scholarly journals TANK-Binding Kinase 1 Attenuates PTAP-Dependent Retroviral Budding through Targeting Endosomal Sorting Complex Required for Transport-I

2011 ◽  
Vol 186 (5) ◽  
pp. 3023-3030 ◽  
Author(s):  
Qi Da ◽  
Xuanming Yang ◽  
Youli Xu ◽  
Guangxia Gao ◽  
Genhong Cheng ◽  
...  
Keyword(s):  
Endosomal Sorting ◽  
Retroviral Budding

ESCRTs and human disease

2009 ◽  
Vol 37 (1) ◽  
pp. 167-172 ◽  
Author(s):  
Suraj Saksena ◽  
Scott D. Emr
Keyword(s):  
Human Disease ◽  
Protein Sorting ◽  
Critical Role ◽  
Multivesicular Body ◽  
Human Diseases ◽  
Down Regulation ◽  
Endosomal Sorting ◽  
Retroviral Budding

The ESCRT (endosomal sorting complex required for transport) machinery plays a critical role in receptor down-regulation, retroviral budding, and other normal and pathological processes. The ESCRT components are conserved in all five major subgroups of eukaryotes. This review summarizes the growing number of links identified between ESCRT-mediated protein sorting in the MVB (multivesicular body) pathway and various human diseases.

scholarly journals When in Need of an ESCRT: The Nature of Virus Assembly Sites Suggests Mechanistic Parallels between Nuclear Virus Egress and Retroviral Budding

Viruses ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1138
Author(s):  
Kevin M. Rose
Keyword(s):  
Virus Assembly ◽  
Cellular Membrane ◽  
Particle Assembly ◽  
Endosomal Sorting ◽  
Nuclear Egress ◽  
Viral Particles ◽  
Nuclear Particle ◽  
Retroviral Budding ◽  
Cellular Compartments ◽  
Hsv 1

The proper assembly and dissemination of progeny virions is a fundamental step in virus replication. As a whole, viruses have evolved a myriad of strategies to exploit cellular compartments and mechanisms to ensure a successful round of infection. For enveloped viruses such as retroviruses and herpesviruses, acquisition and incorporation of cellular membrane is an essential process during the formation of infectious viral particles. To do this, these viruses have evolved to hijack the host Endosomal Sorting Complexes Required for Transport (ESCRT-I, -II, and -III) to coordinate the sculpting of cellular membrane at virus assembly and dissemination sites, in seemingly different, yet fundamentally similar ways. For instance, at the plasma membrane, ESCRT-I recruitment is essential for HIV-1 assembly and budding, while it is dispensable for the release of HSV-1. Further, HSV-1 was shown to recruit ESCRT-III for nuclear particle assembly and egress, a process not used by retroviruses during replication. Although the cooption of ESCRTs occurs in two separate subcellular compartments and at two distinct steps for these viral lifecycles, the role fulfilled by ESCRTs at these sites appears to be conserved. This review discusses recent findings that shed some light on the potential parallels between retroviral budding and nuclear egress and proposes a model where HSV-1 nuclear egress may occur through an ESCRT-dependent mechanism.

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.

scholarly journals Structural analysis and modeling reveals new mechanisms governing ESCRT-III spiral filament assembly

2014 ◽  
Vol 206 (6) ◽  
pp. 763-777 ◽  
Author(s):  
Qing-Tao Shen ◽  
Amber L. Schuh ◽  
Yuqing Zheng ◽  
Kyle Quinney ◽  
Lei Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Lipid Bilayers ◽  
Protein Complexes ◽  
Carboxyl Terminus ◽  
Two Dimensional ◽  
Membrane Remodeling ◽  
Endosomal Sorting ◽  
Filament Assembly ◽  
Retroviral Budding ◽  
Dynamics Simulations

The scission of biological membranes is facilitated by a variety of protein complexes that bind and manipulate lipid bilayers. ESCRT-III (endosomal sorting complex required for transport III) filaments mediate membrane scission during the ostensibly disparate processes of multivesicular endosome biogenesis, cytokinesis, and retroviral budding. However, mechanisms by which ESCRT-III subunits assemble into a polymer remain unknown. Using cryogenic electron microscopy (cryo-EM), we found that the full-length ESCRT-III subunit Vps32/CHMP4B spontaneously forms single-stranded spiral filaments. The resolution afforded by two-dimensional cryo-EM combined with molecular dynamics simulations revealed that individual Vps32/CHMP4B monomers within a filament are flexible and able to accommodate a range of bending angles. In contrast, the interface between monomers is stable and refractory to changes in conformation. We additionally found that the carboxyl terminus of Vps32/CHMP4B plays a key role in restricting the lateral association of filaments. Our findings highlight new mechanisms by which ESCRT-III filaments assemble to generate a unique polymer capable of membrane remodeling in multiple cellular contexts.

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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