Analysis of MAP kinase cascades in S. cerevisiae

描述（由申请人提供）：细胞通常通过利用丝裂原激活蛋白（MAP）激酶级联来调节负责适当细胞反应的基因的表达，从而对环境信号做出反应。我打算进行的实验旨在加深对细胞如何感知环境压力、激活适当的 MAP 激酶级联，然后在细胞做出反应后停用级联的理解。氮饥饿通过 MAP 激酶级联诱导酿酒酵母中假菌丝的形成，该级联与高细胞外渗透压触发的 MAP 激酶级联共享成分。 Herskowitz 实验室的研究表明，Sho1p 除了作为渗透压传感器的既定作用之外，还可以作为氮饥饿的潜在传感器。我将进行基因筛选，以鉴定参与感知低氮的其他蛋白质。此外，我将研究如何调节 Sho1p 信号传导以防止高渗透性甘油和假菌丝生长途径的组成型激活。最后，将 MAPK Hog1p 的化学抑制版本与 DNA 微阵列结合使用，我将识别在应激和非应激条件下受 Hog1p 调节的基因。

DESCRIPTION (provided by applicant): Cells often respond to environmental cues by utilizing mitogen-activated protein (MAP) kinase cascades to regulate the expression of genes responsible for the appropriate cellular response. The experiments that I am proposing to conduct seek to advance the understanding of how cells sense environmental stress, activate the appropriate MAP kinase cascade, and then deactivate the cascade once the cell has responded. Nitrogen starvation induces the formation of pseudohyphae in S. cerevisiae via a MAP kinase cascade that shares components with a MAP kinase cascade triggered by high extracellular osmolarity. Studies from the Herskowitz lab have identified Sho1p as a potential sensor for nitrogen starvation in addition to its established role as a sensor of osmolarity. I will carry out genetic screens to identify other proteins involved in sensing low nitrogen. In addition, I shall investigate how Sho1p signaling is regulated to prevent constitutive activation of the high osmolarity glycerol and pseudohyphal growth pathways. Finally, using chemically inhibitable versions of the MAPK Hog1p in conjunction with DNA microarrays, I will identify genes regulated by Hog1p during both stress and non-stress conditions.