Poleward Transport of TPX2 in the Mammalian Mitotic Spindle Requires Dynein, Eg5, and Microtubule Flux
Abstract
TPX2 is a Ran-regulated spindle assembly factor that is required for kinetochore fiber
formation and activation of the mitotic kinase Aurora A. TPX2 is enriched near spindle
poles and is required near kinetochores, suggesting that it undergoes dynamic relocalization
throughout mitosis. Using photoactivation, we measured the movement of PA-GFP-TPX2
in the mitotic spindle. TPX2 moves poleward in the half-spindle and is static in the
interzone and near spindle poles. Poleward transport of TPX2 is sensitive to inhibition
of dynein or Eg5 and to suppression of microtubule flux with nocodazole or antibodies
to Kif2a. Poleward transport requires the C terminus of TPX2, a domain that interacts
with Eg5. Overexpression of TPX2 lacking this domain induced excessive microtubule
formation near kinetochores, defects in spindle assembly and blocked mitotic progression.
Our data support a model in which poleward transport of TPX2 down-regulates its microtubule
nucleating activity near kinetochores and links microtubules generated at kinetochores
to dynein for incorporation into the spindle.
Type
Journal articleSubject
kinetochore fibers contributesaurora-a activation
dynamic
instability
self-organization
cells
poles
centrosomes
dynactin
extracts
protein
cell biology
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https://hdl.handle.net/10161/3306Published Version (Please cite this version)
10.1091/mbc.E09-07-0601Citation
Ma,Nan;Tulu,U. S.;Ferenz,Nick P.;Fagerstrom,Carey;Wilde,Andrew;Wadsworth,Patricia.
2010. Poleward Transport of TPX2 in the Mammalian Mitotic Spindle Requires Dynein,
Eg5, and Microtubule Flux. Molecular biology of the cell 21(6): 979-988.
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