Distinct subcellular localization patterns contribute to functional specificity of the Cln2 and Cln3 cyclins of Saccharomyces cerevisiae
Distinct subcellular localization patterns contribute to functional specificity of the Cln2 and Cln3 cyclins of Saccharomyces cerevisiae
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DOI：
10.1128/mcb.20.2.542-555.2000
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发表时间：
2000-01-01
影响因子：
5.3
通讯作者：
Cross, FR
中科院分区：
文献类型：
--
作者：
Miller, ME;Cross, FR
芽殖酵母的G（1）细胞周期蛋白通过不同的机制驱动细胞周期启动，但其特异性的分子基础尚不清楚。在这里，我们测试的假设，G（1）细胞周期蛋白的功能特异性是由于不同的亚细胞定位。如通过间接免疫荧光和生化分级分离所示，Cln3p定位似乎主要是细胞核，其中Cln3p最明显地积累到大出芽细胞的细胞核。相比之下，Cln2p定位于细胞质。我们能够通过添加核定位和核输出信号来改变截短的Cln3p的定位模式，并且我们发现核定位驱动Cln3p样功能谱，而细胞质定位导致部分转变为Cln2p样功能谱。因此，迫使Cln3p进入Cln2p样细胞质定位模式部分改变了Cln3p对Cln2p的功能特异性。这些结果表明，有CLN依赖的细胞质和细胞核的事件重要的细胞周期的启动。这是细胞周期蛋白依赖性激酶的细胞质功能的第一个迹象。这里提供的数据支持这样的观点：细胞周期蛋白功能在亚细胞定位水平上受到调节，并且亚细胞定位有助于Cln 2 p和Cln 3 p的功能特异性。
The G(1) cyclins of budding yeast drive cell cycle initiation by different mechanisms, but the molecular basis of their specificity is unknown. Here we test the hypothesis that the functional specificity of G(1) cyclins is due to differential subcellular localization. As shown by indirect immunofluorescence and biochemical fractionation, Cln3p localization appears to be primarily nuclear, with the most obvious accumulation of Cln3p to the nuclei of large budded cells. In contrast, Cln2p localizes to the cytoplasm, We were able to shift localization patterns of truncated Cln3p by the addition of nuclear localization and nuclear export signals, and we found that nuclear localization drives a Cln3p-like functional profile, while cytoplasmic localization leads to a partial shift to a Cln2p-like functional profile. Therefore, forcing Cln3p into a Cln2p-like cytoplasmic localization pattern partially alters the functional specificity of Cln3p toward that of Cln2p. These results suggest that there are CLN-dependent cytoplasmic and nuclear events important for cell cycle initiation. This is the first indication of a cytoplasmic function for a cyclin-dependent kinase. The data presented here support the idea that cyclin function is regulated at the level of subcellular localization and that subcellular localization contributes to the functional specificity of Cln2p and Cln3p.