CELL FUNCTION AND PI-5 KINASE REGULATION BY RHO

Rho GTP结合蛋白已经显示出调节 肌动蛋白应力纤维和局灶性粘连，以及Rho功能已被 参与细胞运动的调节。 我们已经证明Rho能够 通过调节细胞内PIP 2的活性来调节细胞内PIP 2的水平， 新型PI-5激酶。我们已经进一步确定，Rho活动是 正常细胞对生长因子的反应所必需的，并且可能是 转化细胞的锚定非依赖性生长的关键组分。 Rho似乎是粘附和增长的关键集成商 信号通路 我们在这项研究中提出，以确定PI-5激酶的意义， Rho对基本细胞功能的调节。我们将调查 上游调控Rho激活的机制 使用瞬时和稳定转染表达Rho/Ras的激活剂 突变体，并评估对PI-5激酶，细胞骨架和其他 信号.我们将纯化和表征PI-5激酶， 关于Rho这种蛋白质将作为一种有用的手段来验证假设 关于PIP 2在各种细胞过程中的作用。下游 将探索Rho调节PIP 2水平的结果。 这将包括检查肌动蛋白聚合，生长因子 反应性和调节磷脂酶D活性。从长远 我们的目标是了解细胞功能，特别是 免疫细胞，是由GTP结合蛋白控制的， 家人目前的研究应导致新的见解复杂 细胞生长、转化和粘附之间的关系， 与肿瘤的发展和所涉及的事件特别相关 在肿瘤转移中。

The Rho GTP-binding proteins have been shown to regulate the assembly of actin stress fibers and focal adhesions, and Rho function has been implicated in regulation of cell motility. We have shown that Rho is able to regulate the cellular levels of PIP2 by modulating the activity of a novel PI-5 kinase. We have further established that Rho activity is necessary for normal cellular responsiveness to growth factors, and may be a critical component of anchorage-independent growth of transformed cells. Rho appears to be poised as a critical integrator of adhesion and growth signaling pathways. We propose in this study to determine the significance of PI-5 kinase regulation by Rho for basic cellular function. We will investigate the mechanisms involved in the control of Rho activation by upstream activators using transient and stable transfection to express Rho/Ras mutants and evaluate effects on PI-5 kinase, the cytoskeleton, and other signals. We will purify and characterize the PI-5 kinase that is regulated by Rho. This protein will serve as a useful means to validate hypotheses about the role of PIP2 in various cellular processes. The downstream consequences of the regulation of PIP2 levels by Rho will be explored. This will include examination of actin polymerization, growth factor responsiveness, and regulation of phospholipase D activity. In the long term, our goal is to understand how cellular function, particularly that of immune cells, is controlled by the GTP-binding proteins of the who family. The current studies should lead to new insights into the complex relationship between cell growth, transformation, and adhesion, with particular relevance to the development of tumors and the events involved in tumor metastasis.