The TRPML1 Role in Lysosomes

TRPML1 在溶酶体中的作用

• 批准号: 7651968
• 负责人: KIRILL KISELYOV
• 金额: $ 24.93万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7651968
• 关键词: Acute; Affect; Biochemical; Biological Assay; Cations; Cell membrane; Cells; Code; Cognitive; Cornea; Data; Developmental Delay Disorders; Disease; Down-Regulation; Environment; Enzymes; Event; Fibroblasts; Future; Ganglioside Sialidase Deficiency Disease; Gangliosides; Genes; Homeostasis; Hydrolysis; Intracellular Membranes; Ion Channel; Ions; Lipids; Longevity; Lysosomal Storage Diseases; Lysosomes; Membrane; Membrane Fusion; Membrane Potentials; Membrane Protein Traffic; Metabolic; Metabolism; Metals; Modeling; Molecular; Mutate; Mutation; Nature; Organelles; Pathogenesis; Pathway interactions; Patients; Permeability; Phenotype; Phospholipids; Physiological; Property; Proteins; Quality of life; Regulation; Relative (related person); Retinal Degeneration; Role; Severities; Small Interfering RNA; Structure; System; Techniques; Test Result; Testing; Time; Work; comparative; disability; enzyme replacement therapy; gene function; lipid transport; member; novel; protein degradation; receptor; research study; trafficking

Project summary. Mucolipidosis type IV (MLIV) is a lysosomal storage disorder caused by mutations in the gene coding for a lysosomal ion channel Mucolipin 1 (TRPML1). MLIV causes severe developmental delays, psychomotor retardation, cognitive disabilities, corneal cloudiness and degeneration of the retina. At the cellular level, accumulation of phospholipids and gangliosides is detected, and virtually all patients’ cells contain enfolded membranous structures of unknown origin. Since TRPML1 localizes in lysosomes and its downregulation causes severe lysosomal storage phenotype, TRPML1 was suggested to regulate lysosomal function. At present, there is no complete model that explains TRPML1 function in the lysosomes. TRPML1 was suggested to directly regulate intracellular membrane traffic by modulating fusion and/or fission of the organelles within the lower portions of the endocytic pathway. An alternative model suggests that TRPML1 affects lysosomal hydrolysis by regulating lysosomal acidification. The present project aims to directly answer the two main question in MLIV pathogenesis: whether TRPML1 directly regulates membrane traffic in the endocytic pathway and which aspect of TRPML1 permeability makes it indispensable for the proper function of the endocytic pathway. This will be accomplished by a combination of molecular, biochemical and physiological techniques. Specifically, an siRNA driven TRPML1 downregulation system will be used to establish the direct and immediate effects of TRPML1 downregulation on membrane traffic and lysosomal lipid hydrolysis. A structure function analysis of ion permeation through TRPML1 and its close relative TRPML3 will be performed to identify the structural determinants of the unique aspects of TRPML1 ion permeation. The ion permeation through TRPML1 will be specifically modulated in order to establish the aspects of TRPML1 permeability that make TRPML1 indispensable for the proper function of the endocytic pathway. The experiments planned in this proposal will establish the direction for the search for MLIV treatments, identify the new roles for intracellular ion channels in regulation of membrane traffic, lysosomal metabolism and organellar ion homeostasis and provide novel structural information regarding the basic mechanisms of ion channel permeation, rectification and block.

项目摘要。 IV型粘脂脂异常（MLIV）是由基因突变引起的溶酶体储存障碍 编码溶酶体离子通道粘膜1（TRPML1）。 MLIV引起严重的发展 延迟，心理运动迟缓，认知障碍，角膜云和变性 视网膜。在细胞水平上，检测到磷脂和神经节苷脂的积累，并且 几乎所有患者的细胞都包含未知来源的膜结构。自从 TRPML1定位于溶酶体及其下调导致严重的溶酶体储存 建议表型，TRPML1调节溶酶体功能。目前，没有 完整的模型，解释了溶酶体中TRPML1功能。建议TRPML1 通过调节融合和/或裂变，直接调节细胞内膜流量 内吞途径下部的细胞器。一个替代模型建议 TRPML1通过调节溶酶体酸化会影响溶酶体水解。现在 项目旨在直接回答MLIV发病机理中的两个主要问题：是否trpml1 直接调节内吞途径中的膜流量以及TRPML1的哪个方面 渗透性使得内吞途径的正常功能必不可少。这会 可以通过分子，生化和物理技术的结合来完成。 具体而言，将使用siRNA驱动器TRPML1下调系统来建立 TRPML1下调对膜流量和溶酶体的直接和直接影响 脂质水解。通过TRPML1及其关闭的离子渗透的结构函数分析 将执行相对TRPML3以识别独特方面的结构决定剂 trpml1离子渗透。通过TRPML1的离子渗透将被专门调节 为了建立TRPML1渗透性的各个方面，使Trpml1不可或缺 内吞途径的正确功能。该提议中计划的实验将 建立寻找MLIV治疗的方向，确定细胞内的新作用 膜流量，溶酶体代谢和细胞器离子调节的离子通道 稳态并提供有关离子基本机制的新结构信息 通道渗透，矫正和阻塞。