REGULATION OF GLYCEROPHOSPHOINOSITOL TRANSPORT IN YEAST

描述（申请人的摘要）：磷脂酶介导的 磷脂酰肌醇（P1）产生细胞外甘油磷酸肌醇 （GroPIns）是S.酿酒酵母细胞生长在 含肌醇的培养基。在肌醇限制的时代，GroPlns是 在需要能量的过程中被转运回细胞， GIT1基因的产物。这种新型的膜透性酶具有许多 有趣的特征，使其值得深入研究。Gitip是第一个 在任何生物体中都有基因转运体的特征，并且有证据表明 在高等真核生物中存在这样的转运蛋白。The GroPlns 通过Gitlp运输的用于合成PT及其 含有肌醇的衍生物，其中许多在信号传导中起重要作用 转导因此，Gitip的活动可能会影响到一些 重要的细胞事件。此外，有证据表明， GroPlns通过Gitip的表达受磷脂代谢和 磷酸盐代谢提出了表征调控的前景， 将细胞代谢的这两个基本方面联系起来的网络， 关于Gitip的研究最后，GIT 1的独特染色体位置 提供了一个机会，研究转录沉默的作用， 调节GIT1表达。本提案的具体目的是审查 通过Gitip在转录和转录水平调节GroPlns转运， 翻译后水平通过1）磷脂代谢，2）未折叠蛋白 反应途径，3）磷酸盐代谢，和4）基因定位。

DESCRIPTION (Applicant's abstract): The phospholipase-mediated deacylation of phosphatidylinositol (P1) to produce extracellular glycerophosphoinositol (GroPIns) is a major catabolic pathway in S. cerevisiae cells grown in inositolcontaining medium. In times of inositol limitation, GroPlns is transported back into the cell in an energy requiring process mediated by the product of the GIT1 gene. This novel membrane permease has a number of interesting features that make it worthy of intensive study. Gitip is the first GroPlns transporter to be characterized in any organism, and there is evidence for the existence of such a transporter in higher eukaryotes. The GroPlns transported through Gitlp is used for the synthesis of PT and its inositol-containing derivatives, many of which play important roles in signal transduction. Thus, the activity of Gitip may impinge upon a number of important cellular events. In addition, evidence suggesting that the transport of GroPlns through Gitip is regulated by both phospholipid metabolism and phosphate metabolism raises the prospect of characterizing the regulatory networks linking these two fundamental aspects of cellular metabolism by means of the study of Gitip. Finally, the unique chromosomal location of GIT1 provides an opportunity to study the role of transcriptional silencing in regulating GIT1 expression. The Specific Aims of this proposal are to examine the regulation of GroPlns transport through Gitip at the transcriptional and posttranslational levels by 1) phospholipid metabolism, 2) the Unfolded Protein Response Pathway, 3) phosphate metabolism ,and 4) gene location.