scholarly journals Saccharomyces cerevisiae genes required in the absence of the CIN8-encoded spindle motor act in functionally diverse mitotic pathways.

1997 ◽  
Vol 8 (6) ◽  
pp. 1035-1050 ◽  
Author(s):  
J R Geiser ◽  
E J Schott ◽  
T J Kingsbury ◽  
N B Cole ◽  
L J Totis ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cytoplasmic Dynein ◽  
Spindle Pole ◽  
Spindle Motor ◽  
Normal Brain ◽  
Cellular Interactions ◽  
Spindle Positioning ◽  
Pathway Gene ◽  
Functionally Diverse ◽  
Dynactin Complex

Kinesin-related Cin8p is the most important spindle-pole-separating motor in Saccharomyces cerevisiae but is not essential for cell viability. We identified 20 genes whose products are specifically required by cell deficient for Cin8p. All are associated with mitotic roles and represent at least four different functional pathways. These include genes whose products act in two spindle motor pathways that overlap in function with Cin8p, the kinesin-related Kip1p pathway and the cytoplasmic dynein pathway. In addition, genes required for mitotic spindle checkpoint function and for normal microtubule stability were recovered. Mutant alleles of eight genes caused phenotypes similar to dyn1 (encodes the dynein heavy chain), including a spindle-positioning defect. We provide evidence that the products of these genes function in concept with dynein. Among the dynein pathway gene products, we found homologues of the cytoplasmic dynein intermediate chain, the p150Glued subunit of the dynactin complex, and human LIS-1, required for normal brain development. These findings illustrate the complex cellular interactions exhibited by Cin8p, a member of a conserved spindle motor family.

scholarly journals Formation of Spindle Poles by Dynein/Dynactin-Dependent Transport of Numa

2000 ◽  
Vol 149 (4) ◽  
pp. 851-862 ◽  
Author(s):  
Andreas Merdes ◽  
Rebecca Heald ◽  
Kumiko Samejima ◽  
William C. Earnshaw ◽  
Don W. Cleveland
Keyword(s):  
Fluorescent Protein ◽  
Gel Filtration ◽  
Cytoplasmic Dynein ◽  
Spindle Pole ◽  
Nuclear Envelope Breakdown ◽  
Spindle Poles ◽  
Mitotic Spindle Assembly ◽  
Green Fluorescent ◽  
Dependent Transport ◽  
Dynactin Complex

NuMA is a large nuclear protein whose relocation to the spindle poles is required for bipolar mitotic spindle assembly. We show here that this process depends on directed NuMA transport toward microtubule minus ends powered by cytoplasmic dynein and its activator dynactin. Upon nuclear envelope breakdown, large cytoplasmic aggregates of green fluorescent protein (GFP)-tagged NuMA stream poleward along spindle fibers in association with the actin-related protein 1 (Arp1) protein of the dynactin complex and cytoplasmic dynein. Immunoprecipitations and gel filtration demonstrate the assembly of a reversible, mitosis-spe-cific complex of NuMA with dynein and dynactin. NuMA transport is required for spindle pole assembly and maintenance, since disruption of the dynactin complex (by increasing the amount of the dynamitin subunit) or dynein function (with an antibody) strongly inhibits NuMA translocation and accumulation and disrupts spindle pole assembly.

scholarly journals LIS1 at the microtubule plus end and its role in dynein-mediated nuclear migration

2003 ◽  
Vol 160 (3) ◽  
pp. 289-290 ◽  
Author(s):  
Xin Xiang
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nuclear Migration ◽  
Cytoplasmic Dynein ◽  
Causal Gene ◽  
New Findings ◽  
Dynactin Complex

The cytoplasmic dynein complex and its accessory dynactin complex are involved in many cellular activities including nuclear migration in fungi (for review see Karki and Holzbaur, 1999). LIS1, the product of a causal gene for human lissencephaly (smooth brain), has also been implicated in dynein function based on studies in fungi and more recent studies in higher eukaryotic systems (for review see Gupta et al., 2002). Exactly how LIS1 may regulate the behavior of cytoplasmic dynein in various organisms is a fascinating question. In this issue, Lee et al. (2003) describe important new findings in Saccharomyces cerevisiae regarding the role of LIS1 (Pac1) in dynein-mediated nuclear migration.

scholarly journals The Nuclear Mitotic Apparatus (NuMA) Protein: A Key Player for Nuclear Formation, Spindle Assembly, and Spindle Positioning

2021 ◽  
Vol 9 ◽  
Author(s):  
Tomomi Kiyomitsu ◽  
Susan Boerner
Keyword(s):  
Protein A ◽  
Spindle Assembly ◽  
Mitotic Cell ◽  
Cytoplasmic Dynein ◽  
Spindle Pole ◽  
Meiotic Spindle ◽  
Cell Cortex ◽  
Mitotic Apparatus ◽  
Spindle Positioning ◽  
Nuclear Mitotic Apparatus

The nuclear mitotic apparatus (NuMA) protein is well conserved in vertebrates, and dynamically changes its subcellular localization from the interphase nucleus to the mitotic/meiotic spindle poles and the mitotic cell cortex. At these locations, NuMA acts as a key structural hub in nuclear formation, spindle assembly, and mitotic spindle positioning, respectively. To achieve its variable functions, NuMA interacts with multiple factors, including DNA, microtubules, the plasma membrane, importins, and cytoplasmic dynein. The binding of NuMA to dynein via its N-terminal domain drives spindle pole focusing and spindle positioning, while multiple interactions through its C-terminal region define its subcellular localizations and functions. In addition, NuMA can self-assemble into high-ordered structures which likely contribute to spindle positioning and nuclear formation. In this review, we summarize recent advances in NuMA’s domains, functions and regulations, with a focus on human NuMA, to understand how and why vertebrate NuMA participates in these functions in comparison with invertebrate NuMA-related proteins.

scholarly journals Cytoplasmic dynein and actin-related protein Arp1 are required for normal nuclear distribution in filamentous fungi.

1994 ◽  
Vol 127 (1) ◽  
pp. 139-149 ◽  
Author(s):  
M Plamann ◽  
P F Minke ◽  
J H Tinsley ◽  
K S Bruno
Keyword(s):  
Cytoplasmic Dynein ◽  
Spindle Pole ◽  
Related Protein ◽  
Nuclear Distribution ◽  
Spindle Pole Bodies ◽  
Fungal Hyphae ◽  
Genes Encoding ◽  
Dynactin Complex

Cytoplasmic dynein is a multisubunit, microtubule-dependent mechanochemical enzyme that has been proposed to function in a variety of intracellular movements, including minus-end-directed transport of organelles. Dynein-mediated vesicle transport is stimulated in vitro by addition of the Glued/dynactin complex raising the possibility that these two complexes interact in vivo. We report here that a class of phenotypically identical mutants of the filamentous fungus Neurospora crassa are defective in genes encoding subunits of either cytoplasmic dynein or the Glued/dynactin complex. These mutants, defined as ropy, have curled hyphae with abnormal nuclear distribution. ro-1 encodes the heavy chain of cytoplasmic dynein, while ro-4 encodes an actin-related protein that is a probable homologue of the actin-related protein Arpl (formerly referred to as actin-RPV or centractin), the major component of the glued/dynactin complex. The phenotypes of ro-1 and ro-4 mutants suggest that cytoplasmic dynein, as well as the Glued/dynactin complex, are required to maintain uniform nuclear distribution in fungal hyphae. We propose that cytoplasmic dynein maintains nuclear distribution through sliding of antiparallel microtubules emanating from neighboring spindle pole bodies.

scholarly journals Novel Roles for Saccharomyces cerevisiae Mitotic Spindle Motors

1999 ◽  
Vol 147 (2) ◽  
pp. 335-350 ◽  
Author(s):  
Frank R. Cottingham ◽  
Larisa Gheber ◽  
Dana L. Miller ◽  
M. Andrew Hoyt
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mitotic Spindle ◽  
Structural Integrity ◽  
Cytoplasmic Dynein ◽  
Spindle Positioning ◽  
Bipolar Spindle ◽  
Accessory Factor ◽  
Spindle Function ◽  
Related Proteins ◽  
Spindle Structure

The single cytoplasmic dynein and five of the six kinesin-related proteins encoded by Saccharomyces cerevisiae participate in mitotic spindle function. Some of the motors operate within the nucleus to assemble and elongate the bipolar spindle. Others operate on the cytoplasmic microtubules to effect spindle and nuclear positioning within the cell. This study reveals that kinesin-related Kar3p and Kip3p are unique in that they perform roles both inside and outside the nucleus. Kar3p, like Kip3p, was found to be required for spindle positioning in the absence of dynein. The spindle positioning role of Kar3p is performed in concert with the Cik1p accessory factor, but not the homologous Vik1p. Kar3p and Kip3p were also found to overlap for a function essential for the structural integrity of the bipolar spindle. The cytoplasmic and nuclear roles of both these motors could be partially substituted for by the microtubule-destabilizing agent benomyl, suggesting that these motors perform an essential microtubule-destabilizing function. In addition, we found that yeast cell viability could be supported by as few as two microtubule-based motors: the BimC-type kinesin Cin8p, required for spindle structure, paired with either Kar3p or Kip3p, required for both spindle structure and positioning.

scholarly journals Dynein collective behavior in mitotic nuclear positioning of Saccharomyces cerevisiae

2020 ◽  
Author(s):  
Kunalika Jain ◽  
Neha Khetan ◽  
Saravanan Palani ◽  
Chaitanya A. Athale
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cytoplasmic Dynein ◽  
Spindle Pole ◽  
Force Balance ◽  
Nuclear Positioning ◽  
Spindle Pole Bodies ◽  
Bud Neck ◽  
Pulling Forces ◽  
Short Time

1AbstractPositioning the nucleus at the bud-neck prior during Saccharomyces cerevisiae mitosis during anaphase involves pulling forces of cytoplasmic dynein localized in the daughter cell. While genetic analysis has revealed a complex network positioning the nucleus, quantification of the forces acting on the nucleus and dyneins numbers driving the process has remained difficult. In order to better understand the role of motor-microtubule mechanics during nuclear positioning and the role of dynein, we have used a computational model of nuclear mobility in S. cerevisiae and reconciled it to the mobility of labelled spindle pole bodies (SPBs) measured by quantifying fluorescence microscopy time-series. We model the apparent random-walk mobility of SPBs by combining diffusion of the nucleus and active pushing of MTs at the cell membrane. By minimizing the deviation between tracks of fluorescently tagged SPBs and simulations, we estimate the effective cytoplasmic viscosity to be 0.5 Pa s. The directed transport of nuclei during the budding process is similarly quantified by tracking the daughter SPB (SPB-D) in experiment. Using force-balance, we find 2 to 8 motors are required to pull the nucleus to the bud-neck. Simulations of the cytoplasmic MT (cMT) ‘search and capture’ by dynein suggest single motor binding is followed by a rapid saturation of number of bound motors. The short time and length of MT interactions with the cortex and minimal collective dynein force required, predict a functional role for dynein clustering in nuclear positioning.

Ady3p Links Spindle Pole Body Function to Spore Wall Synthesis in Saccharomyces cerevisiae

Genetics ◽  
2002 ◽  
Vol 160 (4) ◽  
pp. 1439-1450
Author(s):  
Mark E Nickas ◽  
Aaron M Neiman
Keyword(s):  
Saccharomyces Cerevisiae ◽  
De Novo ◽  
Spindle Pole Body ◽  
Leading Edge ◽  
Spindle Pole ◽  
Spore Wall ◽  
Pole Body ◽  
Prospore Membrane ◽  
Sporulation Efficiency ◽  
Spore Walls

Abstract Spore formation in Saccharomyces cerevisiae requires the de novo synthesis of prospore membranes and spore walls. Ady3p has been identified as an interaction partner for Mpc70p/Spo21p, a meiosis-specific component of the outer plaque of the spindle pole body (SPB) that is required for prospore membrane formation, and for Don1p, which forms a ring-like structure at the leading edge of the prospore membrane during meiosis II. ADY3 expression has been shown to be induced in midsporulation. We report here that Ady3p interacts with additional components of the outer and central plaques of the SPB in the two-hybrid assay. Cells that lack ADY3 display a decrease in sporulation efficiency, and most ady3Δ/ady3Δ asci that do form contain fewer than four spores. The sporulation defect in ady3Δ/ady3Δ cells is due to a failure to synthesize spore wall polymers. Ady3p forms ring-like structures around meiosis II spindles that colocalize with those formed by Don1p, and Don1p rings are absent during meiosis II in ady3Δ/ady3Δ cells. In mpc70Δ/mpc70Δ cells, Ady3p remains associated with SPBs during meiosis II. Our results suggest that Ady3p mediates assembly of the Don1p-containing structure at the leading edge of the prospore membrane via interaction with components of the SPB and that this structure is involved in spore wall formation.

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.

scholarly journals Dynein Light Chain 1 Regulates Dynamin-mediated F-Actin Assembly during Sperm Individualization in Drosophila

2005 ◽  
Vol 16 (7) ◽  
pp. 3107-3116 ◽  
Author(s):  
Anindya Ghosh-Roy ◽  
Bela S. Desai ◽  
Krishanu Ray
Keyword(s):  
Light Chain ◽  
Cytoplasmic Dynein ◽  
Actin Dynamics ◽  
Dynein Light Chain ◽  
Actin Assembly ◽  
Cellular Functions ◽  
Directed Movement ◽  
Cellular Processes ◽  
Dynactin Complex

Toward the end of spermiogenesis, spermatid nuclei are compacted and the clonally related spermatids individualize to become mature and active sperm. Studies in Drosophila showed that caudal end-directed movement of a microfilament-rich structure, called investment cone, expels the cytoplasmic contents of individual spermatids. F-actin dynamics plays an important role in this process. Here we report that the dynein light chain 1 (DLC1) of Drosophila is involved in two separate cellular processes during sperm individualization. It is enriched around spermatid nuclei during postelongation stages and plays an important role in the dynein-dynactin–dependent rostral retention of the nuclei during this period. In addition, DDLC1 colocalizes with dynamin along investment cones and regulates F-actin assembly at this organelle by retaining dynamin along the cones. Interestingly, we found that this process does not require the other subunits of cytoplasmic dynein-dynactin complex. Altogether, these observations suggest that DLC1 could independently regulate multiple cellular functions and established a novel role of this protein in F-actin assembly in Drosophila.

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