The central role of the PACS family of proteins in cellular organization

背景许多蛋白质在细胞内的运动是由膜运输机制保证的。这种机制能够实现蛋白质的正确亚细胞定位，从而保证蛋白质履行其细胞功能。总体而言，膜运输维持细胞稳态。该提案以膜运输调节蛋白磷酸呋喃酸簇分选 (PACS) 1 和 2 为中心。PACS 蛋白与称为货物的多种细胞蛋白形成关键相互作用，并将后者运送到正确的亚细胞位置。 PACS-1 和 PACS-2 贩运事件的重要性和多样性证明了这些蛋白质在贩运中发挥的核心作用。事实上，PACS-1 运输与初级纤毛的形成、将活化分子递送至特定细胞区室以及将无活性前体蛋白转化为活性蛋白等功能有关。相反，PACS-2 运输事件可以在关键细胞事件期间发挥作用，例如维持细胞钙水平和调节细胞死亡途径。假设 我们假设 PACS 蛋白是细胞的中央组织者，通过协调多种蛋白质-蛋白质相互作用，使流动货物能够运输到精确的亚细胞区域。蛋白质的正确运输对于它们随后发挥其功能至关重要。我们进一步假设，定义 PACS：蛋白质相互作用的新功能将为定义 PACS 蛋白质在细胞组织中的核心作用提供重要的见解。进展 我的实验室已经确定了一种由 PACS-1 控制的新型贩运途径。该途径涉及将激素输送到特定的亚细胞位置，即致密核心分泌颗粒。此外，我的实验室已经定义了全系列的 PACS-1 和 PACS-2 相互作用伙伴，这揭示了 PACS 作用在细胞核中的意外集中。总的来说，我们将借助我们在上一个资助期间完善和开发的各种技术来研究这些机制。目的 阐明 PACS-1 和 PACS-2 在多种膜运输途径中的作用是本研究计划的首要目标。目标 1：定义 PACS-1 在将货物分类为致密核心分泌颗粒中的作用。目标 2：确定 PACS-1 在致密核心分泌颗粒分泌货物中的作用。目标 3：定义蛋白质-蛋白质相互作用以及 PACS-1 和 PAC-2 在细胞核中的作用 意义 这一基于发现的研究计划将解决有关由中央膜运输调节因子 PACS 蛋白质控制的途径的重要且独特的问题。我们的长期计划集中于探索我们在上一个资助期间发现的全系列 PACS-1 和 PACS-2 货物。

Background The movement of many proteins within cells is ensured by the membrane trafficking machinery. This machinery enables the correct subcellular localization of proteins which guarantees proteins fulfill their cellular functions. Overall, membrane trafficking maintains cellular homeostasis. This proposal is centered on the membrane trafficking regulator proteins Phosphofurin Acid Cluster Sorting (PACS) 1 and 2. The PACS proteins form key interactions with multiple cellular proteins termed cargo and shuttle the latter cargo to the correct subcellular location. The importance and diversity of PACS-1 and PACS-2 trafficking events demonstrates the central role these proteins play in trafficking. Indeed, PACS-1 trafficking is implicated in the formation of primary cilia, the delivery of activating molecules to specific cellular compartments and the conversion of inactive precursor proteins to active proteins, amongst other functions. Conversely, PACS-2 trafficking events can function during key cellular events such as maintaining cellular calcium levels and modulating cellular death pathways. Hypothesis We hypothesize that PACS proteins are central organizers of the cell by orchestrating multiple protein-protein interactions to enable trafficking of itinerant cargo to precise subcellular locales. Proper trafficking of proteins is critical for them to subsequently perform their functions. We further hypothesize that defining how novel PACS:protein interactions function will shed significant insight into defining the central role of PACS proteins in cellular organization. Progress My laboratory has identified a novel trafficking pathway that is controlled by PACS-1. This pathway is implicated in the delivery of hormones to a specific subcellular location, the dense core secretory granule. In addition, my laboratory has defined the full range of PACS-1 & PACS-2 interacting partners which has revealed an unexpected concentration of PACS roles in the nucleus. Overall, we will study these mechanisms aided by a variety of techniques that we have perfected and developed during the previous funding period. Aims Elucidating the roles of PACS-1 & PACS-2 in multiple membrane trafficking pathways is the overarching aim of this research program. Aim1: Defining the role of PACS-1 in the sorting of cargo to dense core secretory granules. Aim 2: Defining the role of PACS-1 in the secretion of cargo from the dense core secretory granule. Aim 3: Defining the protein-protein interactions and roles of PACS-1 and PAC-2 in the nucleus Significance This discovery-based research program will address important and unique questions concerning the pathways that are governed by the central membrane trafficking regulator PACS proteins. Our long-term plans are centered on exploring the full range of PACS-1 and PACS-2 cargo that we have discovered during the previous funding period.