Poleward tubulin flux in spindles: regulation and function in mitotic cells

The poleward flux of tubulin subunits through spindle microtubules is a striking and conserved phenomenon whose function and molecular components remain poorly understood. To screen for novel components of the flux machinery, we utilized RNA interference to deplete regulators of microtubule dynamics...

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Bibliographic Details
Published in:Molecular biology of the cell 2007-08, Vol.18 (8), p.3094-3104
Main Authors: Buster, Daniel W, Zhang, Dong, Sharp, David J
Format: Article
Language:English
Subjects:
Anaphase
Animals
Cell Polarity
Chromosome Segregation
Chromosomes - metabolism
Drosophila melanogaster - cytology
Drosophila melanogaster - metabolism
Drosophila Proteins - metabolism
Kinesin - metabolism
Kinetochores - metabolism
Microtubules - metabolism
Mitosis
Models, Biological
Spindle Apparatus - metabolism
Tubulin - metabolism
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Summary:The poleward flux of tubulin subunits through spindle microtubules is a striking and conserved phenomenon whose function and molecular components remain poorly understood. To screen for novel components of the flux machinery, we utilized RNA interference to deplete regulators of microtubule dynamics, individually and in various combinations, from S2 cells and examined the resulting impact on flux rate. This led to the identification of two previously unknown flux inhibitors, KLP59C and KLP67A, and a flux promoter, Mini-spindles. Furthermore, we find that flux rate is regulated by functional antagonism among microtubule stabilizers and destabilizers specifically at plus ends. Finally, by examining mitosis on spindles in which flux has been up- or down-regulated or restored after the codepletion of antagonistic flux regulators, we show that flux is an integral contributor to anaphase A but is not responsible for chromosome congression, interkinetochore tension, or the establishment of normal spindle length during prometaphase/metaphase.
ISSN:1059-1524
1939-4586
DOI:10.1091/mbc.E06-11-0994