XRHAMM Functions in Ran-Dependent Microtubule Nucleation and Pole Formation during Anastral Spindle Assembly

@article{Groen2004XRHAMMFI,
  title={XRHAMM Functions in Ran-Dependent Microtubule Nucleation and Pole Formation during Anastral Spindle Assembly},
  author={Aaron C. Groen and Lisa A. Cameron and Margaret L. Coughlin and David T. Miyamoto and Timothy J. Mitchison and Ryoma Ohi},
  journal={Current Biology},
  year={2004},
  volume={14},
  pages={1801-1811}
}
BACKGROUND The regulated assembly of microtubules is essential for bipolar spindle formation. Depending on cell type, microtubules nucleate through two different pathways: centrosome-driven or chromatin-driven. The chromatin-driven pathway dominates in cells lacking centrosomes. RESULTS Human RHAMM (receptor for hyaluronic-acid-mediated motility) was originally implicated in hyaluronic-acid-induced motility but has since been shown to associate with centrosomes and play a role in astral… Expand
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TLDR
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TLDR
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TLDR
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TLDR
The resulting TPX2-RHAMM-γTuRC supracomplex fulfills the two essential requirements for the activation of MT nucleation by RanGTP: NEDD1 phosphorylation on S405 by the TP X2-activated Aurora A and the recruitment of the complex onto a TPX 2-dependent scaffold. Expand
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References

SHOWING 1-10 OF 70 REFERENCES
Generation of GTP-bound Ran by RCC1 is required for chromatin-induced mitotic spindle formation
TLDR
It is shown that the activity of chromosome-associated RCC1 protein is required for spindle formation and a high local concentration of Ran-GTP around chromatin is proposed which in turn induces the local nucleation of microtubules. Expand
A model for the proposed roles of different microtubule-based motor proteins in establishing spindle bipolarity
TLDR
Multiple microtubule-based motor activities are required for the bipolar organization of microtubules around chromatin beads, and a model for the roles of the individual motor proteins in this process is proposed. Expand
Importin β Is a Mitotic Target of the Small GTPase Ran in Spindle Assembly
TLDR
It is shown that the mitotic role of Ran is largely mediated by the nuclear transport factor importin β, and it is proposed that RanGTP functions in mitosis as in interphase by locally releasing cargoes from transport factors. Expand
Mitotic Spindle Poles are Organized by Structural and Motor Proteins in Addition to Centrosomes
TLDR
It is shown that an antibody recognizing the light intermediate chain of cytoplasmic dynein disrupts both the focused organization of microtubule minus ends and the localization of the nuclear mitotic apparatus protein at spindle poles when injected into cultured cells during metaphase, despite the presence of centrosomes. Expand
Importin α‐regulated nucleation of microtubules by TPX2
TLDR
The data suggest that the critical early function in spindle formation regulated by importin α is TPX2‐mediated microtubule nucleation. Expand
A Complex of NuMA and Cytoplasmic Dynein Is Essential for Mitotic Spindle Assembly
TLDR
It is suggested that NuMA forms bifunctional complexes with cytoplasmic dynein and dynactin that can tether microtubules at the spindle poles and that are essential for mitotic spindle pole assembly and stabilization. Expand
Formation of Spindle Poles by Dynein/Dynactin-Dependent Transport of Numa
TLDR
It is shown that this process depends on directed NuMA transport toward microtubule minus ends powered by cytoplasmic dynein and its activator dynactin, which strongly inhibits NuMA translocation and accumulation and disrupts spindle pole assembly. Expand
Spindle Assembly in Xenopus Egg Extracts: Respective Roles of Centrosomes and Microtubule Self-Organization
TLDR
It is found that poles are morphologically similar regardless of their origin and can regulate the organization of microtubules into a bipolar array. Expand
An inner centromere protein that stimulates the microtubule depolymerizing activity of a KinI kinesin.
TLDR
By immunoelectron microscopy, it is found that ICIS is present on the surface of inner centromeres, placing it in an ideal location to depolymerize microtubules associated laterally with inner centromres and provide a mechanism that prevents kinetochore-microtubule attachment errors. Expand
RHAMM is a centrosomal protein that interacts with dynein and maintains spindle pole stability.
TLDR
It is demonstrated that a subset of cellular RHAMM localizes to the centrosome and functions in the maintenance of spindle integrity and provides a potential mechanism for this function in that RHAMm may cross-link centrosomal microtubules, through a direct interaction withmicrotubules and an association with dynein. Expand
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5
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