Regulation of ADP-ribosylation factor

ADP-核糖基化因子的调节

• 批准号: 7337945
• 负责人: Paul A Randazzo
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7337945
• 关键词: Regulation; ADP; ribosylation; factor

Coordinated membrane and actin remodeling are integral to a number of cellular functions, including (i) cell movement, (ii) endocytosis and exocytosis, and (iii) mitosis and are central to pathological processes such as tumor cell invasion and metastasis. A number of signaling molecules that control either or both membrane and actin remodeling include phosphoinositides, Arf family GTP-binding proteins and Rho family GTP-binding proteins. The main objective of the work in our laboratory is to elucidate the mechanisms that regulate signals mediated by Arf family proteins. The work has led to the identification of a family of Arf GTPase-activating proteins, the AZAPs, that may integrate at least four signaling pathways, providing coordinated responses in membranes and actin necessary for complex cellular behaviors. The AZAPs are comprised of four subfamilies: ASAP1/2/3, ACAP1/2/3, AGAP1/2/3 and ARAP1/2/3. Studies with two general goals are being conducted. One emphasis of the laboratory is to examine specific molecular mechanisms by which Arf GAPs interact with Arf and regulate Arf function. In these studies, we will determine (i) the interfaces between Arfs and GAPs; (ii) the interfaces between Arfs and coat proteins; (iii) the catalytic mechanism leading to GTP hydrolysis; (iv) mechanisms regulating GAP activity; and (v) functional interactions among Arfs, GAPs and Arf effectors including coat proteins. Studies to date have led us to propose (i) a new paradigm for the molecular mechanism by which Arf regulates cargo sorting and membrane trafficking, and (ii) an effector function for Arf GAPs of the AZAP family. Ongoing studies include testing these hypotheses and examining Arf GAPs as targets of signaling through tyrosine kinases and phosphoinositides. A second emphasis of the laboratory is an examination of the specific cellular sites of action of AZAP family members. This aim is closely related to the first. Using several strategies we have been determining the site of action for representative Arf GAPs. We have found specific membrane trafficking compartments regulated by some Arf GAPs. For instance, AGAP1 regulates AP-3 endosomes. We have also found that specific cytoskeletal structures are regulated by other Arf GAPs. For instance, ASAP1 regulates focal adhesions. We are currently examining the specific mechanisms that maintain and regulate Arf GAPs at specific sites, and exploring hypotheses about how the membrane trafficking sites may be related to the cytoskeletal sites. The most recent hypotheses that we are currently testing are (i) that Arf GAPs are in the Rho family signaling pathway with some Arf GAPs functioning as Rho effectors and (ii) Arf GAPs are targets of Src that are of crucial importance for the formation of podosomes and their pathologic analogs invadopia.

协调的膜和肌动蛋白的重塑是许多细胞功能不可或缺的，包括（i）细胞运动，（ii）内吞和胞吐作用，以及（iii）有丝核，是病理学过程（例如肿瘤细胞侵袭和转移）的核心。控制膜或肌动蛋白重塑的许多信号分子包括磷酸肌醇，ARF家族GTP结合蛋白和Rho家族GTP结合蛋白。我们实验室工作的主要目的是阐明调节由ARF家族蛋白介导的信号的机制。这项工作导致鉴定了ARF GTPase激活蛋白家族的AZAP，该蛋白可能至少整合了四个信号通路，从而在膜中提供了协调的反应，并为复杂的细胞行为提供了必要的肌动蛋白。 AZAP由四个亚家族组成：ASAP1/2/3，ACAP1/2/3，AGAP1/2/3和ARAP1/2/3。正在进行两个一般目标的研究。实验室的一种重点是检查ARF GAP与ARF相互作用并调节ARF功能的特定分子机制。在这些研究中，我们将确定（i）ARF和间隙之间的界面； （ii）ARF和大衣蛋白之间的界面； （iii）导致GTP水解的催化机制； （iv）调节间隙活性的机制； （v）包括外套蛋白在内的ARF，GAPS和ARF效应子之间的功能相互作用。迄今为止的研究使我们提出了（i）分子机制的新范式，ARF调节货物分类和膜运输，以及（ii）AZAP家族ARF间隙的效应函数。正在进行的研究包括测试这些假设并检查ARF间隙作为通过酪氨酸激酶和磷酸肌醇的信号传导的靶标。实验室的第二个重点是检查AZAP家族成员的特定细胞作用部位。这个目标与第一个目标密切相关。使用几种策略，我们一直在确定代表性ARF间隙的作用部位。我们发现特定的膜贩运室由某些ARF差距调节。例如，AGAP1调节AP-3内体。我们还发现，特定的细胞骨架结构受其他ARF间隙调节。例如，ASAP1调节焦点粘连。我们目前正在研究在特定地点维持和调节ARF间隙的特定机制，并探讨有关膜运输位点如何与细胞骨架位点有关的假设。我们目前正在测试的最新假设是（i）ARF间隙位于RHO家族信号通路中，某些ARF差距作为RHO效应子起作用，并且（ii）ARF GAPS是SRC的靶标，对于Podosomes及其病理类似物Invadopia的形成至关重要。