Dynein-Driven Mitotic Spindle Positioning Restricted to Anaphase by She1p Inhibition of Dynactin Recruitment

Woodruff, Jeffrey B.; Drubin, David G.; Barnes, Georjana

doi:10.1091/mbc.e09-03-0186

Cited by 39 publications

(85 citation statements)

References 24 publications

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“…We next wanted to investigate the mechanism by which cortical dynein activity was enhanced by Pac1 overexpression. We considered the possibility that dynein and dynactin interaction was enhanced at the cortex, given that a recent study demonstrated that dynein activity is likely regulated via interaction with dynactin (Woodruff et al 2009). Thus, we determined the dynein:dynactin stoichiometry by counting the relative number of molecules of Dyn1-3mCherry and Jnm1-3mCherry at the cell cortex.…”

Section: Resultsmentioning

confidence: 99%

“…This activity is regulated by numerous factors, including dynactin, which has been shown to affect dynein targeting and force production at the cell cortex (Kardon et al 2009; Moore et al 2008; Moore et al 2009a), and She1, which was recently shown to affect the association between dynein and dynactin at MT plus ends (Woodruff et al 2009). Although we previously proposed a model whereby dynein is off-loaded from the plus ends of astral MTs to the cell cortex (Lee et al 2005), the molecular details of this process remain unclear.…”

Section: Introductionmentioning

confidence: 99%

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Quantitative analysis of Pac1/LIS1‐mediated dynein targeting: Implications for regulation of dynein activity in budding yeast

et al. 2011

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LIS1 is a critical regulator of dynein function during mitosis and organelle transport. Here, we investigated how Pac1, the budding yeast LIS1 homologue, regulates dynein targeting and activity during nuclear migration. We show that Pac1 and Dyn1 (dynein heavy chain) are dependent upon each other and upon Bik1 (budding yeast CLIP-170 homologue) for plus end localization, whereas Bik1 is independent of either. Dyn1, Pac1 and Bik1 interact in vivo at the plus ends, where an excess amount of Bik1 recruits approximately equal amounts of Pac1 and Dyn1. Overexpression of Pac1 enhanced plus end targeting of Dyn1 and vice versa, while affinity-purification of Dyn1 revealed that it exists in a complex with Pac1 in the absence of Bik1, leading us to conclude that the Pac1-Dyn1 complex preassembles in the cytoplasm prior to loading onto Bik1-decorated plus ends. Strikingly, we found that Pac1-overexpression augments cortical dynein activity through a mechanism distinct from loss of She1, a negative regulator of dynein-dynactin association. While Pac1-overexpression enhances the frequency of cortical targeting for dynein and dynactin, the stoichiometry of these complexes remains relatively unchanged at the plus ends compared to that in wild-type cells (~3 dynein to 1 dynactin). Loss of She1, however, enhances dynein-dynactin association at the plus ends and the cell cortex, resulting in an apparent 1:1 stoichiometry. Our results reveal differential regulation of cortical dynein activity by She1 and Pac1, and provide a potentially new regulatory step in the off-loading model for dynein function.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Quantitative analysis of Pac1/LIS1‐mediated dynein targeting: Implications for regulation of dynein activity in budding yeast

et al. 2011

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“…The SPC42-GFP and MYO1-GFP alleles were created with plasmids pYM26 and pYM25, respectively, and the SPC42-RFP allele was created with the plasmid pFA6-mCherry-HPH-MX6. The GFP-TUB1 allele comes from strain AC021 (Woodruff et al 2009) and was backcrossed four times in the W303 background. The lacI**-GFP allele was integrated at the URA3 locus (Dubarry et al 2011).…”

Section: Strains and Plasmidsmentioning

confidence: 99%

Cytokinesis breaks dicentric chromosomes preferentially at pericentromeric regions and telomere fusions

et al. 2015

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Dicentric chromosomes are unstable products of erroneous DNA repair events that can lead to further genome rearrangements and extended gene copy number variations. During mitosis, they form anaphase bridges, resulting in chromosome breakage by an unknown mechanism. In budding yeast, dicentrics generated by telomere fusion break at the fusion, a process that restores the parental karyotype and protects cells from rare accidental telomere fusion. Here, we observed that dicentrics lacking telomere fusion preferentially break within a 25-to 30-kb-long region next to the centromeres. In all cases, dicentric breakage requires anaphase exit, ruling out stretching by the elongated mitotic spindle as the cause of breakage. Instead, breakage requires cytokinesis. In the presence of dicentrics, the cytokinetic septa pinch the nucleus, suggesting that dicentrics are severed after actomyosin ring contraction. At this time, centromeres and spindle pole bodies relocate to the bud neck, explaining how cytokinesis can sever dicentrics near centromeres.

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“…This finding suggests that some dynactin subunits, namely Arp1, Mug5 and Jnm1, are regulated through a different mechanism than that of Ssm4. The possibility that dynactin subunits could form subcomplexes with discrete functions was proposed in S. cerevisiae (Moore et al, 2008;Woodruff et al, 2009). …”

Section: Discussionmentioning

confidence: 99%

Dynactin and Num1 cooperate to establish the cortical anchoring of cytoplasmic dynein inS. pombe

Fujita

Yamashita

Yamamoto

2015

Journal of Cell Science

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Chromosome movement during meiosis is crucial for homologous pairing and meiotic recombination. During meiotic prophase in fission yeast, rapid nuclear migration is dependent on cytoplasmic dynein, which is anchored to the cell cortex and pulls microtubules, thereby driving nuclear migration. However, the precise mechanisms underlying dynein localization and activation remain unclear. Here, we identified three subunits of dynactin in fission yeast: Arp1, Mug5 and Jnm1 (also known as Mug1). These subunits transiently colocalized with dynein foci at the cell cortex and were essential for the cortical anchoring of dynein. Cortical factor Num1 (also known as Mcp5), which was also required for dynein anchoring, bound to dynein independently of dynactin. Whereas Num1 suppressed the sliding of dynein foci along the cortex, Arp1, Mug5 and Jnm1 were involved in the regulation of shrinkage and bundling of microtubules. From these data, we propose that dynein anchoring is established by cooperation of transient assembly of dynactin and function of Num1 at the cell cortex.

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Dynein-Driven Mitotic Spindle Positioning Restricted to Anaphase by She1p Inhibition of Dynactin Recruitment

Cited by 39 publications

References 24 publications

Quantitative analysis of Pac1/LIS1‐mediated dynein targeting: Implications for regulation of dynein activity in budding yeast

Quantitative analysis of Pac1/LIS1‐mediated dynein targeting: Implications for regulation of dynein activity in budding yeast

Cytokinesis breaks dicentric chromosomes preferentially at pericentromeric regions and telomere fusions

Dynactin and Num1 cooperate to establish the cortical anchoring of cytoplasmic dynein inS. pombe

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