scholarly journals Direct role of dynein motor in stable kinetochore-microtubule attachment, orientation, and alignment

2008 ◽  
Vol 182 (6) ◽  
pp. 1045-1054 ◽  
Author(s):  
Dileep Varma ◽  
Pascale Monzo ◽  
Stephanie A. Stehman ◽  
Richard B. Vallee
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Cytoplasmic Dynein ◽  
Oscillatory Behavior ◽  
Supporting Evidence ◽  
Mitotic Spindles ◽  
Direct Role ◽  
Regulatory Factors ◽  
Microtubule Attachment ◽  
Dynein Motor ◽  
Show Evidence

Cytoplasmic dynein has been implicated in diverse mitotic functions, several involving its association with kinetochores. Much of the supporting evidence comes from inhibition of dynein regulatory factors. To obtain direct insight into kinetochore dynein function, we expressed a series of dynein tail fragments, which we find displace motor-containing dynein heavy chain (HC) from kinetochores without affecting other subunits, regulatory factors, or microtubule binding proteins. Cells with bipolar mitotic spindles progress to late prometaphase-metaphase at normal rates. However, the dynein tail, dynactin, Mad1, and BubR1 persist at the aligned kinetochores, which is consistent with a role for dynein in self-removal and spindle assembly checkpoint inactivation. Kinetochore pairs also show evidence of misorientation relative to the spindle equator and abnormal oscillatory behavior. Further, kinetochore microtubule bundles are severely destabilized at reduced temperatures. Dynein HC RNAi and injection of anti-dynein antibody in MG132-arrested metaphase cells produced similar effects. These results identify a novel function for the dynein motor in stable microtubule attachment and maintenance of kinetochore orientation during metaphase chromosome alignment.

scholarly journals Complex assembly, crystallization and preliminary X-ray crystallographic analysis of the human Rod–Zwilch–ZW10 (RZZ) complex

2015 ◽  
Vol 71 (4) ◽  
pp. 438-442 ◽  
Author(s):  
Anika Altenfeld ◽  
Sabine Wohlgemuth ◽  
Annemarie Wehenkel ◽  
Ingrid R. Vetter ◽  
Andrea Musacchio
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Insect Cells ◽  
Cytoplasmic Dynein ◽  
Crystallographic Analysis ◽  
Resolution Limit ◽  
Unit Cell Parameters ◽  
Natural Sources ◽  
X Ray ◽  
Cell Parameters ◽  
Microtubule Attachment

The spindle-assembly checkpoint (SAC) monitors kinetochore–microtubule attachment during mitosis. In metazoans, the three-subunit Rod–Zwilch–ZW10 (RZZ) complex is a crucial SAC component that interacts with additional SAC-activating and SAC-silencing components, including the Mad1–Mad2 complex and cytoplasmic dynein. The RZZ complex contains two copies of each subunit and has a predicted molecular mass of ∼800 kDa. Given the low abundance of the RZZ complex in natural sources, its recombinant reconstitution was attempted by co-expression of its subunits in insect cells. The RZZ complex was purified to homogeneity and subjected to systematic crystallization attempts. Initial crystals containing the entire RZZ complex were obtained using the sitting-drop method and were subjected to optimization to improve the diffraction resolution limit. The crystals belonged to space groupP31(No. 144) orP32(No. 145), with unit-cell parametersa=b= 215.45,c= 458.7 Å, α = β = 90.0, γ = 120.0°.

scholarly journals Spindly, a novel protein essential for silencing the spindle assembly checkpoint, recruits dynein to the kinetochore

2007 ◽  
Vol 177 (6) ◽  
pp. 1005-1015 ◽  
Author(s):  
Eric R. Griffis ◽  
Nico Stuurman ◽  
Ronald D. Vale
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Metaphase Plate ◽  
Spindle Assembly ◽  
Cytoplasmic Dynein ◽  
Checkpoint Proteins ◽  
Drosophila Melanogaster S2 Cells ◽  
Microtubule Attachment ◽  
Anaphase Onset ◽  
Cell Biol ◽  
Novel Protein

The eukaryotic spindle assembly checkpoint (SAC) monitors microtubule attachment to kinetochores and prevents anaphase onset until all kinetochores are aligned on the metaphase plate. In higher eukaryotes, cytoplasmic dynein is involved in silencing the SAC by removing the checkpoint proteins Mad2 and the Rod–Zw10–Zwilch complex (RZZ) from aligned kinetochores (Howell, B.J., B.F. McEwen, J.C. Canman, D.B. Hoffman, E.M. Farrar, C.L. Rieder, and E.D. Salmon. 2001. J. Cell Biol. 155:1159–1172; Wojcik, E., R. Basto, M. Serr, F. Scaerou, R. Karess, and T. Hays. 2001. Nat. Cell Biol. 3:1001–1007). Using a high throughput RNA interference screen in Drosophila melanogaster S2 cells, we have identified a new protein (Spindly) that accumulates on unattached kinetochores and is required for silencing the SAC. After the depletion of Spindly, dynein cannot target to kinetochores, and, as a result, cells arrest in metaphase with high levels of kinetochore-bound Mad2 and RZZ. We also identified a human homologue of Spindly that serves a similar function. However, dynein's nonkinetochore functions are unaffected by Spindly depletion. Our findings indicate that Spindly is a novel regulator of mitotic dynein, functioning specifically to target dynein to kinetochores.

scholarly journals Dynactin's pointed-end complex is a cargo-targeting module

2012 ◽  
Vol 23 (19) ◽  
pp. 3827-3837 ◽  
Author(s):  
Ting-Yu Yeh ◽  
Nicholas J. Quintyne ◽  
Brett R. Scipioni ◽  
D. Mark Eckley ◽  
Trina A. Schroer
Keyword(s):  
Cytoplasmic Dynein ◽  
Cross Linking ◽  
Structural Domain ◽  
Mitotic Spindles ◽  
Protein Overexpression ◽  
Recycling Endosome ◽  
Binding Partners ◽  
Dynein Motor ◽  
Pointed End ◽  
Chemical Cross Linking

Dynactin is an essential part of the cytoplasmic dynein motor that enhances motor processivity and serves as an adaptor that allows dynein to bind cargoes. Much is known about dynactin's interaction with dynein and microtubules, but how it associates with its diverse complement of subcellular binding partners remains mysterious. It has been suggested that cargo specification involves a group of subunits referred to as the “pointed-end complex.” We used chemical cross-linking, RNA interference, and protein overexpression to characterize interactions within the pointed-end complex and explore how it contributes to dynactin's interactions with endomembranes. The Arp11 subunit, which caps one end of dynactin's Arp1 filament, and p62, which binds Arp11 and Arp1, are necessary for dynactin stability. These subunits also allow dynactin to bind the nuclear envelope prior to mitosis. p27 and p25, by contrast, are peripheral components that can be removed without any obvious impact on dynactin integrity. Dynactin lacking these subunits shows reduced membrane binding. Depletion of p27 and p25 results in impaired early and recycling endosome movement, but late endosome movement is unaffected, and mitotic spindles appear normal. We conclude that the pointed-end complex is a bipartite structural domain that stabilizes dynactin and supports its binding to different subcellular structures.

scholarly journals Antagonism between the dynein and Ndc80 complexes at kinetochores controls the stability of kinetochore-microtubule attachments during mitosis

2018 ◽  
Author(s):  
Mohammed A. Amin ◽  
Richard J. McKenney ◽  
Dileep Varma
Keyword(s):  
Spindle Assembly Checkpoint ◽  
Protein Complexes ◽  
Molecular Motor ◽  
Cytoplasmic Dynein ◽  
C Elegans ◽  
Dynein Motor ◽  
Chromosome Alignment ◽  
Directed Motility ◽  
The Stability ◽  
Early Mitosis

AbstractChromosome alignment and segregation during mitosis depends critically on kinetochoremicrotubule (kMT) attachments that are mediated by the function of the molecular motor cytoplasmic dynein, and the kinetochore microtubule (MT) binding complex, Ndc80. The RZZ (Rod-ZW10-Zwilch) complex is central to this coordination as it has an important role in dynein recruitment and has recently been reported to have a key function in the regulation of stable kMT attachment formation in C. elegans. However, the mechanism by which kMT attachments are controlled by the coordinated function of these protein complexes to drive chromosome motility during early mitosis is still unclear. In this manuscript, we provide evidence to show that Ndc80 and dynein directly antagonize each other’s MT-binding. We also find that severe chromosome alignment defects induced by depletion of dynein, or the dynein adapter spindly, are rescued by codepletion of the RZZ component, Rod, in human cells. Interestingly, the rescue of chromosome alignments defects was independent of Rod function in activation of the spindle assembly checkpoint and was accompanied by a remarkable restoration of stable kMT attachments. Furthermore, rescue of chromosome alignment was critically dependent on the plus-end-directed motility of CENP-E, as cells codepleted of CENP-E along with Rod and dynein were unable to establish stable kMT attachments or align their chromosomes properly. Taken together, our findings support the idea that the dynein motor may control the function of the Ndc80 complex in stabilizing kMT attachments either directly by interfering with Ndc80-MT binding, and/or indirectly by modulating the Rod-mediated inhibition of Ndc80.

scholarly journals Unattached kinetochores rather than intrakinetochore tension arrest mitosis in taxol-treated cells

2016 ◽  
Vol 212 (3) ◽  
pp. 307-319 ◽  
Author(s):  
Valentin Magidson ◽  
Jie He ◽  
Jeffrey G. Ault ◽  
Christopher B. O’Connell ◽  
Nachen Yang ◽  
...  
Keyword(s):  
Light Microscopy ◽  
Spindle Assembly Checkpoint ◽  
Alternative Interpretation ◽  
Mitotic Exit ◽  
Structural Basis ◽  
Mitotic Progression ◽  
Direct Role ◽  
Microtubule Attachment ◽  
Spindle Microtubules ◽  
Shape And Size

Kinetochores attach chromosomes to the spindle microtubules and signal the spindle assembly checkpoint to delay mitotic exit until all chromosomes are attached. Light microscopy approaches aimed to indirectly determine distances between various proteins within the kinetochore (termed Delta) suggest that kinetochores become stretched by spindle forces and compact elastically when the force is suppressed. Low Delta is believed to arrest mitotic progression in taxol-treated cells. However, the structural basis of Delta remains unknown. By integrating same-kinetochore light microscopy and electron microscopy, we demonstrate that the value of Delta is affected by the variability in the shape and size of outer kinetochore domains. The outer kinetochore compacts when spindle forces are maximal during metaphase. When the forces are weakened by taxol treatment, the outer kinetochore expands radially and some kinetochores completely lose microtubule attachment, a condition known to arrest mitotic progression. These observations offer an alternative interpretation of intrakinetochore tension and question whether Delta plays a direct role in the control of mitotic progression.

scholarly journals Activation of cytoplasmic dynein through microtubule crossbridging

2020 ◽  
Author(s):  
Manas Chakraborty ◽  
Algirdas Toleikis ◽  
Nida Siddiqui ◽  
Robert A. Cross ◽  
Anne Straube
Keyword(s):  
Single Molecules ◽  
Cytoplasmic Dynein ◽  
Mitotic Spindles ◽  
Force Output ◽  
Animal Cells ◽  
Physical Separation ◽  
Cargo Transport ◽  
Dynein Motor

SummaryCytoplasmic dynein is the main microtubule-minus-end-directed transporter of cellular cargo in animal cells [1, 2]. Cytoplasmic dynein also functions in the organisation and positioning of mitotic spindles [3, 4] and the formation of ordered microtubule arrays in neurons and muscle [5, 6]. Activation of the motor for cargo transport is thought to require formation of a complex with dynactin and a cargo adapter [7-10]. Here we show that recombinant human dynein can crossbridge neighbouring microtubules and can be activated by this crossbridging to slide and polarity-sort microtubule bundles. While single molecules of human dynein are predominantly static or diffusive on single microtubules, they walk processively for 1.5 μm on average along the microtubule bundles they form. Speed and force output of dynein are doubled on bundles compared to single microtubules, indicating that the crossbridging dynein steps equivalently on two microtubules. Our data are consistent with a model of autoactivation through the physical separation of dynein motor domains when crossbridging two microtubules. This enables cytoplasmic dynein to function effectively as a microtubule organiser and transporter without needing to first form a complex with dynactin and a cargo adapter.

scholarly journals Functional interaction between dynein light chain and intermediate chain is required for mitotic spindle positioning

2011 ◽  
Vol 22 (15) ◽  
pp. 2690-2701 ◽  
Author(s):  
Melissa D. Stuchell-Brereton ◽  
Amanda Siglin ◽  
Jun Li ◽  
Jeffrey K. Moore ◽  
Shubbir Ahmed ◽  
...  
Keyword(s):  
Light Chain ◽  
Direct Evidence ◽  
Retrograde Transport ◽  
Cytoplasmic Dynein ◽  
Dynein Light Chain ◽  
Spindle Positioning ◽  
Dynein Motor ◽  
Intermediate Chains ◽  
Activator Complex

Cytoplasmic dynein is a large multisubunit complex involved in retrograde transport and the positioning of various organelles. Dynein light chain (LC) subunits are conserved across species; however, the molecular contribution of LCs to dynein function remains controversial. One model suggests that LCs act as cargo-binding scaffolds. Alternatively, LCs are proposed to stabilize the intermediate chains (ICs) of the dynein complex. To examine the role of LCs in dynein function, we used Saccharomyces cerevisiae, in which the sole function of dynein is to position the spindle during mitosis. We report that the LC8 homologue, Dyn2, localizes with the dynein complex at microtubule ends and interacts directly with the yeast IC, Pac11. We identify two Dyn2-binding sites in Pac11 that exert differential effects on Dyn2-binding and dynein function. Mutations disrupting Dyn2 elicit a partial loss-of-dynein phenotype and impair the recruitment of the dynein activator complex, dynactin. Together these results indicate that the dynein-based function of Dyn2 is via its interaction with the dynein IC and that this interaction is important for the interaction of dynein and dynactin. In addition, these data provide the first direct evidence that LC occupancy in the dynein motor complex is important for function.

Conversion at large intergenic regions of mitochondrial DNA in Saccharomyces cerevisiae

1990 ◽  
Vol 10 (4) ◽  
pp. 1530-1537
Author(s):  
P J Skelly ◽  
G D Clark-Walker
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitochondrial Dna ◽  
Rrna Gene ◽  
Supporting Evidence ◽  
Unexpected Result ◽  
Wild Type ◽  
Mitochondrial Dna Deletion ◽  
Direct Role ◽  
Atpase Subunit ◽  
Intergenic Regions

Saccharomyces cerevisiae mitochondrial DNA deletion mutants have been used to examine whether base-biased intergenic regions of the genome influence mitochondrial biogenesis. One strain (delta 5.0) lacks a 5-kilobase (kb) segment extending from the proline tRNA gene to the small rRNA gene that includes ori1, while a second strain (delta 3.7) is missing a 3.7-kb region between the genes for ATPase subunit 6 and glutamic acid tRNA that encompasses ori7 plus ori2. Growth of these strains on both fermentable and nonfermentable substrates does not differ from growth of the wild-type strain, indicating that the deletable regions of the genome do not play a direct role in the expression of mitochondrial genes. Examination of whether the 5- or 3.7-kb regions influence mitochondrial DNA transmission was undertaken by crossing strains and examining mitochondrial genotypes in zygotic colonies. In a cross between strain delta 5.0, harboring three active ori elements (ori2, ori3, and ori5), and strain delta 3.7, containing only two active ori elements (ori3 and ori5), there is a preferential recovery of the genome containing two active ori elements (37% of progeny) over that containing three active elements (20%). This unexpected result, suggesting that active ori elements do not influence transmission of respiratory-competent genomes, is interpreted to reflect a preferential conversion of the delta 5.0 genome to the wild type (41% of progeny). Supporting evidence for conversion over biased transmission is shown by preferential recovery of a nonparental genome in the progeny of a heterozygous cross in which both parental molecules can be identified by size polymorphisms.

A Screen for Dynein Synthetic Lethals in Aspergillus nidulans Identifies Spindle Assembly Checkpoint Genes and Other Genes Involved in Mitosis

Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 101-116
Author(s):  
Vladimir P Efimov ◽  
N Ronald Morris
Keyword(s):  
Aspergillus Nidulans ◽  
Spindle Assembly Checkpoint ◽  
Genetic Interaction ◽  
Synthetic Lethality ◽  
Spindle Assembly ◽  
Nuclear Migration ◽  
Cytoplasmic Dynein ◽  
Vesicle Transport ◽  
Synthetic Lethal ◽  
Checkpoint Genes

Abstract Cytoplasmic dynein is a ubiquitously expressed microtubule motor involved in vesicle transport, mitosis, nuclear migration, and spindle orientation. In the filamentous fungus Aspergillus nidulans, inactivation of cytoplasmic dynein, although not lethal, severely impairs nuclear migration. The role of dynein in mitosis and vesicle transport in this organism is unclear. To investigate the complete range of dynein function in A. nidulans, we searched for synthetic lethal mutations that significantly reduced growth in the absence of dynein but had little effect on their own. We isolated 19 sld (synthetic lethality without dynein) mutations in nine different genes. Mutations in two genes exacerbate the nuclear migration defect seen in the absence of dynein. Mutations in six other genes, including sldA and sldB, show a strong synthetic lethal interaction with a mutation in the mitotic kinesin bimC and, thus, are likely to play a role in mitosis. Mutations in sldA and sldB also confer hypersensitivity to the microtubule-destabilizing drug benomyl. sldA and sldB were cloned by complementation of their mutant phenotypes using an A. nidulans autonomously replicating vector. Sequencing revealed homology to the spindle assembly checkpoint genes BUB1 and BUB3 from Saccharomyces cerevisiae. Genetic interaction between dynein and spindle assembly checkpoint genes, as well as other mitotic genes, indicates that A. nidulans dynein plays a role in mitosis. We suggest a model for dynein motor action in A. nidulans that can explain dynein involvement in both mitosis and nuclear distribution.

scholarly journals Stable tug-of-war between kinesin-1 and cytoplasmic dynein upon different ATP and roadblock concentrations

2020 ◽  
Author(s):  
Gina A. Monzon ◽  
Lara Scharrel ◽  
Ashwin DSouza ◽  
Ludger Santen ◽  
Stefan Diez
Keyword(s):  
Cytoplasmic Dynein ◽  
Gliding Motility ◽  
Force Balance ◽  
Stochastic Simulations ◽  
Transport Systems ◽  
Organelle Transport ◽  
Atp Concentration ◽  
Dynein Motor ◽  
Bidirectional Movement

ABSTRACTThe maintenance of intracellular processes like organelle transport and cell division depend on bidirectional movement along microtubules. These processes typically require kinesin and dynein motor proteins which move with opposite directionality. Because both types of motors are often simultaneously bound to the cargo, regulatory mechanisms are required to ensure controlled directional transport. Recently, it has been shown that parameters like mechanical motor activation, ATP concentration and roadblocks on the microtubule surface differentially influence the activity of kinesin and dynein motors in distinct manners. However, how these parameters affect bidirectional transport systems has not been studied. Here, we investigate the regulatory influence of these three parameter using in vitro gliding motility assays and stochastic simulations. We find that the number of active kinesin and dynein motors determines the transport direction and velocity, but that variations in ATP concentration and roadblock density have no significant effect. Thus, factors influencing the force balance between opposite motors appear to be important, whereas the detailed stepping kinetics and bypassing capabilities of the motors have only little effect.

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