An autocrine repressor of cell proliferation

细胞增殖的自分泌抑制因子

• 批准号: 7104535
• 负责人: Richard H Gomer
• 金额: $ 28.72万
• 依托单位: RICE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-01 至 2010-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7104535
• 关键词: Dictyostelium; SDS polyacrylamide gel electrophoresis; antiserum; autocrine; biological signal transduction; cell growth regulation; cell proliferation; enzyme linked immunosorbent assay; gene expression; gene targeting; genetic recombination; genetic screening; growth inhibitors; immunologic substance development /preparation; immunoprecipitation; inhibitor /antagonist; laboratory rabbit; protein purification; protein structure; protein structure function; protozoal genetics; receptor; receptor binding

DESCRIPTION (provided by applicant): Many cells, including some tumor cells, appear to secrete autocrine factors that repress their proliferation. In most cases the factors and associated signal transduction pathways are unknown. The PI has found that growing Dictyostelium cells secrete a protein called AprA for autocrine proliferation repressor. AprA is a 60 kDa protein, is part of a secreted approximately 150 kDa complex, and has some similarity to bacterial and mammalian proteins of unknown function. Compared to wild-type cells, aprA null cells proliferate faster while AprA overexpressing cells proliferate slower. Furthermore, adding immunoprecipitated AprA to cells slows their proliferation. I propose three specific aims to elucidate the mechanisms by which AprA regulates cell proliferation. First, we will determine if the approximately 150 kDa factor contains AprA alone or AprA plus additional factors, by purifying this factor and identifying its components. Second, we will determine if our candidate receptor for this factor senses and binds this factor, or is part of a different pathway that inhibits proliferation. Third, we will identify downstream components that are required for the growth inhibitory action of this factor. In preliminary screens, we identified four suppressors of the slow-proliferation AprA overexpressor phenotype; one encodes a protein with similarity to CLN2, a gene implicated in juvenile neuronal ceroid lipofuscinosis, poorly differentiated tumors, and cardiac hypertrophy. We will make nulls of suppressor genes and determine if they are part of the AprA signal transduction pathway, or are part of a different mechanism that represses proliferation. Our identification of the aprA mutant and AprA protein has opened the way for the application of molecular and genetic analysis to the mechanism by which extracellular factors can inhibit proliferation. We anticipate that these studies will assist in understanding both how normal tissue and tumor growth are regulated in multicellular organisms, and may help lead to novel ways to repress tumor cell proliferation.

描述（由申请人提供）：许多细胞，包括某些肿瘤细胞，似乎分泌了抑制其增殖的自分泌因素。在大多数情况下，因素和相关的信号转导途径尚不清楚。 PI发现，生长的Dictyostelium细胞分泌一种称为APRA的蛋白质用于自分泌增生抑制剂。 APRA是60 kDa蛋白，是分泌约150 kDa复合物的一部分，与未知功能的细菌和哺乳动物蛋白具有一定的相似性。与野生型细胞相比，APRA无效细胞增殖速度更快，而APRA过表达细胞增殖较慢。此外，将免疫沉淀的APRA添加到细胞中减慢其增殖。我提出了三个特定的目的，以阐明APRA调节细胞增殖的机制。首先，我们将通过纯化此因子并识别其成分，确定大约150 kDa因子是否仅包含APRA或APRA以及其他因素。其次，我们将确定该因素的候选受体是否感官并结合此因子，还是抑制增殖的不同途径的一部分。第三，我们将确定该因素生长抑制作用所需的下游组成部分。在初步屏幕中，我们确定了慢速溶质APRA过表达表型的四个抑制因子。一个人编码与CLN2相似的蛋白质，该蛋白质与少年神经元蛋白脂肪促肌张力蛋白病，分化较差和心脏肥大有关。我们将使抑制基因的无效，并确定它们是APRA信号转导途径的一部分，还是抑制增殖的不同机制的一部分。我们对APRA突变体和APRA蛋白的鉴定为将分子和遗传分析应用于细胞外因子可以抑制增殖的机制开辟了道路。我们预计这些研究将有助于了解多细胞生物中正常组织和肿瘤生长如何受到调节，并可能有助于导致抑制肿瘤细胞增殖的新方法。