates membrane traffic to control flux through subcellular compartments. Common molecular mechanisms for bending membranes are evident in different cell biological contexts across eukaryotic phyla. These mechanisms can be intrinsic to the membrane bilayer (either the lipid or protein components) or can be brought about by extrinsic factors, including the cytoskeleton. Here, we review examples of membrane curvature generation in animals, fungi, and plants. We showcase the molecular mechanisms involved and how they collaborate and go on to highlight contexts of curvature that are exciting areas of future research. Lessons from how membranes are bent in yeast and mammals give hints as to the molecular mechanisms we expect to see used by plants and protists.
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Affiliation(s)
- Iris K Jarsch
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, England, UK
| | - Frederic Daste
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, England, UK
| | - Jennifer L Gallop
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, England, UK
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50
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G2385R and I2020T Mutations Increase LRRK2 GTPase Activity. BIOMED RESEARCH INTERNATIONAL 2016; 2016:7917128. [PMID: 27314038 PMCID: PMC4897664 DOI: 10.1155/2016/7917128] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 04/24/2016] [Accepted: 04/26/2016] [Indexed: 11/18/2022]
Abstract
The LRRK2 mutation is a major causal mutation in familial Parkinson's disease. Although LRRK2 contains functional GTPase and kinase domains and their activities are altered by pathogenic mutations, most studies focused on LRRK2 kinase activity because the most prevalent mutant, G2019S, enhances kinase activity. However, the G2019S mutation is extremely rare in the Asian population. Instead, the G2385R mutation was reported as a major risk factor in the Asian population. Similar to other LRRK2 studies, G2385R studies have also focused on kinase activity. Here, we investigated GTPase activities of G2385R with other LRRK2 mutants, such as G2019S, R1441C, and I2020T, as well as wild type (WT). Our results suggest that both I2020T and G2385R contain GTPase activities stronger than that of WT. A kinase assay using the commercial recombinant proteins showed that I2020T harbored stronger activity, whereas G2385R had weaker activity than that of WT, as reported previously. This is the first report of LRRK2 I2020T and G2385R GTPase activities and shows that most of the LRRK2 mutations that are pathogenic or a risk factor altered either kinase or GTPase activity, suggesting that their physiological consequences are caused by altered enzyme activities.
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