The PAK4 kinase in cell growth and transformation

PAK4 激酶在细胞生长和转化中的作用

• 批准号: 6823374
• 负责人: AUDREY G MINDEN
• 金额: $ 32.6万
• 依托单位: COLUMBIA UNIV NEW YORK MORNINGSIDE
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-01 至 2009-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6823374
• 关键词: SDS polyacrylamide gel electrophoresis; autoradiography; biological signal transduction; cell cycle; cell growth regulation; cell proliferation; cell senescence; enzyme activity; enzyme induction /repression; gel electrophoresis; guanine nucleotide binding protein; guanosinetriphosphatase activating protein; immunoprecipitation; laboratory mouse; mitogen activated protein kinase; neoplastic transformation; phosphorylation; protein structure function; serine threonine protein kinase; transfection; western blottings; yeast two hybrid system

DESCRIPTION (provided by applicant): The goal of the proposed experiments is to determine how the serine/threonine kinase Pak4 functions in the regulation of cell growth and transformation. Pak4 is an effector of the Rho GTPases Cdc42 and Rac, and was originally identified as a protein that functions in cytoskeletal organization. More recently, Pak4 was also shown to have important roles in controlling cell growth and survival. Pak4 is overexpressed in cancer cell lines, and Pak4 is highly transforming in established immortalized cell lines. In contrast, in primary cells Pak4 has a completely different function and triggers premature senescence rather than increased growth. In both respects Pak4 is similar to strong oncogenes such as oncogenic Ras, which are highly transforming in immortalized cells but inhibit growth in primary cells. Studying the role for Pak4 in cell growth is very important for understanding how Pak4 and Rho GTPases are associated with oncogenic transformation. The experiments in this proposal will take advantage of Pak4 null fibroblasts that have been generated in our lab, in order to study Pak4's role in the regulation of cell growth and transformation in immortalized cells, and premature senescence in primary cells. The following aims will be addressed: Aim 1.1. What role does Pak4 have in oncogenic transformation? Immortalized Pak4 null and control fibroblasts will be used to test the hypothesis that Pak4 is essential for transformation by Rho GTPases and their activators. We will also study the signaling pathways involved in Pak4 mediated transformation. Aim 1.2. What role does Pak4 have in the control of cell proliferation? The control of cell proliferation and transformation are closely associated. Here we will use the immortalized Pak4 null fibroblasts to test the hypothesis that Pak4 is required for cell cycle entry and proliferation in response to Rho GTPases. We will also determine whether cell cycle regulatory proteins function downstream to Pak4 during cell cycle progression. Aim 2. What signaling pathways mediate Pak4 induced premature senescence in primary cells? We will first test the hypothesis that Pak4 induced senescence in primary ceils is mediated by the ERK MAP Kinase, leading to induction of cell cycle regulatory proteins and subsequent inhibition of cell growth. We will also test the hypothesis that cytoskeletal regulatory proteins play an important role in Pak4 induced senescence. Finally, we will also determine whether Pak4 is required for oncogene induced senescence.

描述（由申请人提供）：拟议的实验的目标是确定丝氨酸/苏氨酸激酶PAK4如何在细胞生长和转化调节中起作用。 PAK4是Rho GTPases CDC42和RAC的效应子，最初被鉴定为在细胞骨架组织中起作用的蛋白质。最近，还显示PAK4在控制细胞生长和存活中具有重要作用。 PAK4在癌细胞系中过表达，并且PAK4在已建立的永生细胞系中高度转化。相反，在原代细胞中，PAK4具有完全不同的功能，并且触发了早期衰老，而不是增加生长。在这两个方面，PAK4都类似于强大的致癌基因，例如致癌性RA，它们在永生的细胞中高度转化，但抑制了原代细胞的生长。研究PAK4在细胞生长中的作用对于理解PAK4和RHO GTPases如何与致癌转化相关。该提案中的实验将利用我们实验室中已经产生的PAK4无效成纤维细胞，以研究PAK4在不成熟细胞中细胞生长和转化的作用中的作用，以及原代细胞中的早期衰老。将解决以下目标：目标1.1。 PAK4在致癌转化中有什么作用？永生的PAK4 NULL和对照成纤维细胞将用于检验以下假设：PAK4对于通过Rho GTPases及其激活剂转化至关重要。我们还将研究PAK4介导的转化中涉及的信号通路。目标1.2。 PAK4在控制细胞增殖中有什么作用？细胞增殖和转化的控制密切相关。在这里，我们将使用永生的PAK4 NULL成纤维细胞来检验以下假设：PAK4对于响应Rho GTPase需要细胞周期进入和增殖所必需。我们还将确定细胞周期蛋白在细胞周期进展过程中是否在PAK4下游功能。 AIM 2。哪些信号通路介导PAK4诱导原代细胞中的过早衰老？我们将首先检验以下假设：PAK4诱导原代天花板衰老是由ERK MAP激酶介导的，从而导致细胞周期调节蛋白的诱导并随后抑制细胞生长。我们还将检验以下假设：细胞骨架调节蛋白在PAK4诱导的衰老中起重要作用。最后，我们还将确定是否需要PAK4才能诱导衰老。