Requirement of aurora-A kinase in astral microtubule polymerization and spindle microtubule flux.
Mitotic Aurora-A kinase was found to be required for formation of bipolar spindle, ensuring accurate chromosome segregation in mitosis. Recently, Aurora-A was shown to promote Ran-GTP-induced spindle formation and astral microtubule development. Here, by selective immunodepletion, we showed that Aurora-A was required for centrosome- but not Ran-GTP-induced astral microtubule formation in Xenopus egg extracts. Aurora-A enhanced microtubule polymerization in both centrosome- and Ran-GTP-induced aster assemblies: shortening the timing of aster assembly and increasing the aster size. Indeed, adding of Aurora-A protein alone induced microtubule clustering, which was abrogated by Aurora kinase inhibitory small molecule ZM447439. In addition, we showed that Aurora-A was indispensable for Ran-GTP-induced bipolar spindle formation. Inhibition of Aurora-A activity by adding of kinase inactive dominant mutant led to spindle collapse and formation of monopolar spindle whereas minus-end motor protein dynein/dynactin inhibitor p50/dynamitin rescued the bipolar structure. Lastly, we revealed that Aurora-A was necessary for microtubule poleward flux and this requirement depended on kinase activity. Thus, we showed that Aurora-A promoted microtubule polymerization and maintained microtubule flux in ensuring proper bipolar spindle assembly.
Wang
Li-Hui
LH
Department of Experimental Research, State Key Laboratory of Oncology in Southern China, Cancer Center, Sun Yat-sen University, Guangzhou, China.
Yan
Min
M
Xu
Da-Zhi
DZ
Cao
Jun-Xia
JX
Zhu
Xiao-Feng
XF
Zeng
Yi-Xin
YX
Liu
Quentin
Q
D000818:Animals; D064127:Aurora Kinases; D001549:Benzamides; D001692:Biological Transport / Q000502:physiology; D020090:Chromosome Segregation / Q000502:physiology*; D015151:Immunoblotting; D008870:Microtubules / Q000378:metabolism*; D011108:Polymers; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011799:Quinazolines; D008941:Spindle Apparatus / Q000378:metabolism*; D014981:Xenopus
C474722:4-(4-(N-benzoylamino)anilino)-6-methoxy-7-(3-(1-morpholino)propoxy)quinazoline; D001549:Benzamides; D011108:Polymers; D011799:Quinazolines; D064127:Aurora Kinases; D017346:Protein Serine-Threonine Kinases