Mechanism and function of a novel actin nucleator

新型肌动蛋白成核剂的机制和功能

• 批准号: 7085980
• 负责人: R DYCHE MULLINS
• 金额: $ 25.52万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7085980
• 关键词: Drosophilidae; actins; arthropod genetics; biochemical evolution; cell nucleus; cytoskeletal proteins; egg /ovum; intermolecular interaction; molecular assembly /self assembly; molecular polarity; mutant; protein protein interaction; protein structure; protein structure function

DESCRIPTION (provided by applicant): We recently showed that the product of the Drosophila spire gene, p150-Spir (Spir) nucleates actin filament formation by a unique mechanism (Quinlan et al., 2005). We recently discovered that Spir binds directly to members of another class of actin nucleators, the Cappuccino-family formins (Preliminary Results). This result is consistent with previous genetic studies indicating that the two proteins operate in the same pathway to specify both anterior-posterior and dorsal-ventral axes of developing embryos (Manseau and Schupach, 1989) and localization studies demonstrating that they have identical expression patterns in embryonic and adult mammalian tissues (Schumacher et al., 2004). Spir- and Cappuccino-family proteins are conserved across metazoan species from fruitflies to humans and in mammals and every organism known to express a Spir-family protein also expresses a Cappuccino-family formin. Despite their conservation and their importance in development, however, the function and regulation of Spir and Capu are not well understood. Our results suggest that the activities of Spir and Cappuccino are directly coupled and that they may function together in vivo as a single filament-forming complex. Our long-term goal is to understand how these actin nucleation factors work together to determine polarity of oocytes and embryos. Our short-term goals are to understand the activities of Spir and Capu alone and in complex. We will also investigate a potential mechanism by which the two proteins may be targeted in vivo. Specifically, we will: 1. Determine the mechanism of actin nucleation by Spir. 2. Characterize the interaction of Cappuccino with actin. 3. Characterize the interaction between Spir and Cappuccino. 4. Characterize the interaction of the Spir FYVE domain with lipids.

描述（由申请人提供）：我们最近表明，果蝇 spire 基因的产物 p150-Spir (Spir) 通过独特的机制使肌动蛋白丝形成成核 (Quinlan 等，2005)。我们最近发现 Spir 直接与另一类肌动蛋白成核剂——卡布奇诺家族福明斯的成员结合（初步结果）。这一结果与之前的遗传研究一致，表明这两种蛋白以相同的途径起作用，以指定发育胚胎的前后轴和背腹轴（Manseau和Schupach，1989），并且定位研究表明它们在胚胎和成年哺乳动物组织中具有相同的表达模式（Schumacher等，2004）。 Spir 和 Cappuccino 家族蛋白在从果蝇到人类和哺乳动物的后生动物物种中都是保守的，并且已知表达 Spir 家族蛋白的每种生物体也表达 Cappuccino 家族福尔马林。然而，尽管 Spir 和 Capu 的保护及其在发展中的重要性，但人们对 Spir 和 Capu 的功能和调节仍知之甚少。我们的结果表明，Spir 和 Cappuccino 的活性是直接耦合的，并且它们可能在体内作为单个丝形成复合物一起发挥作用。我们的长期目标是了解这些肌动蛋白成核因子如何共同作用来确定卵母细胞和胚胎的极性。我们的短期目标是了解 Spir 和 Capu 的单独活动和复杂活动。我们还将研究这两种蛋白质在体内靶向的潜在机制。具体来说，我们将： 1. 通过Spir确定肌动蛋白成核机制。 2. 表征卡布奇诺与肌动蛋白的相互作用。 3. 描述 Spir 和 Cappuccino 之间的相互作用。 4. 表征 Spir FYVE 结构域与脂质的相互作用。