The first secreted Tyrosine kinase

第一个分泌型酪氨酸激酶

• 批准号: 9334892
• 负责人: MALCOLM R. WHITMAN
• 金额: $ 38.76万
• 依托单位: HARVARD MEDICAL SCHOOL
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-17 至 2019-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9334892
• 关键词: Area; Atherosclerosis; Blood Platelets; Cell Differentiation process; Cells; Chondrocytes; Dependence; Disease; Environment; Epiblast; Extracellular Matrix; Fibrosis; Goals; Health; HepG2; Homeostasis; Laboratories; Literature; Modification; Neoplasm Metastasis; Organ; Organogenesis; Pathologic; Pathology; Pathway interactions; Pattern; Pheochromocytoma; Phosphorylation; Phosphotransferases; Physiological; Protein Tyrosine Kinase; Proteins; Regulation; Reporting; Role; Site; Stimulus; Testing; Tissues; Tyrosine Phosphorylation; Tyrosine Phosphorylation Site; cell immortalization; cell type; extracellular; human disease; immortalized cell; in vivo; novel therapeutic intervention; protein function; public health relevance; response; tumor

 DESCRIPTION (provided by applicant): Broad and structurally conserved patterns of tyrosine phosphorylation in secreted proteins in vivo have been widely identified in the existing literature but the kinase(s) responsible for these phosphorylations have been obscure, precluding functional analyses of these modifications. Our laboratory has recently identified the first known secreted protein tyrosine kinase (VLK). VLK is first expressed in the early epiblast, and is essential for normal organogenesis. We find that VLK phosphorylates a wide range of secreted proteins with established roles in the regulation of secretion, extracellular matrix (ECM) formation, and ECM remodeling. In many cases, sites phosphorylated by VLK correspond to sites of tyrosine phosphorylation in secreted proteins previously found to occur in vivo. We have also found that, during stimulated platelet secretion, VLK is co-released with endogenous ATP to drive de novo tyrosine phosphorylation outside the cell. These finding open up a broad new area in the study of dynamic regulation of ECM and other secreted proteins. In this proposal, we plan to investigate the regulation of VLK within the secretory pathway, identify secreted targets for VLK phosphorylation in cells that express VLK endogenously, and begin to establish how VLK phosphorylation modifies the function of specific secreted or secretory pathway resident proteins. We will examine in detail the components necessary for regulation of VLK secretion and phosphorylation, both in platelets in response to physiological stimuli, and in immortalized cells that secrete VLK either constitutively or in response to stimuli. We will examine the phosphorylated secretome in each of these cell types, and the dependence of these phosphorylations on VLK. We will then build on this identification of physiological VLK substrates in differentiated cell types to establish how VLK modifies specific substrate functions. These studies will define a new mechanism for the dynamic regulation of the activity of proteins in the secretory pathway and in the extracellular environment.

 描述（由申请人提供）：现有文献中已广泛鉴定了体内分泌蛋白中酪氨酸磷酸化的广泛且结构保守的模式，但负责这些磷酸化的激酶一直不清楚，排除了对这些修饰的功能分析。我们的实验室最近发现了第一个已知的分泌型蛋白酪氨酸激酶（VLK）。 VLK 首先在早期外胚层中表达，对于正常的器官发生至关重要。我们发现 VLK 磷酸化多种分泌蛋白，并在分泌调节、细胞外基质 (ECM) 形成和 ECM 重塑中发挥确定的作用。在许多情况下，VLK 磷酸化的位点对应于先前发现体内发生的分泌蛋白中酪氨酸磷酸化的位点。我们还发现，在刺激血小板分泌过程中，VLK 与内源 ATP 共同释放，驱动细胞外酪氨酸从头磷酸化。这些发现为 ECM 和其他分泌蛋白的动态调节研究开辟了广阔的新领域。在本提案中，我们计划研究分泌途径中 VLK 的调节，确定内源表达 VLK 的细胞中 VLK 磷酸化的分泌靶点，并开始确定 VLK 磷酸化如何修改特定分泌或分泌途径驻留蛋白的功能。我们将详细检查调节 VLK 分泌和磷酸化所需的成分，无论是在响应生理刺激的血小板中，还是在组成型或响应刺激时分泌 VLK 的永生化细胞中。我们将检查每种细胞类型中的磷酸化分泌蛋白组，以及这些磷酸化对 VLK 的依赖性。然后，我们将基于分化细胞类型中生理 VLK 底物的鉴定，确定 VLK 如何修改特定底物功能。 这些研究将定义一种动态调节分泌途径和细胞外环境中蛋白质活性的新机制。