51
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Castle JD. Separating Pathways in the Extracellular ESCRT Service. Biophys J 2017; 113:1179-1180. [PMID: 28842110 DOI: 10.1016/j.bpj.2017.08.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 08/08/2017] [Indexed: 11/30/2022] Open
Affiliation(s)
- J David Castle
- Department of Cell Biology and Center for Cell and Membrane Physiology, University of Virginia School of Medicine, Charlottesville, Virginia.
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52
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Katanin spiral and ring structures shed light on power stroke for microtubule severing. Nat Struct Mol Biol 2017; 24:717-725. [PMID: 28783150 PMCID: PMC7152510 DOI: 10.1038/nsmb.3448] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 07/07/2017] [Indexed: 01/07/2023]
Abstract
Microtubule-severing enzymes katanin, spastin and fidgetin are AAA ATPases important for the biogenesis and maintenance of complex microtubule arrays in axons, spindles and cilia. Because of a lack of known 3D structures for these enzymes, their mechanism of action has remained poorly understood. Here we report the X-ray crystal structure of the monomeric AAA katanin module from Caenorhabditis elegans and cryo-EM reconstructions of the hexamer in two conformations. The structures reveal an unexpected asymmetric arrangement of the AAA domains mediated by structural elements unique to microtubule-severing enzymes and critical for their function. The reconstructions show that katanin cycles between open spiral and closed ring conformations, depending on the ATP occupancy of a gating protomer that tenses or relaxes interprotomer interfaces. Cycling of the hexamer between these conformations would provide the power stroke for microtubule severing.
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53
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Horner DS, Pasini ME, Beltrame M, Mastrodonato V, Morelli E, Vaccari T. ESCRT genes and regulation of developmental signaling. Semin Cell Dev Biol 2017; 74:29-39. [PMID: 28847745 DOI: 10.1016/j.semcdb.2017.08.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 08/06/2017] [Accepted: 08/18/2017] [Indexed: 11/30/2022]
Abstract
ESCRT (Endosomal Sorting Complex Required for Transport) proteins have been shown to control an increasing number of membrane-associated processes. Some of these, and prominently regulation of receptor trafficking, profoundly shape signal transduction. Evidence in fungi, plants and multiple animal models support the emerging concept that ESCRTs are main actors in coordination of signaling with the changes in cells and tissues occurring during development and homeostasis. Consistent with their pleiotropic function, ESCRTs are regulated in multiple ways to tailor signaling to developmental and homeostatic needs. ESCRT activity is crucial to correct execution of developmental programs, especially at key transitions, allowing eukaryotes to thrive and preventing appearance of congenital defects.
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Affiliation(s)
- David S Horner
- Dipartimento di Bioscienze, Universita' degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
| | - Maria E Pasini
- Dipartimento di Bioscienze, Universita' degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
| | - Monica Beltrame
- Dipartimento di Bioscienze, Universita' degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
| | - Valeria Mastrodonato
- IFOM, The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milano, Italy
| | - Elena Morelli
- IFOM, The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milano, Italy
| | - Thomas Vaccari
- Dipartimento di Bioscienze, Universita' degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy; IFOM, The FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milano, Italy.
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54
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Chiaruttini N, Roux A. Dynamic and elastic shape transitions in curved ESCRT-III filaments. Curr Opin Cell Biol 2017; 47:126-135. [PMID: 28728013 DOI: 10.1016/j.ceb.2017.07.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The ESCRT-III complex is an evolutionary ancient and conserved complex that catalyzes fission of lipid membranes from the lumen of the neck in many, if not all processes requiring this specific fission reaction. The ESCRT-III membrane remodeling complex is unique as its molecular and polymeric structures do not intuitively suggests how it could deform and break lipid membranes. Here we review the common structural features of the ESCRT-III subunits, and the shape diversity of the various filamentous forms. We propose a simple geometry and elasticity framework that could help to isolate which features of the ESCRT-III filaments are common to all filamentous forms as well as to explain their diversity. We speculate on how these features could provide mechanistic insights into the many functions of the ESCRT-III complex.
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Affiliation(s)
- Nicolas Chiaruttini
- Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Aurélien Roux
- Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland; Swiss National Centre for Competence in Research Programme Chemical Biology, CH-1211 Geneva, Switzerland.
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55
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Lippincott-Schwartz J, Freed EO, van Engelenburg SB. A Consensus View of ESCRT-Mediated Human Immunodeficiency Virus Type 1 Abscission. Annu Rev Virol 2017; 4:309-325. [PMID: 28715971 DOI: 10.1146/annurev-virology-101416-041840] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The strong dependence of retroviruses, such as human immunodeficiency virus type 1 (HIV-1), on host cell factors is no more apparent than when the endosomal sorting complex required for transport (ESCRT) machinery is purposely disengaged. The resulting potent inhibition of retrovirus release underscores the importance of understanding fundamental structure-function relationships at the ESCRT-HIV-1 interface. Recent studies utilizing advanced imaging technologies have helped clarify these relationships, overcoming hurdles to provide a range of potential models for ESCRT-mediated virus abscission. Here, we discuss these models in the context of prior work detailing ESCRT machinery and the HIV-1 release process. To provide a template for further refinement, we propose a new working model for ESCRT-mediated HIV-1 release that reconciles disparate and seemingly conflicting studies.
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Affiliation(s)
| | - E O Freed
- The Virus-Cell Interaction Section, HIV Dynamics and Replication Program, National Cancer Institute, Frederick, Maryland 21701
| | - S B van Engelenburg
- Department of Biological Sciences, University of Denver, Denver, Colorado 80210;
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56
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Ye Q, Kim DH, Dereli I, Rosenberg SC, Hagemann G, Herzog F, Tóth A, Cleveland DW, Corbett KD. The AAA+ ATPase TRIP13 remodels HORMA domains through N-terminal engagement and unfolding. EMBO J 2017; 36:2419-2434. [PMID: 28659378 DOI: 10.15252/embj.201797291] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2017] [Revised: 05/30/2017] [Accepted: 06/06/2017] [Indexed: 12/22/2022] Open
Abstract
Proteins of the conserved HORMA domain family, including the spindle assembly checkpoint protein MAD2 and the meiotic HORMADs, assemble into signaling complexes by binding short peptides termed "closure motifs". The AAA+ ATPase TRIP13 regulates both MAD2 and meiotic HORMADs by disassembling these HORMA domain-closure motif complexes, but its mechanisms of substrate recognition and remodeling are unknown. Here, we combine X-ray crystallography and crosslinking mass spectrometry to outline how TRIP13 recognizes MAD2 with the help of the adapter protein p31comet We show that p31comet binding to the TRIP13 N-terminal domain positions the disordered MAD2 N-terminus for engagement by the TRIP13 "pore loops", which then unfold MAD2 in the presence of ATP N-terminal truncation of MAD2 renders it refractory to TRIP13 action in vitro, and in cells causes spindle assembly checkpoint defects consistent with loss of TRIP13 function. Similar truncation of HORMAD1 in mouse spermatocytes compromises its TRIP13-mediated removal from meiotic chromosomes, highlighting a conserved mechanism for recognition and disassembly of HORMA domain-closure motif complexes by TRIP13.
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Affiliation(s)
- Qiaozhen Ye
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA
| | - Dong Hyun Kim
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA
| | - Ihsan Dereli
- Institute of Physiological Chemistry, Faculty of Medicine at the TU Dresden, Dresden, Germany
| | - Scott C Rosenberg
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA.,Department of Chemistry, University of California, San Diego, La Jolla, CA, USA
| | - Goetz Hagemann
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Franz Herzog
- Gene Center Munich and Department of Biochemistry, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Attila Tóth
- Institute of Physiological Chemistry, Faculty of Medicine at the TU Dresden, Dresden, Germany
| | - Don W Cleveland
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
| | - Kevin D Corbett
- Ludwig Institute for Cancer Research, San Diego Branch, La Jolla, CA, USA .,Department of Chemistry, University of California, San Diego, La Jolla, CA, USA.,Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA, USA
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57
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Mierzwa BE, Chiaruttini N, Redondo-Morata L, von Filseck JM, König J, Larios J, Poser I, Müller-Reichert T, Scheuring S, Roux A, Gerlich DW. Dynamic subunit turnover in ESCRT-III assemblies is regulated by Vps4 to mediate membrane remodelling during cytokinesis. Nat Cell Biol 2017; 19:787-798. [PMID: 28604678 PMCID: PMC5493987 DOI: 10.1038/ncb3559] [Citation(s) in RCA: 156] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Accepted: 05/19/2017] [Indexed: 02/07/2023]
Abstract
The Endosomal Sorting Complex Required for Transport (ESCRT)-III mediates membrane fission in fundamental cellular processes, including cytokinesis. ESCRT-III is thought to form persistent filaments that over time increase their curvature to constrict membranes. Unexpectedly, we found that ESCRT-III at the midbody of human cells rapidly turns over subunits with cytoplasmic pools while gradually forming larger assemblies. ESCRT-III turnover depended on the ATPase VPS4, which accumulated at the midbody simultaneously with ESCRT-III subunits, and was required for assembly of functional ESCRT-III structures. In vitro, the Vps2/Vps24 subunits of ESCRT-III formed side-by-side filaments with Snf7 and inhibited further polymerization, but the growth inhibition was alleviated by the addition of Vps4 and ATP. High-speed atomic force microscopy further revealed highly dynamic arrays of growing and shrinking ESCRT-III spirals in presence of Vps4. Continuous ESCRT-III remodeling by subunit turnover might facilitate shape adaptions to variable membrane geometries, with broad implications for diverse cellular processes.
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Affiliation(s)
- Beata E Mierzwa
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), AT-1030 Vienna, Austria
| | - Nicolas Chiaruttini
- Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | | | | | - Julia König
- Experimental Center, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, D-01307 Dresden, Germany
| | - Jorge Larios
- Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland
| | - Ina Poser
- Max Planck Institute of Molecular Cell Biology and Genetics, D-01307 Dresden, Germany
| | - Thomas Müller-Reichert
- Experimental Center, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, D-01307 Dresden, Germany
| | - Simon Scheuring
- U1006 INSERM, Aix-Marseille Université, 13009 Marseille, France
| | - Aurélien Roux
- Department of Biochemistry, University of Geneva, CH-1211 Geneva, Switzerland.,Swiss National Centre for Competence in Research Programme Chemical Biology, CH-1211 Geneva, Switzerland
| | - Daniel W Gerlich
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna Biocenter (VBC), AT-1030 Vienna, Austria
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58
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Monroe N, Han H, Shen PS, Sundquist WI, Hill CP. Structural basis of protein translocation by the Vps4-Vta1 AAA ATPase. eLife 2017; 6. [PMID: 28379137 PMCID: PMC5413351 DOI: 10.7554/elife.24487] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 04/04/2017] [Indexed: 12/18/2022] Open
Abstract
Many important cellular membrane fission reactions are driven by ESCRT pathways, which culminate in disassembly of ESCRT-III polymers by the AAA ATPase Vps4. We report a 4.3 Å resolution cryo-EM structure of the active Vps4 hexamer with its cofactor Vta1, ADP·BeFx, and an ESCRT-III substrate peptide. Four Vps4 subunits form a helix whose interfaces are consistent with ATP binding, is stabilized by Vta1, and binds the substrate peptide. The fifth subunit approximately continues this helix but appears to be dissociating. The final Vps4 subunit completes a notched-washer configuration as if transitioning between the ends of the helix. We propose that ATP binding propagates growth at one end of the helix while hydrolysis promotes disassembly at the other end, so that Vps4 ‘walks’ along ESCRT-III until it encounters the ordered N-terminal domain to destabilize the ESCRT-III lattice. This model may be generally applicable to other protein-translocating AAA ATPases. DOI:http://dx.doi.org/10.7554/eLife.24487.001 Membranes surround multiple compartments within cells as well as the cell itself. In living cells, these membranes are remodeled continuously. This allows cells to divide, move molecules between different compartments and perform other essential activities. One important remodeling event is known as fission, which splits a membrane into separate parts. Large repeating structures (or polymers) of ESCRT-III proteins play a crucial role in membrane fission. Breaking apart ESCRT-III polymers triggers membrane fission and also recycles the ESCRT-III proteins so that they can be used again. An enzyme called Vps4 converts chemical energy (stored in the form of a molecule called ATP) into the mechanical force that breaks apart the ESCRT-III polymers. The active form of Vps4 consists of six Vps4 subunits working together to form a complex that includes a cofactor protein called Vta1. Monroe et al. have now used a technique called cryo-electron microscopy to determine the structure of an active yeast Vps4-Vta1 complex while it is bound to a segment of an ESCRT-III protein. This revealed that four of the six Vps4 subunits form a helix (which resembles a spiral staircase) that binds ESCRT-III in its central pore. The structure implies that binding of ATP causes the Vps4 helix to grow at one end and that converting ATP into a molecule called ADP (to release energy) causes disassembly at the other end. The two additional Vps4 subunits move from the disassembling end to the growing end of the helix. In this manner, Vps4 ‘walks’ along ESCRT-III, thereby pulling it through the pore at the center of the Vps4 complex and triggering breakdown of the ESCRT-III polymer. Further work is now needed to understand exactly how this activity leads to membrane fission. DOI:http://dx.doi.org/10.7554/eLife.24487.002
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Affiliation(s)
- Nicole Monroe
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Han Han
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Peter S Shen
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Wesley I Sundquist
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
| | - Christopher P Hill
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, United States
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59
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Su M, Guo EZ, Ding X, Li Y, Tarrasch JT, Brooks CL, Xu Z, Skiniotis G. Mechanism of Vps4 hexamer function revealed by cryo-EM. SCIENCE ADVANCES 2017; 3:e1700325. [PMID: 28439563 PMCID: PMC5392032 DOI: 10.1126/sciadv.1700325] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 02/11/2017] [Indexed: 05/08/2023]
Abstract
Vps4 is a member of AAA+ ATPase (adenosine triphosphatase associated with diverse cellular activities) that operates as an oligomer to disassemble ESCRT-III (endosomal sorting complex required for transport III) filaments, thereby catalyzing the final step in multiple ESCRT-dependent membrane remodeling events. We used electron cryo-microscopy to visualize oligomers of a hydrolysis-deficient Vps4 (vacuolar protein sorting-associated protein 4) mutant in the presence of adenosine 5'-triphosphate (ATP). We show that Vps4 subunits assemble into an asymmetric hexameric ring following an approximate helical path that sequentially stacks substrate-binding loops along the central pore. The hexamer is observed to adopt an open or closed ring configuration facilitated by major conformational changes in a single subunit. The structural transition of the mobile Vps4 subunit results in the repositioning of its substrate-binding loop from the top to the bottom of the central pore, with an associated translation of 33 Å. These structures, along with mutant-doping experiments and functional assays, provide evidence for a sequential and processive ATP hydrolysis mechanism by which Vps4 hexamers disassemble ESCRT-III filaments.
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Affiliation(s)
- Min Su
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Emily Z. Guo
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xinqiang Ding
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Yan Li
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Charles L. Brooks
- Department of Computational Medicine and Bioinformatics, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Zhaohui Xu
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Corresponding author. (G.S.); (Z.X.)
| | - Georgios Skiniotis
- Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biophysics, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, MI 48109, USA
- Corresponding author. (G.S.); (Z.X.)
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60
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Samson RY, Dobro MJ, Jensen GJ, Bell SD. The Structure, Function and Roles of the Archaeal ESCRT Apparatus. Subcell Biochem 2017; 84:357-377. [PMID: 28500532 DOI: 10.1007/978-3-319-53047-5_12] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Although morphologically resembling bacteria, archaea constitute a distinct domain of life with a closer affiliation to eukaryotes than to bacteria. This similarity is seen in the machineries for a number of essential cellular processes, including DNA replication and gene transcription. Perhaps surprisingly, given their prokaryotic morphology, some archaea also possess a core cell division apparatus that is related to that involved in the final stages of membrane abscission in vertebrate cells, the ESCRT machinery.
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Affiliation(s)
- Rachel Y Samson
- Department of Molecular and Cellular Biochemistry, Indiana University, Simon Hall MSB, 212 S Hawthorne Drive, Bloomington, IN, 47405, USA
| | - Megan J Dobro
- School of Natural Science, Hampshire College, Amherst, MA, 01002, USA
| | - Grant J Jensen
- Division of Biology, California Institute of Technology, Pasadena, CA, 91125, USA
- Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Stephen D Bell
- Department of Molecular and Cellular Biochemistry, Indiana University, Simon Hall MSB, 212 S Hawthorne Drive, Bloomington, IN, 47405, USA.
- Department of Biology, Indiana University, Simon Hall MSB, 212 S Hawthorne Drive, Bloomington, IN, 47405, USA.
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61
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Christ L, Raiborg C, Wenzel EM, Campsteijn C, Stenmark H. Cellular Functions and Molecular Mechanisms of the ESCRT Membrane-Scission Machinery. Trends Biochem Sci 2017; 42:42-56. [DOI: 10.1016/j.tibs.2016.08.016] [Citation(s) in RCA: 300] [Impact Index Per Article: 42.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Revised: 08/24/2016] [Accepted: 08/31/2016] [Indexed: 12/22/2022]
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62
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Abstract
As discovered over the past 25 years, the cytoskeletons of bacteria and archaea are complex systems of proteins whose central components are dynamic cytomotive filaments. They perform roles in cell division, DNA partitioning, cell shape determination and the organisation of intracellular components. The protofilament structures and polymerisation activities of various actin-like, tubulin-like and ESCRT-like proteins of prokaryotes closely resemble their eukaryotic counterparts but show greater diversity. Their activities are modulated by a wide range of accessory proteins but these do not include homologues of the motor proteins that supplement filament dynamics to aid eukaryotic cell motility. Numerous other filamentous proteins, some related to eukaryotic IF-proteins/lamins and dynamins etc, seem to perform structural roles similar to those in eukaryotes.
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Affiliation(s)
- Linda A Amos
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
| | - Jan Löwe
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge, CB2 0QH, UK.
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63
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Abstract
The narrow membrane necks formed during viral, exosomal and intra-endosomal budding from membranes, as well as during cytokinesis and related processes, have interiors that are contiguous with the cytosol. Severing these necks involves action from the opposite face of the membrane as occurs during the well-characterized formation of coated vesicles. This 'reverse' (or 'inverse')-topology membrane scission is carried out by the endosomal sorting complex required for transport (ESCRT) proteins, which form filaments, flat spirals, tubes and conical funnels that are thought to direct membrane remodelling and scission. Their assembly, and their disassembly by the ATPase vacuolar protein sorting-associated 4 (VPS4) have been intensively studied, but the mechanism of scission has been elusive. New insights from cryo-electron microscopy and various types of spectroscopy may finally be close to rectifying this situation.
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64
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Potent, Reversible, and Specific Chemical Inhibitors of Eukaryotic Ribosome Biogenesis. Cell 2016; 167:512-524.e14. [PMID: 27667686 PMCID: PMC5116814 DOI: 10.1016/j.cell.2016.08.070] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 07/14/2016] [Accepted: 08/26/2016] [Indexed: 11/21/2022]
Abstract
All cellular proteins are synthesized by ribosomes, whose biogenesis in eukaryotes is a complex multi-step process completed within minutes. Several chemical inhibitors of ribosome function are available and used as tools or drugs. By contrast, we lack potent validated chemical probes to analyze the dynamics of eukaryotic ribosome assembly. Here, we combine chemical and genetic approaches to discover ribozinoindoles (or Rbins), potent and reversible triazinoindole-based inhibitors of eukaryotic ribosome biogenesis. Analyses of Rbin sensitivity and resistance conferring mutations in fission yeast, along with biochemical assays with recombinant proteins, provide evidence that Rbins’ physiological target is Midasin, an essential ∼540-kDa AAA+ (ATPases associated with diverse cellular activities) protein. Using Rbins to acutely inhibit or activate Midasin function, in parallel experiments with inhibitor-sensitive or inhibitor-resistant cells, we uncover Midasin’s role in assembling Nsa1 particles, nucleolar precursors of the 60S subunit. Together, our findings demonstrate that Rbins are powerful probes for eukaryotic ribosome assembly. Ribozinoindoles are potent chemical inhibitors of eukaryotic ribosome assembly Activity of four of Mdn1’s six ATPase sites is likely needed for cell growth Ribozinoindoles inhibit recombinant full-length Mdn1’s ATPase activity in vitro Assembly of Nsa1 particles, precursors of the 60S subunit, depends on Mdn1
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65
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Sun S, Sun L, Zhou X, Wu C, Wang R, Lin SH, Kuang J. Phosphorylation-Dependent Activation of the ESCRT Function of ALIX in Cytokinetic Abscission and Retroviral Budding. Dev Cell 2016; 36:331-43. [PMID: 26859355 DOI: 10.1016/j.devcel.2016.01.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 11/08/2015] [Accepted: 01/04/2016] [Indexed: 11/28/2022]
Abstract
The modular adaptor protein ALIX is a key player in multiple ESCRT-III-mediated membrane remodeling processes. ALIX is normally present in a closed conformation due to an intramolecular interaction that renders ALIX unable to perform its ESCRT functions. Here we demonstrate that M phase-specific phosphorylation of the intramolecular interaction site within the proline-rich domain (PRD) of ALIX transforms cytosolic ALIX from closed to open conformation. Defining the role of this mechanism of ALIX regulation in three classical ESCRT-mediated processes revealed that phosphorylation of the intramolecular interaction site in the PRD is required for ALIX to function in cytokinetic abscission and retroviral budding, but not in multivesicular body sorting of activated epidermal growth factor receptor. Thus, phosphorylation of the intramolecular interaction site in the PRD is one of the major mechanisms that activates the ESCRT function of ALIX.
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Affiliation(s)
- Sheng Sun
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA; Experimental Therapeutics Academic Program, The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA
| | - Le Sun
- AbMax Biotechnology, Beijing 100085, China
| | - Xi Zhou
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA
| | - Chuanfen Wu
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA
| | - Ruoning Wang
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA
| | - Sue-Hwa Lin
- Experimental Therapeutics Academic Program, The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA; Department of Translational Molecular Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jian Kuang
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX 77230, USA; Experimental Therapeutics Academic Program, The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
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66
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Structural Fine-Tuning of MIT-Interacting Motif 2 (MIM2) and Allosteric Regulation of ESCRT-III by Vps4 in Yeast. J Mol Biol 2016; 428:2392-2404. [DOI: 10.1016/j.jmb.2016.04.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 04/04/2016] [Accepted: 04/04/2016] [Indexed: 02/02/2023]
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67
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Closing a gap in the nuclear envelope. Curr Opin Cell Biol 2016; 40:90-97. [PMID: 27016712 DOI: 10.1016/j.ceb.2016.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/13/2016] [Accepted: 03/05/2016] [Indexed: 11/22/2022]
Abstract
The nuclear envelope (NE) ensures nucleo-cytoplasmic compartmentalization, with trafficking of macromolecules across this double membrane controlled by embedded nuclear pore complexes (NPCs). The NE and associated proteins are dismantled during open mitosis and reestablishment of this barrier during mitotic exit requires dynamic remodeling of endoplasmic reticulum (ER) membranes and coordination with NPC reformation, with NPC deposition continuing during subsequent interphase. In this review, we discuss recent progress in our understanding of NE reformation and nuclear pore complex generation, with special focus on work implicating the endosomal sorting complex required for transport (ESCRT) membrane remodeling machinery in these events.
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Alonso Y Adell M, Migliano SM, Teis D. ESCRT-III and Vps4: a dynamic multipurpose tool for membrane budding and scission. FEBS J 2016; 283:3288-302. [PMID: 26910595 DOI: 10.1111/febs.13688] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 01/19/2016] [Accepted: 02/17/2016] [Indexed: 12/11/2022]
Abstract
Complex molecular machineries bud, scission and repair cellular membranes. Components of the multi-subunit endosomal sorting complex required for transport (ESCRT) machinery are enlisted when multivesicular bodies are generated, extracellular vesicles are formed, the plasma membrane needs to be repaired, enveloped viruses bud out of host cells, defective nuclear pores have to be cleared, the nuclear envelope must be resealed after mitosis and for final midbody abscission during cytokinesis. While some ESCRT components are only required for specific processes, the assembly of ESCRT-III polymers on target membranes and the action of the AAA-ATPase Vps4 are mandatory for every process. In this review, we summarize the current knowledge of structural and functional features of ESCRT-III/Vps4 assemblies in the growing pantheon of ESCRT-dependent pathways. We describe specific recruitment processes for ESCRT-III to different membranes, which could be useful to selectively inhibit ESCRT function during specific processes, while not affecting other ESCRT-dependent processes. Finally, we speculate how ESCRT-III and Vps4 might function together and highlight how the characterization of their precise spatiotemporal organization will improve our understanding of ESCRT-mediated membrane budding and scission in vivo.
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Affiliation(s)
| | - Simona M Migliano
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Austria
| | - David Teis
- Division of Cell Biology, Biocenter, Medical University of Innsbruck, Austria.
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69
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Caillat C, Macheboeuf P, Wu Y, McCarthy AA, Boeri-Erba E, Effantin G, Göttlinger HG, Weissenhorn W, Renesto P. Asymmetric ring structure of Vps4 required for ESCRT-III disassembly. Nat Commun 2015; 6:8781. [PMID: 26632262 PMCID: PMC4686814 DOI: 10.1038/ncomms9781] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 10/02/2015] [Indexed: 02/01/2023] Open
Abstract
The vacuolar protein sorting 4 AAA-ATPase (Vps4) recycles endosomal sorting complexes required for transport (ESCRT-III) polymers from cellular membranes. Here we present a 3.6-Å X-ray structure of ring-shaped Vps4 from Metallosphera sedula (MsVps4), seen as an asymmetric pseudohexamer. Conserved key interface residues are shown to be important for MsVps4 assembly, ATPase activity in vitro, ESCRT-III disassembly in vitro and HIV-1 budding. ADP binding leads to conformational changes within the protomer, which might propagate within the ring structure. All ATP-binding sites are accessible and the pseudohexamer binds six ATP with micromolar affinity in vitro. In contrast, ADP occupies one high-affinity and five low-affinity binding sites in vitro, consistent with conformational asymmetry induced on ATP hydrolysis. The structure represents a snapshot of an assembled Vps4 conformation and provides insight into the molecular motions the ring structure undergoes in a concerted action to couple ATP hydrolysis to ESCRT-III substrate disassembly.
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Affiliation(s)
- Christophe Caillat
- Unit of Virus-Host Cell interactions (UVHCI), University of Grenoble Alpes, F-38042 Grenoble, France
- CNRS, UVHCI, 71 avenue des Martyrs, F-38042 Grenoble, France
| | - Pauline Macheboeuf
- Unit of Virus-Host Cell interactions (UVHCI), University of Grenoble Alpes, F-38042 Grenoble, France
- CNRS, UVHCI, 71 avenue des Martyrs, F-38042 Grenoble, France
| | - Yuanfei Wu
- Program in Gene Function and Expression, Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Andrew A. McCarthy
- Unit of Virus-Host Cell interactions (UVHCI), University of Grenoble Alpes, F-38042 Grenoble, France
- European Molecular Biology Laboratory (EMBL), Grenoble Outstation, 71 avenue des Martyrs, F-38042 Grenoble, France
| | - Elisabetta Boeri-Erba
- Institut de Biologie Structurale (IBS), University of Grenoble Alpes, 71 avenue des Martyrs, F-38044 Grenoble, France
- CNRS, IBS, 71 avenue des Martyrs, F-38044 Grenoble, France
- CEA, IBS, 71 avenue des Martyrs F-38044 Grenoble, France
| | - Gregory Effantin
- Unit of Virus-Host Cell interactions (UVHCI), University of Grenoble Alpes, F-38042 Grenoble, France
- CNRS, UVHCI, 71 avenue des Martyrs, F-38042 Grenoble, France
| | - Heinrich G. Göttlinger
- Program in Gene Function and Expression, Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
| | - Winfried Weissenhorn
- Unit of Virus-Host Cell interactions (UVHCI), University of Grenoble Alpes, F-38042 Grenoble, France
- CNRS, UVHCI, 71 avenue des Martyrs, F-38042 Grenoble, France
| | - Patricia Renesto
- Unit of Virus-Host Cell interactions (UVHCI), University of Grenoble Alpes, F-38042 Grenoble, France
- CNRS, UVHCI, 71 avenue des Martyrs, F-38042 Grenoble, France
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70
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Monroe N, Hill CP. Meiotic Clade AAA ATPases: Protein Polymer Disassembly Machines. J Mol Biol 2015; 428:1897-911. [PMID: 26555750 DOI: 10.1016/j.jmb.2015.11.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 11/03/2015] [Accepted: 11/04/2015] [Indexed: 12/20/2022]
Abstract
Meiotic clade AAA ATPases (ATPases associated with diverse cellular activities), which were initially grouped on the basis of phylogenetic classification of their AAA ATPase cassette, include four relatively well characterized family members, Vps4, spastin, katanin and fidgetin. These enzymes all function to disassemble specific polymeric protein structures, with Vps4 disassembling the ESCRT-III polymers that are central to the many membrane-remodeling activities of the ESCRT (endosomal sorting complexes required for transport) pathway and spastin, katanin p60 and fidgetin affecting multiple aspects of cellular dynamics by severing microtubules. They share a common domain architecture that features an N-terminal MIT (microtubule interacting and trafficking) domain followed by a single AAA ATPase cassette. Meiotic clade AAA ATPases function as hexamers that can cycle between the active assembly and inactive monomers/dimers in a regulated process, and they appear to disassemble their polymeric substrates by translocating subunits through the central pore of their hexameric ring. Recent studies with Vps4 have shown that nucleotide-induced asymmetry is a requirement for substrate binding to the pore loops and that recruitment to the protein lattice via MIT domains also relieves autoinhibition and primes the AAA ATPase cassettes for substrate binding. The most striking, unifying feature of meiotic clade AAA ATPases may be their MIT domain, which is a module that is found in a wide variety of proteins that localize to ESCRT-III polymers. Spastin also displays an adjacent microtubule binding sequence, and the presence of both ESCRT-III and microtubule binding elements may underlie the recent findings that the ESCRT-III disassembly function of Vps4 and the microtubule-severing function of spastin, as well as potentially katanin and fidgetin, are highly coordinated.
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Affiliation(s)
- Nicole Monroe
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112-5650, USA
| | - Christopher P Hill
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT 84112-5650, USA.
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71
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Tan J, Davies BA, Payne JA, Benson LM, Katzmann DJ. Conformational Changes in the Endosomal Sorting Complex Required for the Transport III Subunit Ist1 Lead to Distinct Modes of ATPase Vps4 Regulation. J Biol Chem 2015; 290:30053-65. [PMID: 26515066 DOI: 10.1074/jbc.m115.665604] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Indexed: 11/06/2022] Open
Abstract
Intralumenal vesicle formation of the multivesicular body is a critical step in the delivery of endocytic cargoes to the lysosome for degradation. Endosomal sorting complex required for transport III (ESCRT-III) subunits polymerize on endosomal membranes to facilitate membrane budding away from the cytoplasm to generate these intralumenal vesicles. The ATPase Vps4 remodels and disassembles ESCRT-III, but the manner in which Vps4 activity is coordinated with ESCRT-III function remains unclear. Ist1 is structurally homologous to ESCRT-III subunits and has been reported to inhibit Vps4 function despite the presence of a microtubule-interacting and trafficking domain-interacting motif (MIM) capable of stimulating Vps4 in the context of other ESCRT-III subunits. Here we report that Ist1 inhibition of Vps4 ATPase activity involves two elements in Ist1: the MIM itself and a surface containing a conserved ELYC sequence. In contrast, the MIM interaction, in concert with a more open conformation of the Ist1 core, resulted in stimulation of Vps4. Addition of the ESCRT-III subunit binding partner of Ist1, Did2, also converted Ist1 from an inhibitor to a stimulator of Vps4 ATPase activity. Finally, distinct regulation of Vps4 by Ist1 corresponded with altered ESCRT-III disassembly in vitro. Together, these data support a model in which Ist1-Did2 interactions during ESCRT-III polymerization coordinate Vps4 activity with the timing of ESCRT-III disassembly.
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Affiliation(s)
- Jason Tan
- From the Biochemistry and Molecular Biology Department, Mayo Graduate School, and
| | | | | | - Linda M Benson
- Mayo Medical Genome Facility Proteomics Core, Mayo Clinic, Rochester, Minnesota 55905
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72
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Webster BM, Lusk CP. Border Safety: Quality Control at the Nuclear Envelope. Trends Cell Biol 2015; 26:29-39. [PMID: 26437591 DOI: 10.1016/j.tcb.2015.08.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 07/27/2015] [Accepted: 08/07/2015] [Indexed: 10/23/2022]
Abstract
The unique biochemical identity of the nuclear envelope confers its capacity to establish a barrier that protects the nuclear compartment and directly contributes to nuclear function. Recent work uncovered quality control mechanisms employing the endosomal sorting complexes required for transport (ESCRT) machinery and a new arm of endoplasmic reticulum-associated protein degradation (ERAD) to counteract the unfolding, damage, or misassembly of nuclear envelope proteins and ensure the integrity of the nuclear envelope membranes. Moreover, cells have the capacity to recognize and triage defective nuclear pore complexes to prevent their inheritance and preserve the longevity of progeny. These mechanisms serve to highlight the diverse strategies used by cells to maintain nuclear compartmentalization; we suggest they mitigate the progression and severity of diseases associated with nuclear envelope malfunction such as the laminopathies.
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73
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Abstract
The ESCRT proteins are an ancient system that buds membranes and severs membrane necks from their inner face. Three "classical" functions of the ESCRTs have dominated research into these proteins since their discovery in 2001: the biogenesis of multivesicular bodies in endolysosomal sorting; the budding of HIV-1 and other viruses from the plasma membrane of infected cells; and the membrane abscission step in cytokinesis. The past few years have seen an explosion of novel functions: the biogenesis of microvesicles and exosomes; plasma membrane wound repair; neuron pruning; extraction of defective nuclear pore complexes; nuclear envelope reformation; plus-stranded RNA virus replication compartment formation; and micro- and macroautophagy. Most, and perhaps all, of the functions involve the conserved membrane-neck-directed activities of the ESCRTs, revealing a remarkably widespread role for this machinery through a broad swath of cell biology.
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Affiliation(s)
- James H Hurley
- Department of Molecular and Cell Biology and California Institute for Quantitative Biosciences, University of California, Berkeley, Berkeley, CA, USA Life Sciences Division, Lawrence Berkeley National Lab, Berkeley, CA, USA
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