Browse
Submit Data
Databases
API
Help

Dataset Information

28 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Human ESCRT-III and VPS4 proteins are required for centrosome and spindle maintenance.

ABSTRACT: The ESCRT pathway helps mediate the final abscission step of cytokinesis in mammals and archaea. In mammals, two early acting proteins of the ESCRT pathway, ALIX and TSG101, are recruited to the midbody through direct interactions with the phosphoprotein CEP55. CEP55 resides at the centrosome through most of the cell cycle but then migrates to the midbody at the start of cytokinesis, suggesting that the ESCRT pathway may also have centrosomal links. Here, we have systematically analyzed the requirements for late-acting mammalian ESCRT-III and VPS4 proteins at different stages of mitosis and cell division. We found that depletion of VPS4A, VPS4B, or any of the 11 different human ESCRT-III (CHMP) proteins inhibited abscission. Remarkably, depletion of individual ESCRT-III and VPS4 proteins also altered centrosome and spindle pole numbers, producing multipolar spindles (most ESCRT-III/VPS4 proteins) or monopolar spindles (CHMP2A or CHMP5) and causing defects in chromosome segregation and nuclear morphology. VPS4 proteins concentrated at spindle poles during mitosis and then at midbodies during cytokinesis, implying that these proteins function directly at both sites. We conclude that ESCRT-III/VPS4 proteins function at centrosomes to help regulate their maintenance or proliferation and then at midbodies during abscission, thereby helping ensure the ordered progression through the different stages of cell division.

SUBMITTER: Morita E

PROVIDER: S-EPMC2919903 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Asymmetric ring structure of Vps4 required for ESCRT-III disassembly.

Project description: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.

| S-EPMC4686814 | biostudies-literature

ESCRT-III/Vps4 Controls Heterochromatin-Nuclear Envelope Attachments.

Project description:Eukaryotic genomes are organized within the nucleus through interactions with inner nuclear membrane (INM) proteins. How chromatin tethering to the INM is controlled in interphase and how this process contributes to subsequent mitotic nuclear envelope (NE) remodeling remains unclear. We have probed these fundamental questions using the fission yeast Schizosaccharomyces japonicus, which breaks and reforms the NE during mitosis. We show that attachments between heterochromatin and the transmembrane Lem2-Nur1 complex at the INM are remodeled in interphase by the ESCRT-III/Vps4 machinery. Failure of ESCRT-III/Vps4 to release Lem2-Nur1 from heterochromatin leads to persistent association of chromosomes with the INM throughout mitosis. At mitotic exit, such trapping of Lem2-Nur1 on heterochromatin prevents it from re-establishing nucleocytoplasmic compartmentalization. Our work identifies the Lem2-Nur1 complex as a substrate for the nuclear ESCRT machinery and explains how the dynamic tethering of chromosomes to the INM is linked to the establishment of nuclear compartmentalization.

| S-EPMC7139201 | biostudies-literature

Helical structures of ESCRT-III are disassembled by VPS4.

Project description:During intracellular membrane trafficking and remodeling, protein complexes known as the ESCRTs (endosomal sorting complexes required for transport) interact with membranes and are required for budding processes directed away from the cytosol, including the budding of intralumenal vesicles to form multivesicular bodies; for the budding of some enveloped viruses; and for daughter cell scission in cytokinesis. We found that the ESCRT-III proteins CHMP2A and CHMP3 (charged multivesicular body proteins 2A and 3) could assemble in vitro into helical tubular structures that expose their membrane interaction sites on the outside of the tubule, whereas the AAA-type adenosine triphosphatase VPS4 could bind on the inside of the tubule and disassemble the tubes upon adenosine triphosphate hydrolysis. CHMP2A and CHMP3 copolymerized in solution, and their membrane targeting was cooperatively enhanced on planar lipid bilayers. Such helical CHMP structures could thus assemble within the neck of an inwardly budding vesicle, catalyzing late steps in budding under the control of VPS4.

| S-EPMC2758909 | biostudies-literature

Assembly of the AAA ATPase Vps4 on ESCRT-III.

Project description:Vps4 is a key enzyme that functions in endosomal protein trafficking, cytokinesis, and retroviral budding. Vps4 activity is regulated by its recruitment from the cytoplasm to ESCRT-III, where the protein oligomerizes into an active ATPase. The recruitment and oligomerization steps are mediated by a complex network of at least 12 distinct interactions between Vps4, ESCRT-III, Ist1, Vta1, and Did2. The order of events leading to active, ESCRT-III-associated Vps4 is poorly understood. In this study we present a systematic in vivo analysis of the Vps4 interaction network. The data demonstrated a high degree of redundancy in the network. Although no single interaction was found to be essential for the localization or activity of Vps4, certain interactions proved more important than others. The most significant among these were the binding of Vps4 to Vta1 and to the ESCRT-III subunits Vps2 and Snf7. In our model we propose the formation of a recruitment complex in the cytoplasm that is composed of Did2-Ist1-Vps4, which upon binding to ESCRT-III recruits Vta1. Vta1 in turn is predicted to cause a rearrangement of the Vps4 interactions that initiates the assembly of the active Vps4 oligomer.

| S-EPMC2836958 | biostudies-literature

VPS4 triggers constriction and cleavage of ESCRT-III helical filaments.

Project description:Many cellular processes such as endosomal vesicle budding, virus budding, and cytokinesis require extensive membrane remodeling by the endosomal sorting complex required for transport III (ESCRT-III). ESCRT-III protein family members form spirals with variable diameters in vitro and in vivo inside tubular membrane structures, which need to be constricted to proceed to membrane fission. Here, we show, using high-speed atomic force microscopy and electron microscopy, that the AAA-type adenosine triphosphatase VPS4 constricts and cleaves ESCRT-III CHMP2A-CHMP3 helical filaments in vitro. Constriction starts asymmetrically and progressively decreases the diameter of CHMP2A-CHMP3 tubular structure, thereby coiling up the CHMP2A-CHMP3 filaments into dome-like end caps. Our results demonstrate that VPS4 actively constricts ESCRT-III filaments and cleaves them before their complete disassembly. We propose that the formation of ESCRT-III dome-like end caps by VPS4 within a membrane neck structure constricts the membrane to set the stage for membrane fission.

| S-EPMC6457934 | biostudies-literature

Did2 coordinates Vps4-mediated dissociation of ESCRT-III from endosomes.

Project description:The sorting of transmembrane cargo proteins into the lumenal vesicles of multivesicular bodies (MVBs) depends on the recruitment of endosomal sorting complexes required for transport (ESCRTs) to the cytosolic face of endosomal membranes. The subsequent dissociation of ESCRT complexes from endosomes requires Vps4, a member of the AAA family of adenosine triphosphatases. We show that Did2 directs Vps4 activity to the dissociation of ESCRT-III but has no role in the dissociation of ESCRT-I or -II. Surprisingly, vesicle budding into the endosome lumen occurs in the absence of Did2 function even though Did2 is required for the efficient sorting of MVB cargo proteins into lumenal vesicles. This uncoupling of MVB cargo sorting and lumenal vesicle formation suggests that the Vps4-mediated dissociation of ESCRT-III is an essential step in the sorting of cargo proteins into MVB vesicles but is not a prerequisite for the budding of vesicles into the endosome lumen.

| S-EPMC2064671 | biostudies-literature

Surveillance of nuclear pore complex assembly by ESCRT-III/Vps4.

Project description:The maintenance of nuclear compartmentalization by the nuclear envelope and nuclear pore complexes (NPCs) is essential for cell function; loss of compartmentalization is associated with cancers, laminopathies, and aging. We uncovered a pathway that surveils NPC assembly intermediates to promote the formation of functional NPCs. Surveillance is mediated by Heh2, a member of the LEM (Lap2-emerin-MAN1) family of integral inner nuclear membrane proteins, which binds to an early NPC assembly intermediate, but not to mature NPCs. Heh2 recruits the endosomal sorting complex required for transport (ESCRT)-III subunit Snf7 and the AAA-ATPase Vps4 to destabilize and clear defective NPC assembly intermediates. When surveillance or clearance is compromised, malformed NPCs accumulate in a storage of improperly assembled nuclear pore complexes compartment, or SINC. The SINC is retained in old mothers to prevent loss of daughter lifespan, highlighting a continuum of mechanisms to ensure nuclear compartmentalization.

| S-EPMC4194032 | biostudies-literature

Structural role of the Vps4-Vta1 interface in ESCRT-III recycling.

Project description:The ESCRT complexes are required for multivesicular body biogenesis, macroautophagy, cytokinesis, and the budding of HIV-1. The final step in the ESCRT cycle is the disassembly of the ESCRT-III lattice by the AAA+ ATPase Vps4. Vps4 assembles on its membrane-bound ESCRT-III substrate with its cofactor, Vta1. The crystal structure of the dimeric VSL domain of yeast Vta1 with the small ATPase and the betadomains of Vps4 was determined. Residues involved in structural interactions are conserved and are required for binding in vitro and for Cps1 sorting in vivo. Modeling of the Vta1 complex in complex with the lower hexameric ring of Vps4 indicates that the two-fold axis of the Vta1 VSL domain is parallel to within approximately 20 degrees of the six-fold axis of the hexamer. This suggests that Vta1 might not crosslink the two hexameric rings of Vps4, but rather stabilizes an array of Vps4-Vta1 complexes for ESCRT-III disassembly.

| S-EPMC3124813 | biostudies-literature

ATP-dependent force generation and membrane scission by ESCRT-III and Vps4.

Project description:The endosomal sorting complexes required for transport (ESCRTs) catalyze reverse-topology scission from the inner face of membrane necks in HIV budding, multivesicular endosome biogenesis, cytokinesis, and other pathways. We encapsulated ESCRT-III subunits Snf7, Vps24, and Vps2 and the AAA+ ATPase (adenosine triphosphatase) Vps4 in giant vesicles from which membrane nanotubes reflecting the correct topology of scission could be pulled. Upon ATP release by photo-uncaging, this system generated forces within the nanotubes that led to membrane scission in a manner dependent upon Vps4 catalytic activity and Vps4 coupling to the ESCRT-III proteins. Imaging of scission revealed Snf7 and Vps4 puncta within nanotubes whose presence followed ATP release, correlated with force generation and nanotube constriction, and preceded scission. These observations directly verify long-standing predictions that ATP-hydrolyzing assemblies of ESCRT-III and Vps4 sever membranes.

| S-EPMC6309985 | biostudies-literature

Vps4 disassembles an ESCRT-III filament by global unfolding and processive translocation.

Project description:The AAA+ ATPase Vps4 disassembles ESCRT-III and is essential for HIV-1 budding and other pathways. Vps4 is a paradigmatic member of a class of hexameric AAA+ ATPases that disassemble protein complexes without degradation. To distinguish between local displacement versus global unfolding mechanisms for complex disassembly, we carried out hydrogen/deuterium exchange during Saccharomyces cerevisiae Vps4 disassembly of a chimeric Vps24-2 ESCRT-III filament. EX1 exchange behavior shows that Vps4 completely unfolds ESCRT-III substrates on a time scale consistent with the disassembly reaction. The established unfoldase ClpX showed the same pattern, thus demonstrating a common unfolding mechanism. Vps4 hexamers containing a single cysteine residue in the pore loops were cross-linked to ESCRT-III subunits containing unique cysteines within the folded core domain. These data support a mechanism in which Vps4 disassembles its substrates by completely unfolding them and threading them through the central pore.

| S-EPMC4456219 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data