scholarly journals ULK3 regulates cytokinetic abscission by phosphorylating ESCRT-III proteins

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Anna Caballe ◽  
Dawn M Wenzel ◽  
Monica Agromayor ◽  
Steven L Alam ◽  
Jack J Skalicky ◽  
...  
Keyword(s):  
Nuclear Pore ◽  
Aurora B ◽  
Physical Separation ◽  
Protection Mechanism ◽  
Endosomal Sorting ◽  
Daughter Cells ◽  
Escrt Machinery ◽  
A Genome ◽  
Biochemical Studies ◽  
Genome Protection

The endosomal sorting complexes required for transport (ESCRT) machinery mediates the physical separation between daughter cells during cytokinetic abscission. This process is regulated by the abscission checkpoint, a genome protection mechanism that relies on Aurora B and the ESCRT-III subunit CHMP4C to delay abscission in response to chromosome missegregation. In this study, we show that Unc-51-like kinase 3 (ULK3) phosphorylates and binds ESCRT-III subunits via tandem MIT domains, and thereby, delays abscission in response to lagging chromosomes, nuclear pore defects, and tension forces at the midbody. Our structural and biochemical studies reveal an unusually tight interaction between ULK3 and IST1, an ESCRT-III subunit required for abscission. We also demonstrate that IST1 phosphorylation by ULK3 is an essential signal required to sustain the abscission checkpoint and that ULK3 and CHMP4C are functionally linked components of the timer that controls abscission in multiple physiological situations.

scholarly journals The Abscission Checkpoint: A Guardian of Chromosomal Stability

Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3350
Author(s):  
Eleni Petsalaki ◽  
George Zachos
Keyword(s):  
Mammalian Cells ◽  
Kinase Activity ◽  
Nuclear Pore ◽  
Aurora B ◽  
Intercellular Bridge ◽  
Endosomal Sorting ◽  
Daughter Cells ◽  
Chromosomal Passenger ◽  
Dividing Cells ◽  
Chromatin Bridges

The abscission checkpoint contributes to the fidelity of chromosome segregation by delaying completion of cytokinesis (abscission) when there is chromatin lagging in the intercellular bridge between dividing cells. Although additional triggers of an abscission checkpoint-delay have been described, including nuclear pore defects, replication stress or high intercellular bridge tension, this review will focus only on chromatin bridges. In the presence of such abnormal chromosomal tethers in mammalian cells, the abscission checkpoint requires proper localization and optimal kinase activity of the Chromosomal Passenger Complex (CPC)-catalytic subunit Aurora B at the midbody and culminates in the inhibition of Endosomal Sorting Complex Required for Transport-III (ESCRT-III) components at the abscission site to delay the final cut. Furthermore, cells with an active checkpoint stabilize the narrow cytoplasmic canal that connects the two daughter cells until the chromatin bridges are resolved. Unsuccessful resolution of chromatin bridges in checkpoint-deficient cells or in cells with unstable intercellular canals can lead to chromatin bridge breakage or tetraploidization by regression of the cleavage furrow. In turn, these outcomes can lead to accumulation of DNA damage, chromothripsis, generation of hypermutation clusters and chromosomal instability, which are associated with cancer formation or progression. Recently, many important questions regarding the mechanisms of the abscission checkpoint have been investigated, such as how the presence of chromatin bridges is signaled to the CPC, how Aurora B localization and kinase activity is regulated in late midbodies, the signaling pathways by which Aurora B implements the abscission delay, and how the actin cytoskeleton is remodeled to stabilize intercellular canals with DNA bridges. Here, we review recent progress toward understanding the mechanisms of the abscission checkpoint and its role in guarding genome integrity at the chromosome level, and consider its potential implications for cancer therapy.

scholarly journals VPS37A directs ESCRT recruitment for phagophore closure

2019 ◽  
Vol 218 (10) ◽  
pp. 3336-3354 ◽  
Author(s):  
Yoshinori Takahashi ◽  
Xinwen Liang ◽  
Tatsuya Hattori ◽  
Zhenyuan Tang ◽  
Haiyan He ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Growth Factor Receptor ◽  
Multivesicular Body ◽  
Regulatory Mechanisms ◽  
Endosomal Sorting ◽  
Aaa Atpase ◽  
Escrt Machinery ◽  
Genome Wide ◽  
A Genome ◽  
Epidermal Growth

The process of phagophore closure requires the endosomal sorting complex required for transport III (ESCRT-III) subunit CHMP2A and the AAA ATPase VPS4, but their regulatory mechanisms remain unknown. Here, we establish a FACS-based HaloTag-LC3 autophagosome completion assay to screen a genome-wide CRISPR library and identify the ESCRT-I subunit VPS37A as a critical component for phagophore closure. VPS37A localizes on the phagophore through the N-terminal putative ubiquitin E2 variant domain, which is found to be required for autophagosome completion but dispensable for ESCRT-I complex formation and the degradation of epidermal growth factor receptor in the multivesicular body pathway. Notably, loss of VPS37A abrogates the phagophore recruitment of the ESCRT-I subunit VPS28 and CHMP2A, whereas inhibition of membrane closure by CHMP2A depletion or VPS4 inhibition accumulates VPS37A on the phagophore. These observations suggest that VPS37A coordinates the recruitment of a unique set of ESCRT machinery components for phagophore closure in mammalian cells.

scholarly journals The chromosomal passenger complex controls the function of endosomal sorting complex required for transport-III Snf7 proteins during cytokinesis

Open Biology ◽  
2012 ◽  
Vol 2 (5) ◽  
pp. 120070 ◽  
Author(s):  
Luisa Capalbo ◽  
Emilie Montembault ◽  
Tetsuya Takeda ◽  
Zuni I. Bassi ◽  
David M. Glover ◽  
...  
Keyword(s):  
Cell Division ◽  
Molecular Basis ◽  
Cleavage Site ◽  
Human Cells ◽  
Membrane Association ◽  
Aurora B ◽  
Chromosomal Passenger Complex ◽  
Endosomal Sorting ◽  
Daughter Cells ◽  
Chromosomal Passenger

Summary Cytokinesis controls the proper segregation of nuclear and cytoplasmic materials at the end of cell division. The chromosomal passenger complex (CPC) has been proposed to monitor the final separation of the two daughter cells at the end of cytokinesis in order to prevent cell abscission in the presence of DNA at the cleavage site, but the precise molecular basis for this is unclear. Recent studies indicate that abscission could be mediated by the assembly of filaments comprising components of the endosomal sorting complex required for transport-III (ESCRT-III). Here, we show that the CPC subunit Borealin interacts directly with the Snf7 components of ESCRT-III in both Drosophila and human cells. Moreover, we find that the CPC's catalytic subunit, Aurora B kinase, phosphorylates one of the three human Snf7 paralogues—CHMP4C—in its C-terminal tail, a region known to regulate its ability to form polymers and associate with membranes. Phosphorylation at these sites appears essential for CHMP4C function because their mutation leads to cytokinesis defects. We propose that CPC controls abscission timing through inhibition of ESCRT-III Snf7 polymerization and membrane association using two concurrent mechanisms: interaction of its Borealin component with Snf7 proteins and phosphorylation of CHMP4C by Aurora B.

scholarly journals ATR and a Chk1-Aurora B pathway coordinate postmitotic genome surveillance with cytokinetic abscission

2015 ◽  
Vol 26 (12) ◽  
pp. 2217-2226 ◽  
Author(s):  
Douglas R. Mackay ◽  
Katharine S. Ullman
Keyword(s):  
Signaling Pathways ◽  
Replication Stress ◽  
Dna Lesions ◽  
Aurora B ◽  
Physical Separation ◽  
Daughter Cells ◽  
Cellular Events

Aurora B regulates cytokinesis timing and plays a central role in the abscission checkpoint. Cellular events monitored by this checkpoint are beginning to be elucidated, yet signaling pathways upstream of Aurora B in this context remain poorly understood. Here we reveal a new connection between postmitotic genome surveillance and cytokinetic abscission. Underreplicated DNA lesions are known to be transmitted through mitosis and protected in newly formed nuclei by recruitment of 53BP1 and other proteins until repair takes place. We find that this genome surveillance initiates before completion of cytokinesis. Elevating replication stress increases this postmitotic process and delays cytokinetic abscission by keeping the abscission checkpoint active. We further find that ATR activity in midbody-stage cells links postmitotic genome surveillance to abscission timing and that Chk1 integrates this and other signals upstream of Aurora B to regulate when the final step in the physical separation of daughter cells occurs.

scholarly journals The midbody ring scaffolds the abscission machinery in the absence of midbody microtubules

2013 ◽  
Vol 203 (3) ◽  
pp. 505-520 ◽  
Author(s):  
Rebecca A. Green ◽  
Jonathan R. Mayers ◽  
Shaohe Wang ◽  
Lindsay Lewellyn ◽  
Arshad Desai ◽  
...  
Keyword(s):  
Daughter Cell ◽  
Membrane Remodeling ◽  
Intercellular Bridge ◽  
Contractile Ring ◽  
Endosomal Sorting ◽  
Daughter Cells ◽  
Escrt Machinery ◽  
Two Stages ◽  
Inside Out

Abscission completes cytokinesis to form the two daughter cells. Although abscission could be organized from the inside out by the microtubule-based midbody or from the outside in by the contractile ring–derived midbody ring, it is assumed that midbody microtubules scaffold the abscission machinery. In this paper, we assess the contribution of midbody microtubules versus the midbody ring in the Caenorhabditis elegans embryo. We show that abscission occurs in two stages. First, the cytoplasm in the daughter cells becomes isolated, coincident with formation of the intercellular bridge; proper progression through this stage required the septins (a midbody ring component) but not the membrane-remodeling endosomal sorting complex required for transport (ESCRT) machinery. Second, the midbody and midbody ring are released into a specific daughter cell during the subsequent cell division; this stage required the septins and the ESCRT machinery. Surprisingly, midbody microtubules were dispensable for both stages. These results delineate distinct steps during abscission and highlight the central role of the midbody ring, rather than midbody microtubules, in their execution.

scholarly journals Membrane remodeling during embryonic abscission in Caenorhabditis elegans

2017 ◽  
Vol 216 (5) ◽  
pp. 1277-1286 ◽  
Author(s):  
Julia König ◽  
E.B. Frankel ◽  
Anjon Audhya ◽  
Thomas Müller-Reichert
Keyword(s):  
Caenorhabditis Elegans ◽  
Random Order ◽  
Membrane Remodeling ◽  
Time Resolved ◽  
Physical Separation ◽  
Endosomal Sorting ◽  
C Elegans ◽  
Daughter Cells ◽  
Membrane Scission ◽  
Late Stages

Abscission is the final step of cytokinesis and results in the physical separation of two daughter cells. In this study, we conducted a time-resolved series of electron tomographic reconstructions to define the steps required for the first embryonic abscission in Caenorhabditis elegans. Our findings indicate that membrane scission occurs on both sides of the midbody ring with random order and that completion of the scission process requires actomyosin-driven membrane remodeling, but not microtubules. Moreover, continuous membrane removal predominates during the late stages of cytokinesis, mediated by both dynamin and the ESCRT (endosomal sorting complex required for transport) machinery. Surprisingly, in the absence of ESCRT function in C. elegans, cytokinetic abscission is delayed but can be completed, suggesting the existence of parallel membrane-reorganizing pathways that cooperatively enable the efficient severing of cytoplasmic connections between dividing daughter cells.

scholarly journals ALIX and ESCRT-I/II function as parallel ESCRT-III recruiters in cytokinetic abscission

2016 ◽  
Vol 212 (5) ◽  
pp. 499-513 ◽  
Author(s):  
Liliane Christ ◽  
Eva M. Wenzel ◽  
Knut Liestøl ◽  
Camilla Raiborg ◽  
Coen Campsteijn ◽  
...  
Keyword(s):  
Cell Division ◽  
Final Stage ◽  
Binding Protein ◽  
Intercellular Bridge ◽  
Checkpoint Signaling ◽  
Endosomal Sorting ◽  
Daughter Cells ◽  
Escrt Machinery ◽  
Chromosome Bridges ◽  
In Cells

Cytokinetic abscission, the final stage of cell division where the two daughter cells are separated, is mediated by the endosomal sorting complex required for transport (ESCRT) machinery. The ESCRT-III subunit CHMP4B is a key effector in abscission, whereas its paralogue, CHMP4C, is a component in the abscission checkpoint that delays abscission until chromatin is cleared from the intercellular bridge. How recruitment of these components is mediated during cytokinesis remains poorly understood, although the ESCRT-binding protein ALIX has been implicated. Here, we show that ESCRT-II and the ESCRT-II–binding ESCRT-III subunit CHMP6 cooperate with ESCRT-I to recruit CHMP4B, with ALIX providing a parallel recruitment arm. In contrast to CHMP4B, we find that recruitment of CHMP4C relies predominantly on ALIX. Accordingly, ALIX depletion leads to furrow regression in cells with chromosome bridges, a phenotype associated with abscission checkpoint signaling failure. Collectively, our work reveals a two-pronged recruitment of ESCRT-III to the cytokinetic bridge and implicates ALIX in abscission checkpoint signaling.

The ESCRT machinery: a cellular apparatus for sorting and scission

2010 ◽  
Vol 38 (6) ◽  
pp. 1397-1412 ◽  
Author(s):  
Jeremy Carlton
Keyword(s):  
Protein Complexes ◽  
Multivesicular Bodies ◽  
Particle Assembly ◽  
Endosomal Sorting ◽  
Cellular Processes ◽  
Daughter Cells ◽  
Escrt Machinery ◽  
Membrane Fission

The ESCRT (endosomal sorting complex required for transport) machinery is a group of multisubunit protein complexes conserved across phyla that are involved in a range of diverse cellular processes. ESCRT proteins regulate the biogenesis of MVBs (multivesicular bodies) and the sorting of ubiquitinated cargos on to ILVs (intraluminal vesicles) within these MVBs. These proteins are also recruited to sites of retroviral particle assembly, where they provide an activity that allows release of these retroviruses. More recently, these proteins have been shown to be recruited to the intracellular bridge linking daughter cells at the end of mitosis, where they act to ensure the separation of these cells through the process of cytokinesis. Although these cellular processes are diverse, they share a requirement for a topologically unique membrane-fission step for their completion. Current models suggest that the ESCRT machinery catalyses this membrane fission.

scholarly journals AKTIP interacts with ESCRT I and is needed for the recruitment of ESCRT III subunits to the midbody

PLoS Genetics ◽  
2021 ◽  
Vol 17 (8) ◽  
pp. e1009757
Author(s):  
Chiara Merigliano ◽  
Romina Burla ◽  
Mattia La Torre ◽  
Simona Del Giudice ◽  
Hsiangling Teo ◽  
...  
Keyword(s):  
Nuclear Membrane ◽  
Present Evidence ◽  
Endosomal Sorting ◽  
Daughter Cells ◽  
Escrt Machinery ◽  
Close Proximity ◽  
Interphase Cells ◽  
Sequence Similarities

To complete mitosis, the bridge that links the two daughter cells needs to be cleaved. This step is carried out by the endosomal sorting complex required for transport (ESCRT) machinery. AKTIP, a protein discovered to be associated with telomeres and the nuclear membrane in interphase cells, shares sequence similarities with the ESCRT I component TSG101. Here we present evidence that during mitosis AKTIP is part of the ESCRT machinery at the midbody. AKTIP interacts with the ESCRT I subunit VPS28 and forms a circular supra-structure at the midbody, in close proximity with TSG101 and VPS28 and adjacent to the members of the ESCRT III module CHMP2A, CHMP4B and IST1. Mechanistically, the recruitment of AKTIP is dependent on MKLP1 and independent of CEP55. AKTIP and TSG101 are needed together for the recruitment of the ESCRT III subunit CHMP4B and in parallel for the recruitment of IST1. Alone, the reduction of AKTIP impinges on IST1 and causes multinucleation. Our data altogether reveal that AKTIP is a component of the ESCRT I module and functions in the recruitment of ESCRT III components required for abscission.

scholarly journals Defects in nuclear pore assembly lead to activation of an Aurora B–mediated abscission checkpoint

2010 ◽  
Vol 191 (5) ◽  
pp. 923-931 ◽  
Author(s):  
Douglas R. Mackay ◽  
Masaki Makise ◽  
Katharine S. Ullman
Keyword(s):  
Small Interfering Rna ◽  
Nuclear Pore ◽  
Aurora B ◽  
Nuclear Pore Complexes ◽  
Daughter Cells ◽  
Nuclear Environment ◽  
Genomic Regulation ◽  
Pore Complexes ◽  
Interfering Rna ◽  
Nuclear Pore Assembly

Correct assembly of nuclear pore complexes (NPCs), which directly and indirectly control nuclear environment and architecture, is vital to genomic regulation. We previously found that nucleoporin 153 (Nup153) is required for timely progression through late mitosis. In this study, we report that disruption of Nup153 function by either small interfering RNA–mediated depletion or expression of a dominant-interfering Nup153 fragment results in dramatic mistargeting of the pore basket components Tpr and Nup50 in midbody-stage cells. We find a concomitant appearance of aberrantly localized active Aurora B and an Aurora B–dependent delay in abscission. Depletion of Nup50 is also sufficient to increase the number of midbody-stage cells and, likewise, triggers distinctive mislocalization of Aurora B. Together, our results suggest that defects in nuclear pore assembly, and specifically the basket structure, at this time of the cell cycle activate an Aurora B–mediated abscission checkpoint, thereby ensuring that daughter cells are generated only when fully formed NPCs are present.

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