Elucidating the pathways and machinery of constitutive secretion

人体由数十亿个细胞组成，每个细胞又被进一步组织成一系列的隔间。细胞在某些方面类似于微型城市，这些隔室就像制造特定产品的工厂，例如内质网参与制造蛋白质和脂质。一旦蛋白质或脂质被制造出来，它的功能通常在细胞内的其他地方被需要。为了将这些蛋白质和脂质运送到需要它们的地方，小包装（囊泡）从一个隔室分离并与另一个隔室融合，从而运送它们的内容物。这些小泡就像卡车一样，将货物运送到城市的不同目的地。在某些情况下，细胞外需要新生成的蛋白质，因此携带这些蛋白质的囊泡与覆盖细胞表面的膜（质膜）融合。这个过程被称为组成性分泌，是许多重要过程如炎症和免疫系统功能所必需的。分泌物的变化可引起疾病，而且越来越多的罕见遗传疾病是由分泌所需蛋白质的突变引起的。我的实验室对鉴定和表征生成、运输和融合分泌囊泡与质膜所需的蛋白质感兴趣。为了确定这种机制，我们开发了测量分泌的新方法，并将它们与允许破坏单个基因功能的技术结合起来。使用这种方法，我们已经确定了两种蛋白质，STX19和SNAP29，它们是分泌所必需的。该提案旨在表征这些蛋白质的功能，特别是我们有兴趣了解SNAP29和STX19是如何被调节的，以及这些蛋白质如何靶向到细胞内的正确位置。我们还对确定SNAP29和STX19是否参与细胞中所有类型蛋白质的分泌或仅参与特定子集感兴趣。这项工作将使社会受益，因为它将增加我们对基本细胞过程的理解，并在未来可能有助于开发新的诊断或治疗方法，以治疗由分泌缺陷引起的疾病。特别是，我们的工作应该有助于理解由SNAP29缺失引起的罕见致命疾病CEDNIK（大脑发育不良、神经病变、鱼鳞病和角化病）综合征的病理。

The human body is made up from billions of cells and each of these cells is further organised into a series of compartments. Cells in some ways resemble miniature cities and these compartments are just like factories that make specific products, for example the endoplasmic reticulum is involved in making proteins and lipids. Once a protein or lipid has been made, its function is often required somewhere else within the cell. To transport these proteins and lipids to the site where they are needed, small packages (vesicles) break off from one compartment and fuse with another, thereby delivering their contents. These vesicles are just like lorries taking goods to different destinations within the city. In some cases the newly made proteins are required outside the cell so the vesicles carrying these proteins fuse with the membrane that covers the cell surface (plasma membrane). This process is called constitutive secretion and is required for many important processes such as inflammation and immune system function. Changes in secretion can cause disease and there is an increasing number of rare genetic disorders cause by mutations in proteins required for secretion. My laboratory is interested in identifying and characterising proteins required for generating, transporting and fusing secretory vesicles with the plasma membrane. To identify this machinery we have developed new ways of measuring secretion and used them with technologies that allow the function of individual genes to be disrupted. Using this approach we have identified two proteins, STX19 and SNAP29, that are required for secretion. This proposal aims to characterise the function of these proteins, in particular we are interested in understanding how SNAP29 and STX19 are regulated and how these proteins are targeted to the correct place within the cell. We are also interested in determining whether SNAP29 and STX19 are involved in the secretion of all types of proteins from cells or just a specific subset.This work will benefit society because it will increase our understanding of a fundamental cellular process and in the future may help in the development of new diagnostics or therapeutics for the treatment of diseases caused by defective secretion. In particular, our work should help in understanding the pathologies which occur in the rare fatal disease CEDNIK (CErebral Dysgenesis, Neuropathy, Ichthyosis, and Keratoderma) syndrome which is caused by the loss of SNAP29.