scholarly journals The VPS-20 subunit of the endosomal sorting complex ESCRT-III exhibits an open conformation in the absence of upstream activation

2015 ◽  
Vol 466 (3) ◽  
pp. 625-637 ◽  
Author(s):  
Amber L. Schuh ◽  
Michael Hanna ◽  
Kyle Quinney ◽  
Lei Wang ◽  
Ali Sarkeshik ◽  
...  
Keyword(s):  
Membrane Repair ◽  
Endosomal Sorting ◽  
Escrt Machinery ◽  
Cell Extracts ◽  
Open Conformation ◽  
Membrane Reorganization ◽  
Plasma Membrane Repair ◽  
Retroviral Budding ◽  
Vacuolar Protein

Members of the endosomal sorting complex required for transport (ESCRT) machinery function in membrane remodelling processes during multivesicular endosome (MVE) biogenesis, cytokinesis, retroviral budding and plasma membrane repair. During luminal vesicle formation at endosomes, the ESCRT-II complex and the ESCRT-III subunit vacuolar protein sorting (VPS)-20 play a specific role in regulating assembly of ESCRT-III filaments, which promote vesicle scission. Previous work suggests that Vps20 isoforms, like other ESCRT-III subunits, exhibits an auto-inhibited closed conformation in solution and its activation depends on an association with ESCRT-II specifically at membranes [1]. However, we show in the present study that Caenorhabditis elegans ESCRT-II and VPS-20 interact directly in solution, both in cytosolic cell extracts and in using recombinant proteins in vitro. Moreover, we demonstrate that purified VPS-20 exhibits an open extended conformation, irrespective of ESCRT-II binding, in contrast with the closed auto-inhibited architecture of another ESCRT-III subunit, VPS-24. Our data argue that individual ESCRT-III subunits adopt distinct conformations, which are tailored for their specific functions during ESCRT-mediated membrane reorganization events.

Growing functions of the ESCRT machinery in cell biology and viral replication

2017 ◽  
Vol 45 (3) ◽  
pp. 613-634 ◽  
Author(s):  
Edward J. Scourfield ◽  
Juan Martin-Serrano
Keyword(s):  
Cell Biology ◽  
Modular System ◽  
Membrane Repair ◽  
Endosomal Sorting ◽  
Cellular Processes ◽  
Functional Connections ◽  
Escrt Machinery ◽  
Viral Budding ◽  
Spatiotemporal Regulation ◽  
Plasma Membrane Repair

The vast expansion in recent years of the cellular processes promoted by the endosomal sorting complex required for transport (ESCRT) machinery has reinforced its identity as a modular system that uses multiple adaptors to recruit the core membrane remodelling activity at different intracellular sites and facilitate membrane scission. Functional connections to processes such as the aurora B-dependent abscission checkpoint also highlight the importance of the spatiotemporal regulation of the ESCRT machinery. Here, we summarise the role of ESCRTs in viral budding, and what we have learned about the ESCRT pathway from studying this process. These advances are discussed in the context of areas of cell biology that have been transformed by research in the ESCRT field, including cytokinetic abscission, nuclear envelope resealing and plasma membrane repair.

Structure and function of ESCRT-III

2009 ◽  
Vol 37 (1) ◽  
pp. 156-160 ◽  
Author(s):  
Suman Lata ◽  
Guy Schoehn ◽  
Julianna Solomons ◽  
Ricardo Pires ◽  
Heinrich G. Göttlinger ◽  
...  
Keyword(s):  
Multivesicular Body ◽  
Multivesicular Bodies ◽  
Tubular Structures ◽  
Body Protein ◽  
Enveloped Viruses ◽  
Endosomal Sorting ◽  
Vacuolar Protein ◽  
And Function ◽  
Endosomal Vesicles

ESCRT-III (endosomal sorting complex required for transport III) is required for the formation and abscission of intraluminal endosomal vesicles, which gives rise to multivesicular bodies, budding of some enveloped viruses and cytokinesis. ESCRT-III is composed of 11 members in humans, which, except for one, correspond to the six ESCRT-III-like proteins in yeast. At least CHMP (charged multivesicular body protein) 2A and CHMP3 assemble into helical tubular structures that provide a platform for membrane interaction and VPS (vacuolar protein sorting) 4-catalysed effects leading to disassembly of ESCRT-III CHMP2A–CHMP3 polymers in vitro. Progress towards the understanding of the structures and function of ESCRT-III, its activation, its regulation by accessory factors and its role in abscission of membrane enveloped structures in concert with VPS4 are discussed.

scholarly journals Efficient Cargo Sorting by ESCRT-I and the Subsequent Release of ESCRT-I from Multivesicular Bodies Requires the Subunit Mvb12

2007 ◽  
Vol 18 (2) ◽  
pp. 636-645 ◽  
Author(s):  
Matt Curtiss ◽  
Charles Jones ◽  
Markus Babst
Keyword(s):  
Protein Complex ◽  
Transmembrane Proteins ◽  
Multivesicular Body ◽  
Multivesicular Bodies ◽  
Rapid Degradation ◽  
Endosomal Sorting ◽  
Escrt Machinery ◽  
Complex Functions ◽  
Vacuolar Protein ◽  
Cargo Sorting

The endosomal sorting complex required for transport (ESCRT)-I protein complex functions in recognition and sorting of ubiquitinated transmembrane proteins into multivesicular body (MVB) vesicles. It has been shown that ESCRT-I contains the vacuolar protein sorting (Vps) proteins Vps23, Vps28, and Vps37. We identified an additional subunit of yeast ESCRT-I called Mvb12, which seems to associate with ESCRT-I by binding to Vps37. Transient recruitment of ESCRT-I to MVBs results in the rapid degradation of Mvb12. In contrast to mutations in other ESCRT-I subunits, which result in strong defects in MVB cargo sorting, deletion of MVB12 resulted in only a partial sorting phenotype. This trafficking defect was fully suppressed by overexpression of the ESCRT-II complex. Mutations in MVB12 did not affect recruitment of ESCRT-I to MVBs, but they did result in delivery of ESCRT-I to the vacuolar lumen via the MVB pathway. Together, these observations suggest that Mvb12 may function in regulating the interactions of ESCRT-I with cargo and other proteins of the ESCRT machinery to efficiently coordinate cargo sorting and release of ESCRT-I from the MVB.

scholarly journals ESCRT-dependent membrane repair negatively regulates pyroptosis downstream of GSDMD activation

Science ◽  
2018 ◽  
Vol 362 (6417) ◽  
pp. 956-960 ◽  
Author(s):  
Sebastian Rühl ◽  
Kateryna Shkarina ◽  
Benjamin Demarco ◽  
Rosalie Heilig ◽  
José Carlos Santos ◽  
...  
Keyword(s):  
Calcium Influx ◽  
Inflammasome Activation ◽  
Membrane Repair ◽  
Cellular Survival ◽  
Endosomal Sorting ◽  
Membrane Pores ◽  
Escrt Machinery ◽  
Inflammatory Caspases ◽  
Survival Mechanisms ◽  
Insight Into

Pyroptosis is a lytic form of cell death that is induced by inflammatory caspases upon activation of the canonical or noncanonical inflammasome pathways. These caspases cleave gasdermin D (GSDMD) to generate an N-terminal GSDMD fragment, which executes pyroptosis by forming membrane pores. We found that calcium influx through GSDMD pores serves as a signal for cells to initiate membrane repair by recruiting the endosomal sorting complexes required for transport (ESCRT) machinery to damaged membrane areas, such as the plasma membrane. Inhibition of the ESCRT-III machinery strongly enhances pyroptosis and interleukin-1β release in both human and murine cells after canonical or noncanonical inflammasome activation. These results not only attribute an anti-inflammatory role to membrane repair by the ESCRT-III system but also provide insight into general cellular survival mechanisms during pyroptosis.

ESCRT Machinery Is Required for Plasma Membrane Repair

Science ◽  
2014 ◽  
Vol 343 (6174) ◽  
pp. 1247136-1247136 ◽  
Author(s):  
A. J. Jimenez ◽  
P. Maiuri ◽  
J. Lafaurie-Janvore ◽  
S. Divoux ◽  
M. Piel ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Repair ◽  
Escrt Machinery ◽  
Plasma Membrane Repair

scholarly journals Dual roles of an Arabidopsis ESCRT component FREE1 in regulating vacuolar protein transport and autophagic degradation

2015 ◽  
Vol 112 (6) ◽  
pp. 1886-1891 ◽  
Author(s):  
Caiji Gao ◽  
Xiaohong Zhuang ◽  
Yong Cui ◽  
Xi Fu ◽  
Yilin He ◽  
...  
Keyword(s):  
Protein Trafficking ◽  
Protein Transport ◽  
Multivesicular Body ◽  
Organelle Biogenesis ◽  
Functional Roles ◽  
Endosomal Sorting ◽  
Escrt Machinery ◽  
Autophagic Degradation ◽  
Vacuolar Protein ◽  
Vacuole Biogenesis

Protein turnover can be achieved via the lysosome/vacuole and the autophagic degradation pathways. Evidence has accumulated revealing that efficient autophagic degradation requires functional endosomal sorting complex required for transport (ESCRT) machinery. However, the interplay between the ESCRT machinery and the autophagy regulator remains unclear. Here, we show that FYVE domain protein required for endosomal sorting 1 (FREE1), a recently identified plant-specific ESCRT component essential for multivesicular body (MVB) biogenesis and plant growth, plays roles both in vacuolar protein transport and autophagic degradation. FREE1 also regulates vacuole biogenesis in both seeds and vegetative cells of Arabidopsis. Additionally, FREE1 interacts directly with a unique plant autophagy regulator SH3 DOMAIN-CONTAINING PROTEIN2 and associates with the PI3K complex, to regulate the autophagic degradation in plants. Thus, FREE1 plays multiple functional roles in vacuolar protein trafficking and organelle biogenesis as well as in autophagic degradation via a previously unidentified regulatory mechanism of cross-talk between the ESCRT machinery and autophagy process.

scholarly journals The ESCRTs – converging on mechanism

2020 ◽  
Vol 133 (18) ◽  
pp. jcs240333 ◽  
Author(s):  
Mark Remec Pavlin ◽  
James H. Hurley
Keyword(s):  
Associated Factors ◽  
Multivesicular Body ◽  
Underlying Mechanism ◽  
Complex Nature ◽  
Mechanistic Studies ◽  
Membrane Repair ◽  
Helical Structures ◽  
Endosomal Sorting ◽  
Geometric Transitions

ABSTRACTThe endosomal sorting complexes required for transport (ESCRTs) I, -II and –III, and their associated factors are a collection of ∼20 proteins in yeast and ∼30 in mammals, responsible for severing membrane necks in processes that range from multivesicular body formation, HIV release and cytokinesis, to plasma and lysosomal membrane repair. ESCRTs are best known for ‘reverse-topology’ membrane scission, where they act on the inner surface of membrane necks, often when membranes are budded away from the cytosol. These events are driven by membrane-associated assemblies of dozens to hundreds of ESCRT molecules. ESCRT-III proteins form filaments with a variety of geometries and ESCRT-I has now been shown to also form helical structures. The complex nature of the system and the unusual topology of its action has made progress challenging, and led to controversies with regard to its underlying mechanism. This Review will focus on recent advances obtained by structural in vitro reconstitution and in silico mechanistic studies, and places them in their biological context. The field is converging towards a consensus on the broad outlines of a mechanism that is driven by a progressive ATP-dependent treadmilling exchange of ESCRT subunits, as well as compositional change and geometric transitions in ESCRT filaments.

scholarly journals New component of ESCRT-I regulates endosomal sorting complex assembly

2006 ◽  
Vol 175 (5) ◽  
pp. 815-823 ◽  
Author(s):  
Tony Chu ◽  
Ji Sun ◽  
Suraj Saksena ◽  
Scott D. Emr
Keyword(s):  
Molecular Mechanisms ◽  
Critical Role ◽  
Coiled Coil ◽  
Multivesicular Body ◽  
Stable Complex ◽  
Oligomeric State ◽  
Endosomal Sorting ◽  
Coiled Coil Domain ◽  
Retroviral Budding ◽  
Vacuolar Protein

The endosomal sorting complex required for transport (ESCRT) complexes play a critical role in receptor down-regulation and retroviral budding. Although the crystal structures of two ESCRT complexes have been determined, the molecular mechanisms underlying the assembly and regulation of the ESCRT machinery are still poorly understood. We identify a new component of the ESCRT-I complex, multivesicular body sorting factor of 12 kD (Mvb12), and demonstrate that Mvb12 binds to the coiled-coil domain of the ESCRT-I subunit vacuolar protein sorting 23 (Vps23). We show that ESCRT-I adopts an oligomeric state in the cytosol, the formation of which requires the coiled-coil domain of Vps23, as well as Mvb12. Loss of Mvb12 results in the disassembly of the ESCRT-I oligomer and the formation of a stable complex of ESCRT-I and -II in the cytosol. We propose that Mvb12 stabilizes ESCRT-I in an oligomeric, inactive state in the cytosol to ensure that the ordered recruitment and assembly of ESCRT-I and -II is spatially and temporally restricted to the surface of the endosome after activation of the MVB sorting reaction.

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