REGULATION OF LYSOSOMAL ENZYME TRAFFICKING

溶酶体酶贩运的调控

• 批准号: 3235108
• 负责人: G. Gary Sahagian
• 金额: $ 16.92万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-01-01 至 1995-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3235108
• 关键词: biomarker; complementary DNA; enzyme mechanism; enzyme structure; growth factor; growth factor receptors; hormone regulation /control mechanism; laboratory rabbit; laboratory rat; lysosomes; mannose; phosphorylation; pinocytosis; protein transport; secretion; site directed mutagenesis; sugar phosphates

The lysosome plays an important role in eukaryotic cells as the primary site of degradation of both cellular and extracellular macromolecules. Selective delivery of proteins to the lysosome involves addition of a common address marker (the mannose 6-phosphate marker) to the proteins, and membrane-associated receptors that bind the marker and mediate translocation of the proteins to the lysosomal compartment. Recent studies suggest that under certain conditions this targeting process can be altered such that enzymes normally destined for lysosomes are secreted from the cell. This regulatory mechanism may be important physiologically since extracellular lysosomal enzymes may play important roles in tumor growth and metastasis as well as in normal cell growth. The long range goal of this proposal is to determine the molecular basis for normal and regulated trafficking of lysosomal enzymes. The proposed studies will involve molecular and cellular biological studies on MEP, a lysosomal cysteine proteinase whose trafficking is regulated by growth factors and cellular transformation, and the receptors thought to mediate lysosomal trafficking: the cation dependent mannose 6-phosphate (Man-6-P) receptor and the Man-6-P/IGF-II receptor. Site-specific mutagenesis and expression of MEP cDNA will be used to identify structural determinants on the protein responsible for addition of the Man-6-P marker. Analysis of the protein and carbohydrate portions of MEP, and examination of the effects of growth factors on the synthesis and trafficking of the two receptors, will be carried out in order to further define the basis for MEP's regulated secretion. These studies will provide information leading to determination of the recognition structure responsible for selective phosphorylation of lysosomal proteins and will help elucidate the mechanisms involved in regulated trafficking of lysosomal proteins.

溶酶体在真核细胞中发挥着重要作用，是细胞的主要细胞。 细胞和细胞外大分子的降解位点。 将蛋白质选择性递送至溶酶体涉及添加 蛋白质的共同地址标记（甘露糖 6-磷酸标记），以及 结合标记物并介导的膜相关受体 蛋白质易位至溶酶体区室。 最近的研究 表明在某些条件下可以改变这个目标过程 使得通常去往溶酶体的酶从 细胞。 这种调节机制可能在生理上很重要，因为 细胞外溶酶体酶可能在肿瘤生长中发挥重要作用 和转移以及正常细胞生长。 该提案的长期目标是确定分子基础 用于溶酶体酶的正常和调节运输。 拟议的 研究将涉及 MEP 的分子和细胞生物学研究， 溶酶体半胱氨酸蛋白酶，其运输受生长调节 因素和细胞转化，以及被认为介导的受体 溶酶体运输：阳离子依赖性甘露糖 6-磷酸 (Man-6-P) 受体和Man-6-P/IGF-II 受体。 MEP cDNA 的位点特异性诱变和表达将用于 确定负责添加的蛋白质的结构决定因素 Man-6-P 标记。 蛋白质和碳水化合物部分的分析 MEP，以及生长因子对合成和合成的影响的检查 将进行这两种受体的贩运，以进一步 定义 MEP 调节分泌的基础。 这些研究将提供信息，从而确定 负责选择性磷酸化的识别结构 溶酶体蛋白，将有助于阐明参与的机制 调节溶酶体蛋白的运输。