CHIMAERINS--RECEPTORS FOR DIACYLGLY AND PHORBOL ESTERS

Chimaerins——二酰基和佛波醇酯的受体

• 批准号: 2467303
• 负责人: MARCELO G. KAZANIETZ
• 金额: $ 19.95万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-30 至 2002-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2467303
• 关键词: 3T3 cells; SDS polyacrylamide gel electrophoresis; Sf9 cell line; autoradiography; diacylglycerols; electrospray ionization mass spectrometry; enzyme activity; enzyme induction /repression; growth factor receptors; immunocytochemistry; immunofluorescence technique; immunoprecipitation; isozymes; neoplastic transformation; phosphorylation; protein kinase C; receptor expression; second messengers; site directed mutagenesis; thin layer chromatography; tumor promoters; western blottings

DESCRIPTION: Although it is well established that receptor-mediated elevation in diacylglycerol (DAG) levels leads to activation of protein kinase C (PKC), a novel receptor for this lipophilic second messenger and its analogs, the phorbol ester tumor promoters, was recently discovered: chimaerin. In contrast to PKC, N-chimaerin does not possess a kinase domain. Its catalytic domain has high homology to BCR (breakpoint cluster region), a protein involved in Philadelphia chromosome translocation in chronic myelogenous leukemia. Like BCR, n-chimaerin has GTPase-activating protein (GAP) activity for the p21Rac, a small GTP-binding protein which plays a central role in cytoskeletal structure, gene transcription, cell growth and malignant transformation. The expansion of the chimaerin family with the cloning of new isoforms (a1- or "n-",a2-,b1-,andb2-chimaerins) indicates that a high degree of complexity may exist in the downstream pathways triggered by DAG. The fact that the a2- and b2-chimaerins possess SH2 motifs on their structure predicts that these chimaerin isoforms may associate with tyrosine phosphorylated proteins which may regulate their activity or localization, therefore suggesting crosstalk between different signaling pathways. The overall goal of this proposal is to evaluate whether the second messenger DAG and the phorbol ester tumor promoters regulate the chimaerin activity in addition to that of PKC, and to determine the biological consequences of the activation of this pathway in the cell. In Specific Aim 2, he will identify proteins that associate to chimaerins. The SH2 domains of a2- and 2-chimaeri withphosphotyrosine proteins. We will also study whether translocation induced by phorbol esters leads to the association of chimaerins with specific targets or anchoring proteins. In Specific Aim 3 he will focus on the biological roles of chimaerins. Our hypothesis is that chimaerins may affect those responses mediated by p21Rac, and therefore affect cell growth, malignant transformation, and cell morphology.Dr. Kazanietz's research has the potential for defining new "PKC independent" pathways for the phorbol ester tumor promoters and DAG, and hopefully will yield new insights into the events controlling malignant transformation. The characterization of the targets for the phorbol esters would be valuable to clarify their biological actions and also to unravel pathways involved in the mechanisms of carcinogenesis.

描述：虽然已经确定受体介导的 甘油二酯（DAG）水平升高导致蛋白质活化 激酶C（PKC），这种亲脂性第二信使的新型受体， 其类似物佛波醇酯肿瘤促进剂最近被发现： 嵌合体 与PKC相反，N-嵌合蛋白不具有激酶 域 其催化结构域与BCR（breakpoint cluster）具有高度同源性 区域），一种参与费城染色体易位的蛋白质， 慢性粒细胞白血病 与BCR一样，n-嵌合蛋白具有GTP酶激活作用， p21 Rac是一种小的GTP结合蛋白， 在细胞骨架结构、基因转录、细胞增殖、细胞分化、细胞凋亡等方面起着重要作用。 生长和恶性转化。 嵌合体家族的扩张 克隆新的同种型（a1-或“n-"、a2-、b1-和b2-嵌合蛋白） 表明下游可能存在高度复杂性 由达格触发的途径。 事实上，a2和b2嵌合体具有 它们结构上的SH 2基序预示着这些嵌合蛋白异构体可能 与酪氨酸磷酸化蛋白质相关， 活动或定位，因此表明不同 信号通路 本提案的总体目标是评估 第二信使DAG和佛波酯肿瘤促进剂 调节嵌合蛋白的活性，以及PKC的活性，并确定 细胞中这一途径激活的生物学后果。 在具体目标2中，他将鉴定与嵌合蛋白相关的蛋白质。 具有磷酸酪氨酸蛋白的α 2-和2-嵌合体的SH 2结构域。 我们将 还研究了佛波醇酯诱导的易位是否导致了 嵌合蛋白与特定靶点或锚定蛋白的结合。 在 具体目标3他将专注于嵌合体的生物学作用。 我们 假设嵌合蛋白可能影响p21 Rac介导的那些反应， 从而影响细胞生长、恶性转化和细胞 Kazanietz博士的研究有可能定义新的“PKC 佛波醇酯肿瘤促进剂和DAG的“独立”途径，和 希望能对控制恶性肿瘤的事件产生新的见解， 转型 佛波酯的靶点表征 将有助于阐明它们的生物学行为， 参与致癌机制的途径。