Plk is a functional homolog of Saccharomyces cerevisiae Cdc5, and elevated Plk activity induces multiple septation structures
Plk is a functional homolog of Saccharomyces cerevisiae Cdc5, and elevated Plk activity induces multiple septation structures
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DOI：
10.1128/mcb.17.6.3408
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发表时间：
1997-06-01
影响因子：
5.3
通讯作者：
Erikson, RL
中科院分区：
文献类型：
--
作者：
Lee, KS;Erikson, RL
PLK是一种哺乳动物丝氨酸/苏氨酸蛋白激酶，其活性在M期开始时达到峰值。它与其他哺乳动物的蛋白激酶SNK、Fnk和Prk密切相关，也与非洲爪哇1、黑腹果蝇Polo、裂殖酵母Plo1和酿酒酵母CDC5密切相关。细胞周期的M期是一个高度协调的过程，确保了细胞分裂过程中遗传物质和细胞物质的均分。为了了解PLK在M期进程中的作用，我们产生了不同的PLK突变体，并在Sf9细胞和发芽酵母中表达。从Sf9细胞制备的PLK免疫沉淀物的体外激酶分析表明，Glu206和Thr210对PLK活性具有同等重要的作用，用带负电荷的残基取代Thr210可以提高PLK的比活性。野生型PLK(PLK WT)的异位表达补充了酿酒酵母中与cdc5-1突变相关的细胞分裂缺陷。互补的程度与体外测定的PLK活性密切相关，因为突变激活的PLK T210D可以增强PLK的活性，但没有观察到K82M、D194N和D194R的失活形式。在CDCS野生型背景下，PLK WT或T210D的表达，但不是非活性形式，诱导了G(1)细胞的急剧积累。与PLK活性升高一致的是，这种现象被C端缺失的形式WT Delta C和T210D Delta C所增强。T210D的表达还诱导了一类具有异常伸长的芽的细胞，形成了多个隔膜结构。然而，在末端缺失的形式T210D Delta C中没有观察到这一点。似乎PLK的C末端对观察到的细胞周期的影响并不是必需的，但对极化细胞的生长和隔膜结构的形成可能是重要的。
Plk is a mammalian serine/threonine protein kinase whose activity peaks at the onset of M phase. It is closely related to other mammalian kinases, Snk, Fnk; and Prk, as well as to Xenopus laevis Plx1, Drosophila melanogaster polo, Schizosaccharomyces pombe Plo1, and Saccharomyces cerevisiae Cdc5. The M phase of the cell cycle is a highly coordinated process which insures the equipartition of genetic and cellular materials during cell division. To enable understanding of the function of Plk during M phase progression, various Plk mutants were generated and expressed in Sf9 cells and budding yeast. In vitro kinase assays with Plk immunoprecipitates prepared from Sf9 cells indicate that Glu206 and Thr210 play equally important roles for Plk activity and that replacement of Thr210 with a negatively charged residue elevates Plk specific activity. Ectopic expression of wild-type Plk (Plk WT) complements the cell division defect associated with the cdc5-1 mutation in S. cerevisiae. The degree of complementation correlates closely with the Plk activity measured in vitro, as it is enhanced by a mutationally activated Plk, T210D, but is not observed,vith the inactive forms K82M, D194N, and D194R. In a CDCS wild-type background, expression of Plk WT or T210D, but not of inactive forms, induced a sharp accumulation of cells in G(1). Consistent with elevated Plk activity, this phenomenon was enhanced by the C-terminally deleted forms WT Delta C and T210D Delta C. Expression of T210D also induced a class of cells with unusually elongated buds which developed multiple septal structures. This was not observed with the C-terminally deleted form T210D Delta C, however. It appears that the C terminus of Plk is not required for the observed cell cycle influence but may be important for polarized cell growth and septal structure formation.