The GTP-binding protein Rho1p is required for cell cycle progression and polarization of the yeast cell.
The GTP-binding protein Rho1p is required for cell cycle progression and polarization of the yeast cell.
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DOI：
10.1083/jcb.146.2.373
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发表时间：
1999-07-26
期刊：
影响因子：
--
通讯作者：
Cabib E
中科院分区：
文献类型：
--
作者：
Drgonová J;Drgon T;Roh DH;Cabib E
先前的研究表明，酿酒酵母中需要 GTP 结合蛋白 Rho1p 来激活蛋白激酶 C (Pkc1p) 以及激活和调节 β(1→3) 葡聚糖合酶。在这里，我们展示了细胞周期进程和细胞极化所需的 Rho1p 的迄今为止未知的功能。处于细胞周期G1期的突变体rho1E45I的细胞在37℃下不出芽。在这些细胞中，肌动蛋白重组和募集到假定的出芽位点在不允许的温度下不会发生。相邻氨基酸的两个突变体 rho1V43T 和 rho1F44Y 显示出相似的行为，尽管在不允许的温度下发生了一些出芽和肌动蛋白极化。当 rho1E45I 置于不同的遗传背景时，情况也是如此。 Cdc42p 和 Spa2p 这两种蛋白质通常也会在独立于肌动蛋白组织的过程中移动到芽位点，但未能在 rho1E45I 中正确定位。尽管 DNA 复制进行缓慢，但 37°C 下突变体并未发生核分裂。 rho1突变体在交配突起的形成以及交配信息素存在下肌动蛋白在突起处的聚集方面也存在缺陷。 rho1 E45I 中 β(1→3) 葡聚糖合酶的体外活性虽然在 37°C 时减弱，但似乎足以维持正常的体内功能，并且 PKC1 组成型活性等位基因的表达不会抑制出芽缺陷。相反，当使用温度敏感突变消除 Pkc1p 功能并使用棘白菌素样抑制剂消除 β(1→3) 葡聚糖合成时，携带野生型 RHO1 等位基因的菌株能够产生初生芽。总而言之，这些结果揭示了 Rho1p 的一种新功能，必须执行该功能才能使酵母细胞极化。
Previous work showed that the GTP-binding protein Rho1p is required in the yeast, Saccharomyces cerevisiae, for activation of protein kinase C (Pkc1p) and for activity and regulation of β(1→3)glucan synthase. Here we demonstrate a hitherto unknown function of Rho1p required for cell cycle progression and cell polarization. Cells of mutant rho1E45I in the G1 stage of the cell cycle did not bud at 37°C. In those cells actin reorganization and recruitment to the presumptive budding site did not take place at the nonpermissive temperature. Two mutants in adjacent amino acids, rho1V43T and rho1F44Y, showed a similar behavior, although some budding and actin polarization occurred at the nonpermissive temperature. This was also the case for rho1E45I when placed in a different genetic background. Cdc42p and Spa2p, two proteins that normally also move to the bud site in a process independent from actin organization, failed to localize properly in rho1E45I. Nuclear division did not occur in the mutant at 37°C, although replication of DNA proceeded slowly. The rho1 mutants were also defective in the formation of mating projections and in congregation of actin at the projections in the presence of mating pheromone. The in vitro activity of β(1→3)glucan synthase in rho1 E45I, although diminished at 37°C, appeared sufficient for normal in vivo function and the budding defect was not suppressed by expression of a constitutively active allele of PKC1. Reciprocally, when Pkc1p function was eliminated by the use of a temperature-sensitive mutation and β(1→3)glucan synthesis abolished by an echinocandin-like inhibitor, a strain carrying a wild-type RHO1 allele was able to produce incipient buds. Taken together, these results reveal a novel function of Rho1p that must be executed in order for the yeast cell to polarize.
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影响因子：
3.2
作者：
DOUGLAS, CM;MARRINAN, JA;KURTZ, MB
通讯作者：
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影响因子：
2.5
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3.2
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影响因子：
56.9
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通讯作者：
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作者：
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