Microtubule dependency of p34cdc2 inactivation and mitotic exit in mammalian cells.
Microtubule dependency of p34cdc2 inactivation and mitotic exit in mammalian cells.
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DOI：
10.1083/jcb.127.3.789
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发表时间：
1994-11
期刊：
影响因子：
--
通讯作者：
Margolis RL
中科院分区：
文献类型：
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作者：
Andreassen PR;Margolis RL
蛋白激酶抑制剂2-氨基嘌呤在BHK细胞中诱导检查点超驰和有丝分裂退出，这些细胞已被微管功能抑制剂(Andreassen，P.R.和R.L.MarGolis)阻止在有丝分裂中。1991年。J.细胞科学。100：299-310)。有丝分裂的退出通过MPM-2抗原的丢失、细胞核的重塑和依赖于p34cdc2的H1激酶活性的消退来监测。2-AP诱导的p34cdc2失活和有丝分裂退出依赖于微管的组装状态。在微管组装抑制剂诺可达唑诱导的有丝分裂停滞过程中，2-AP诱导的有丝分裂退出率随着诺可达唑浓度的增加而成比例下降。当诺可达唑浓度为0.12微克/毫升或更高时，2-AP处理75分钟后不能引起明显的退出。相反，2-AP使有丝分裂停止(T1/2=20分钟)迅速退出紫杉醇，紫杉醇是一种导致微管不适当过度组装的药物。在对照有丝分裂细胞中，p34cdc2定位于动粒、中心体和纺锤体微管。我们发现，在p34cdc2仍然与中心体微管相关的条件下，有效地退出有丝分裂，这表明它必须存在于这些微管上才能被灭活。有丝分裂滑移，即细胞在长时间的有丝分裂阻断期间自然重新进入G1期，也是微管依赖的。在较高浓度下，诺康唑可防止细胞滑脱，并使有丝分裂停止接近100%。我们得出的结论是，有丝分裂纺锤体上存在着退出有丝分裂机制的基本组件，因此正常的有丝分裂退出可能受到微管组装状态的调节。
The protein kinase inhibitor 2-aminopurine induces checkpoint override and mitotic exit in BHK cells which have been arrested in mitosis by inhibitors of microtubule function (Andreassen, P. R., and R. L. Margolis. 1991. J. Cell Sci. 100:299-310). Mitotic exit is monitored by loss of MPM-2 antigen, by the reformation of nuclei, and by the extinction of p34cdc2-dependent H1 kinase activity. 2-AP-induced inactivation of p34cdc2 and mitotic exit depend on the assembly state of microtubules. During mitotic arrest generated by the microtubule assembly inhibitor nocodazole, the rate of mitotic exit induced by 2-AP decreases proportionally with increasing nocodazole concentrations. At nocodazole concentrations of 0.12 microgram/ml or greater, 2-AP induces no apparent exit through 75 min of treatment. In contrast, 2-AP brings about a rapid exit (t1/2 = 20 min) from mitotic arrest by taxol, a drug which causes inappropriate overassembly of microtubules. In control mitotic cells, p34cdc2 localizes to kinetochores, centrosomes, and spindle microtubules. We find that efficient exit from mitosis occurs under conditions where p34cdc2 remains associated with centrosomal microtubules, suggesting it must be present on these microtubules in order to be inactivated. Mitotic slippage, the natural reentry of cells into G1 during prolonged mitotic block, is also microtubule dependent. At high nocodazole concentrations slippage is prevented and mitotic arrest approaches 100%. We conclude that essential components of the machinery for exit from mitosis are present on the mitotic spindle, and that normal mitotic exit thereby may be regulated by the microtubule assembly state.