Regulation of ADP-ribosylation factor

ADP-核糖基化因子的调节

• 批准号: 6558993
• 负责人: P 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/6558993
• 关键词: ADP ribosylation; binding proteins; biological signal transduction; genetic regulation; guanine nucleotide binding protein; guanosinetriphosphatase activating protein; phosphorylation; protein purification; protein structure function; protein transport

Coordinated membrane actin remodeling are integral to a number of cellular functions including (i) cell movement, (ii) endocytosis and exocytosis and (iii) mitosis. 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 the signals mediated by Arf family proteins. The work has led to the identification of a family of Arf GTPase-activating proteins, the ASAPs, that may integrate at least four signaling pathways, providing coordinated responses in membranes and actin necessary for particular cellular behaviors. The ASAPs are comprised of four subfamilies: ASAP1/2, 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 impact Arf activities. We have found that the PH domain of one Arf GAP, ASAP1, is an allosteric site regulating catalysis through the Arf GAP domain. In those studies, we also found that ASAP1 contains localization domains that function independently of the PH domain. Using the coat adaptor protein, GGA, as a model, we have also found that interaction of Arf GAP with Arf requires that Arf dissociate from its effector proteins. Based on these data, we have proposed that Arf GAPs bind to the site of Arf action, and senses, through changes in the lipid environment for instance, when Arf should be inactivated. Continuing studies are designed to define the site of interaction between Arf and Arf GAP as well as between Arf and GGA. In addition, we are examining the potential role of Arf GAP - Arf interactions in cargo sorting that occurs during membrane trafficking events such as protein secretion and exocytosis. A second emphasis of the laboratory is an examination of the specific cellular roles of ASAP family members. We have started by examining representative members of each subfamily. ASAP1 has been found to localize to and control the turnover of focal adhesion, structures that anchor cells to the substratum and which must be remodeled for cell movement to occur. ACAP1 has been found to regulate Arf6 dependent actin-rich protrusion formation, an event thought to be involved in cell spreading and movement. ARAP1 has been also found to regulate both membrane trafficking and the actin cytoskeleton, functioning as a node in a signaling network that regulates cell movement. PIP3 binds to ARAP1, activating the Arf GAP, thereby inactivating Arf and controlling Golgi function. In addition, ARAP1 both induces the activation of Cdc42 and the inactivation of Rho. Reciprocal regulation of these two proteins has been found to induce cell migration. Therefore, in general the ASAP family of Arf GAPs appear to regulate events involved in cell migration. Continuing studies are designed to (i) further delineate the role of Arf GAPs in signaling, (ii) identify specific biological events dependent on signaling through Arf GAPs, eg. Development and function of immunological cells and (iii) evaluate a possible involvement in pathological processes, particularly tumor cell invasion and metastasis. Z01 BC 07365-03 LBC to LCO

协调的膜肌动蛋白重塑是许多细胞功能的组成部分，包括（i）细胞运动，（ii）内吞和胞吐作用和（iii）有丝分裂。许多控制膜和肌动蛋白重塑之一或两者的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。本实验室工作的主要目的是阐明调节Arf家族蛋白介导的信号的机制。这项工作已经导致了一个家庭的Arf GTP酶激活蛋白，ASAP，可能整合至少四个信号通路，提供协调的反应，在膜和肌动蛋白所需的特定细胞行为的鉴定。ASAP由四个亚家族组成：ASAP 1/2，ACAP 1/2/3，AGAP 1/2/3和ARAP 1/2/3。目前正在进行有两个总目标的研究。 该实验室的一个重点是研究Arf GAP与Arf相互作用并影响Arf活性的特定分子机制。我们已经发现，PH结构域的一个Arf GAP，ASAP 1，是一个变构网站调节催化通过Arf GAP结构域。在这些研究中，我们还发现ASAP 1包含独立于PH结构域发挥功能的定位结构域。使用外套衔接蛋白，GGA，作为一个模型，我们还发现，Arf GAP与Arf的相互作用需要Arf从其效应蛋白解离。基于这些数据，我们提出Arf GAP结合到Arf作用的位点，并通过例如脂质环境的变化来感知Arf何时应该失活。持续的研究旨在确定Arf和Arf GAP之间以及Arf和GGA之间的相互作用位点。此外，我们正在研究Arf GAP - Arf相互作用在膜运输事件（如蛋白分泌和胞吐）期间发生的货物分选中的潜在作用。 实验室的第二个重点是检查ASAP家族成员的特定细胞作用。我们首先考察了每个亚科的代表性成员。已经发现ASAP 1定位于并控制粘着斑的转换，粘着斑是将细胞锚于基质的结构，并且粘着斑必须被重塑以使细胞运动发生。已经发现ACAP 1调节Arf 6依赖的富含肌动蛋白的突起形成，这一事件被认为与细胞的伸展和运动有关。ARAP 1也被发现调节膜运输和肌动蛋白细胞骨架，作为调节细胞运动的信号网络中的节点发挥作用。PIP 3与ARAP 1结合，激活Arf GAP，从而使Arf失活并控制高尔基体功能。此外，ARAP 1还可诱导Cdc 42的激活和Rho的失活。已经发现这两种蛋白质的相互调节诱导细胞迁移。因此，一般来说，ASAP家族的Arf GAP似乎调节细胞迁移中涉及的事件。持续的研究旨在（i）进一步描述Arf GAP在信号传导中的作用，（ii）识别依赖于Arf GAP信号传导的特定生物学事件，例如：免疫细胞的发育和功能，以及（iii）评估可能参与病理过程，特别是肿瘤细胞侵袭和转移。 Z 01 BC 07365-03 LBC至LCO