Yeast pseudohyphal growth is regulated by GPA2, a G protein α homolog
Yeast pseudohyphal growth is regulated by GPA2, a G protein α homolog
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DOI：
10.1093/emboj/16.23.7008
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发表时间：
1997-12-01
期刊：
影响因子：
11.4
通讯作者：
Heitman, J
中科院分区：
文献类型：
--
作者：
Lorenz, MC;Heitman, J
假菌丝分化是酵母芽殖过程中受氮饥饿诱导的一种丝状生长形式，氮限制调控这一过程的机制目前尚不清楚，我们发现酵母中两个异源三聚体G蛋白a亚基同源物之一GPA2调控假菌丝分化。Delta gpa2/Delta gpa2突变菌株在假菌丝生长方面存在缺陷，相比之下，即使在富氮培养基上，gpa2的组成型活性等位基因也能刺激丝状纤维的形成，此外，野生型菌株的显性阴性gpa2等位基因抑制丝状纤维的形成。一些研究结果，包括显性分析和报告基因研究，表明gpa2不调节已知的调节丝状纤维生长的MAP激酶级联反应。先前的研究表明GPA2与细胞内cAMP水平的控制有关；我们发现显性RAS2（Gly19Val）突变体或外源cAMP的表达抑制了δ gpa2假菌丝缺陷，即使在没有氮饥饿的情况下，cAMP也会刺激缺乏cAMP磷酸二酯酶PDE2的菌株的丝化。我们的研究结果表明，gpa2是通过调节cAMP水平来调节假菌丝分化的氮传感机制的一个元件。
Pseudohyphal differentiation, a filamentous growth form of the budding yeast Saccharomyces cerevisiae, is induced by nitrogen starvation, The mechanisms by which nitrogen limitation regulates this process are currently unknown, We have found that GPA2, one of the two heterotrimeric G protein a subunit homologs in yeast, regulates pseudohyphal differentiation. Delta gpa2/Delta gpa2 mutant strains have a defect in pseudohyphal growth, In contrast, a constitutively active allele of GPA2 stimulates filamentation, even on nitrogen-rich media, Moreover, a dominant negative GPA2 allele inhibits filamentation of wild-type strains, Several findings, including epistasis analysis and reporter gene studies, indicate that GPA2 does not regulate the MAP kinase cascade known to regulate filamentous growth, Previous studies have implicated GPA2 in the control of intracellular cAMP levels; we find that expression of the dominant RAS2(Gly19Val) mutant or exogenous cAMP suppresses the Delta gpa2 pseudohyphal defect, cAMP also stimulates filamentation in strains lacking the cAMP phosphodiesterase PDE2, even in the absence of nitrogen starvation, Our findings suggest that GPA2 is an element of the nitrogen sensing machinery that regulates pseudohyphal differentiation by modulating cAMP levels.