LIPID SIGNALLING IN THE CELL NUCLEUS

美国国际和平研究所长期以来一直对蛋白质的各个方面感兴趣 细胞内的激酶C(PKC)同工酶信号传导。PI之前已经 详细研究了一种特定的PKC同工酶，PKC B2，并产生了一种 关于周围环境的机制有相当多的知识 这种同工酶的激活。此FIRCA的当前父项目 应用程序现在已由PI转移到探索功能 人白血病细胞中非典型PKC同工酶PKCi的鉴定 生死存亡。在研究导致PKC B2核激活的因素时 在有丝分裂之前，PI的实验室从G2期分离出一个有核的PI-PLC 原子核。利用已知PI-PLC同工酶抗体的初步实验 表示这一核PI-PLC不对应于之前的任何 鉴定了PI-PLC同工酶。外国合作者，在与 再生的大鼠肝细胞，也观察到了一种新的核的存在 PI-PLC活性参与细胞周期调控。鉴于这些常见的发现 和利益，并考虑到外国合作者在 一种新的磷脂酰肌醇代谢酶的生化分析 这些调查人员之间出现了合作努力。因此， 这项建议的主旨是鉴定这种新的核PI-PLC活性。 此外，最近的数据表明，一种磷脂酰肌醇3-激酶(PI3K) 细胞核内存在信号系统，这种核PI3K信号 该系统不同于已描述的细胞质细胞膜PI3K 系统。新的核PI3K通路负责PKB的激活。这些 初步结果提示，PI3K和PKB的激活可能起到直接作用 在与细胞增殖和核事件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 扩展和确认这些关于核PI3K和PI3K的作用的初步结果 这些细胞事件中的PKB。

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.