Roles of the three Ras proteins in the regulation of dimorphic transition in the yeast Yarrowia lipolytica
Roles of the three Ras proteins in the regulation of dimorphic transition in the yeast Yarrowia lipolytica
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三种 Ras 蛋白在解脂耶氏酵母二态性转变调节中的作用
DOI：
10.1111/1567-1364.12129
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发表时间：
2014-05-01
影响因子：
3.2
通讯作者：
Gao, Xiang-Dong
中科院分区：
文献类型：
--
作者：
Li, Min;Li, Yun-Qing;Gao, Xiang-Dong
酿酒酵母芽生酵母中的RAS蛋白对酵母的生长和二态转变是必不可少的。溶脂亚罗维菌与酿酒酵母有较远的亲缘关系。它的基因组编码三种RAS蛋白。在这里，我们证明了溶脂耶尔森菌中的三种RAS蛋白对二态转变是关键的，但对生长是必不可少的。在这三种RAS蛋白中，YlRas2在调节二态转换中起主要作用，而YlRas1在这一过程中起次要作用。附加的Ras蛋白YlRas3在C末端类似于哺乳动物的K-Ras4B，似乎在二态转换中没有明显的作用。因此，这三种RAS蛋白在调节二态转换中的作用并不相同。我们还发现YlRAS2在酵母到菌丝的转变过程中在转录水平上显著增加，这与YlRas2在调节二态转变中的主要作用是一致的。YlRas2在二态转变中的S功能依赖于YlRas2的活性GTP结合形式及其在质膜上的定位。YlRas2也可以部分作用于内膜。此外，我们还发现转录因子Mhy1是YlRas2下游控制二态转换的潜在信号转导因子。这一发现表明，溶脂耶尔森菌中可能存在由调节二态转换的Ras蛋白控制的新的信号通路。
Ras proteins in the budding yeast Saccharomyces cerevisiae are essential for growth and dimorphic transition. The dimorphic yeast Yarrowia lipolytica is distantly related to S.cerevisiae. Its genome encodes three Ras proteins. Here, we show that the three Ras proteins in Y.lipolytica are critical for dimorphic transition but are dispensable for growth. Among the three Ras proteins, YlRas2 plays a major role in the regulation of dimorphic transition, whereas YlRas1 plays a minor role in this process. The additional Ras protein, YlRas3, which resembles mammalian K-Ras4B at the C-terminus, does not seem to have a significant role in dimorphic transition. Thus, the three Ras proteins do not act equally in the regulation of dimorphic transition. We also show that the expression of YlRAS2 was increased dramatically at the transcriptional level during yeast-to-hypha transition, consistent with a major role of YlRas2 in the regulation of dimorphic transition. YlRas2's function in dimorphic transition depends on the active GTP-bound form of YlRas2 and its localization to the plasma membrane. YlRas2 could also partially function on the endomembranes. In addition, we identified the transcription factor Mhy1 as a potential signal transducer downstream of YlRas2 in the control of dimorphic transition. This finding suggests that novel signaling pathway controlled by Ras proteins regulating dimorphic transition may exist in Y.lipolytica.