Dynamic Protein Palmitoylation in Cell Signaling

细胞信号转导中的动态蛋白质棕榈酰化

• 批准号: 9104881
• 负责人: Askar Akimzhanov
• 金额: $ 32.34万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-16 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9104881
• 关键词: Acyltransferase; Adaptor Signaling Protein; Biochemical; Biological; Biological Assay; Cardiovascular Diseases; Cell membrane; Complex; Cysteine; Disease; Enzymes; Event; Family; Family member; Golgi Apparatus; Homeostasis; Imaging Techniques; Immune System Diseases; Kinetics; Label; Liquid substance; Malignant Neoplasms; Mediating; Membrane Microdomains; Membrane Proteins; Modeling; Molecular; Pathogenesis; Pathway interactions; Physiological; Population; Post-Translational Protein Processing; Protein Dynamics; Protein S; Protein Tyrosine Kinase; Proteins; Receptor Signaling; Recruitment Activity; Regulation; Role; Signal Transduction; Signaling Molecule; Signaling Protein; Stimulus; Substrate Specificity; T Cell Receptor Signaling Pathway; T-Cell Activation; T-Cell Receptor; T-Lymphocyte; Testing; Transferase; base; live cell imaging; member; novel; palmitoylation; protein activation; protein function; public health relevance; research study; response; therapeutic target

 DESCRIPTION (provided by applicant): Although protein S-palmitoylation was discovered more than 30 years ago and palmitoylated proteins have been implicated in pathogenesis of several diseases including cancer, cardiovascular and immune disorders, it remains one of the most understudied post-translational protein modifications. High lability, one of the key features of protein palmitoylation, along with its prominent effect on the protein function makes it an attractive mechanism for the regulation of intracellular signaling. In particular, rapid changes in protein palmitoylation could provide a molecular basis for activation of the plasma membrane-localized signaling proteins by targeting them into specific plasma membrane subdomains. It has been established that activation of the T cell receptor (TCR) signaling pathway is critically dependent on palmitoylation of signaling proteins and their functional association with the liquid ordered plasma membrane subdomains ("lipid rafts") in a palmitoylation-dependent manner. However, molecular mechanisms regulating T cell signaling protein palmitoylation and lipid raft partitioning remain largely unknown. In our preliminary experiments we found that physiologically relevant stimulation of the TCR complex leads to rapid increase in palmitoylation of the tyrosine kinase Lck which is detectable within minutes upon engagement of TCR. To interpret this finding, we propose a model in which the TCR complex recruits and activates plasma membrane associated palmitoyl acyltransferases (PATs) to increase palmitoylation and plasma membrane compartmentalization of T cell signaling proteins. We will investigate this hypothesis in two Specific Aims. In Aim 1 we will determine the role of rapid stimulus-dependent protein palmitoylation in activation of the TCR signaling pathway. We will analyze the dynamics and regulation of stimulus-dependent palmitoylation of Lck, LAT and other members of the TCR signaling pathway. In Aim 2 we will determine if plasma membrane-localized PATs mediate T cell activation. This Aim will potentially uncover a previously uncharacterized role of DHHC PATs in regulation of T cell signaling. Overall, we expect that implementation of a novel class of regulatory enzymes into the canonical TCR signaling pathway would greatly expand a range of potential therapeutic targets for diseases associated with altered T cell homeostasis.

 描述（由申请人提供）：尽管蛋白质 S-棕榈酰化在 30 多年前就被发现，并且棕榈酰化蛋白质与癌症、心血管和免疫疾病等多种疾病的发病机制有关，但它仍然是研究最多的翻译后蛋白质修饰之一。高不稳定性是蛋白质棕榈酰化的关键特征之一，加上其对蛋白质功能的显着影响，使其成为细胞内信号传导调节的有吸引力的机制。特别是，快速变化 蛋白质棕榈酰化可以通过将质膜定位信号蛋白靶向特定的质膜子结构域，为激活质膜定位信号蛋白提供分子基础。已经确定，T 细胞受体 (TCR) 信号通路的激活关键依赖于信号蛋白的棕榈酰化及其以棕榈酰化依赖性方式与液体有序质膜子结构域（“脂筏”）的功能关联。然而，调节 T 细胞信号蛋白棕榈酰化和脂筏分配的分子机制仍然很大程度上未知。在我们的初步实验中，我们发现 TCR 复合物的生理相关刺激会导致酪氨酸激酶 Lck 的棕榈酰化快速增加，在 TCR 参与后几分钟内即可检测到。为了解释这一发现，我们提出了一个模型，其中 TCR 复合物招募并激活质膜相关的棕榈酰酰基转移酶 (PAT)，以增加 T 细胞信号蛋白的棕榈酰化和质膜区室化。我们将在两个具体目标中研究这一假设。在目标 1 中，我们将确定快速刺激依赖性蛋白棕榈酰化在 TCR 信号通路激活中的作用。我们将分析 Lck、LAT 和 TCR 信号通路其他成员刺激依赖性棕榈酰化的动态和调节。在目标 2 中，我们将确定质膜定位的 PAT 是否介导 T 细胞激活。这一目标将有可能揭示 DHHC PAT 在 T 细胞信号传导调节中先前未表征的作用。总体而言，我们预计，在经典 TCR 信号通路中应用一类新型调节酶将极大地扩展与 T 细胞稳态改变相关疾病的一系列潜在治疗靶点。