LIPID SIGNALLING IN THE CELL NUCLEUS

美国PI对蛋白质的各个方面都有着长期的兴趣 激酶C（PKC）同工酶信号传导。此前，PI 详细研究了一种特殊的pKC同工酶，PKC B2，并产生了一个 大量的知识，关于周围的机制 激活这种同工酶。本FIRCA的当前父项目 PI的应用程序现已转向探索功能 人白血病细胞非典型蛋白激酶C同工酶PKCi特性研究 生存在检查负责PKC B2核激活的因素时， 在有丝分裂之前，PI的实验室从G2期分离出核PI-PLC 原子核。使用已知PI-PLC同工酶的抗体的初步实验 表明，这种核PI-PLC不符合任何以前的 鉴定了PI-PLC同工酶。外国合作者在与 再生大鼠肝细胞，还观察到存在一种新的核 PI-PLC活性参与细胞周期调控。鉴于这些共同的发现 和利益，并考虑到外国合作者的专业知识， 磷脂酰肌醇代谢酶的生化分析，一种新的 这些调查人员之间产生了合作努力。因此 该建议的主要目的是鉴定这种新的核PI-PLC活性。 此外，最近的数据表明，磷脂酰肌醇3-激酶（PI 3 K） 信号系统存在于细胞核内，这种细胞核PI 3 K信号 系统不同于已充分描述的细胞质-细胞膜PI 3 K 系统新的核PI 3 K通路负责PKB活化。这些 初步结果表明，PI 3 K和PKB的激活可能在 在与细胞增殖相关的核事件中的生理作用， 细胞周期进程因此，第二和第三个具体目标建议： 扩展并证实了这些初步结果的作用，核PI 3 K和 PKB在这些细胞事件。

The U.S. PI has a long-standing interest in the various aspects of protein kinase C (PKC) isozyme signaling within cells. The PI has previously investigated in detail one particular pKC isozyme, PKC B2, and has generated a considerable amount of knowledge regarding the mechanisms surrounding activation of this isozyme. The present parent project for this FIRCA application by the PI has now shifted to explore the functional characterization of an atypical PKC isozyme, PKCi, in human leukemia cell survival. In examining factors responsible for the nuclear activation of PKC B2 prior to mitosis, the PI's laboratory isolated a nuclear PI-PLC from G2 phase nuclei. Preliminary experiments using antibodies to known PI-PLC isozymes indicated that this nuclear PI-PLC did not correspond to any of the previously identified PI-PLC isozymes. The foreign collaborator, while working with regenerating rat hepatocytes, also observed the presence of a novel nuclear PI-PLC activity involved in cell cycle regulation. Given these common findings and interests, and given the foreign collaborator's expertise in the biochemical analysis of phosphatidylinositol-metabolizing enzymes, a new collaborative effort has arisen between these investigators. Therefore, the main thrust of this proposal is to identify this novel nuclear PI-PLC activity. In addition, recent data suggests that a phosphatidylinositol 3-kinase (PI3K) signaling system exists within the nucleus and that this nuclear PI3K signaling system is distinct from the well described cytoplasmic-cell membrane PI3K system. The novel nuclear PI3K pathway is responsible for PKB activation. These preliminary results suggest that PI3K and PKB activation may play a direct physiologic role in nuclear events associated with cellular proliferation and cell cycle progression. The second and third specific aims therefore propose to expand and confirm these preliminary results of the roles of nuclear PI3K and PKB in these cellular events.