Molecular Regulation of Exocytosis

描述（申请人提供）：胞吐是由分泌囊泡从反式高尔基网络和核内体向质膜的运输、对接和融合介导的。由于胞吐在从激素释放到胚胎发生的广泛生理过程中起着中心作用并受到严格控制，因此了解胞吐调节的分子机制非常重要。我们的研究重点是胞吐途径中两个独立但相互联系的“模块”，即Rab GTPases和胞吐复合物，这两个模块从酵母到人类都是进化保守的。在本研究中，我们将首先研究Rabin8激活的分子机制，Rabin8是Rab8的鸟嘌呤核苷酸交换因子（GEF）， Rab8是哺乳动物细胞胞外分泌的主要调节因子。我们将研究磷脂酰亚苷和上游rabb蛋白Rab11在Rabin8激活中的作用。此外，我们将研究细胞外信号调节激酶1/2 （ERK1/2）在响应表皮生长因子（EGF）信号传导过程中对Rabin8 GEF活性的磷酸化和调控。最后，我们将确定胞囊在snare介导的膜融合中的作用。我们采用多学科方法结合生物化学，生物物理学，酵母遗传学和显微成像来解决该领域的关键问题。这些研究不仅有助于我们在分子水平上阐明胞吐的调控机制，而且有助于我们对糖尿病、多囊肾病（PKD）等多种疾病的认识。

DESCRIPTION (provided by applicant): Exocytosis is mediated by transport, docking and fusion of secretory vesicles from trans-Golgi network and endosomes to the plasma membrane. As exocytosis is centrally involved, and tightly controlled, in a wide range of physiological processes from hormone release to embryogenesis, it is important to understand the molecular mechanisms that regulate exocytosis. Our research focuses on two separate but connected "modules" in the exocytosis pathway, the Rab GTPases and the exocyst complex, both of which are evolutionarily conserved from yeast to humans. In this proposal, we wil first investigate the molecular mechanisms that control the activation of Rabin8, which is the guanine nucleotide exchange factor (GEF) for Rab8, a major regulator of exocytosis in mammalian cells. We will examine the role of phosphatidylinositides and an upstream Rab protein, Rab11, in the activation of Rabin8. In addition, we will examine the phosphorylation and regulation of Rabin8 GEF activity by Extracellular signal-regulated kinases 1/2 (ERK1/2) in response epidermal growth factor (EGF) signaling. Finally, we will determine the role of the exocyst in SNARE-mediated membrane fusion. We take a multi-disciplinary approach combining biochemistry, biophysics, yeast genetics and microscopic imaging to address key questions in the field. These studies will not only help us elucidate the regulatry mechanisms of exocytosis at the molecular level, but also contribute to our understanding of a number of diseases such as diabetes and polycystic kidney diseases (PKD).