Functional analysis of ER and Golgi subdomains

ER 和高尔基体亚域的功能分析

• 批准号: BB/K007181/1
• 负责人: Jurgen Denecke
• 金额: $ 48.69万
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FK007181%2F1
• 关键词: Functional; analysis; ER; Golgi; subdomains

Understanding how proteins are sorted to the right place in a living cell is comparable to the task of the Royal Mail to first sort letters and packages by destination and secondly to deliver them correctly at minimal cost and in a reasonable timeframe. The Golgi apparatus is a sorting station of the secretory pathway from which proteins can be sorted in at least three directions, to the cell surface (secreted proteins), to the vacuole or the endoplasmic reticulum (ER). The ER can be compared to the manufacturing site for a range of products that will be shipped first to the Golgi for subsequent sorting and delivery. To stay in business, manufacturing sites require efficient transport routes to distribution centres. This also means that vehicles should not travel when they are not properly loaded, and they should be doing something useful when they return, such as bringing some mail back. This is not an easy task, and the same is true for the sorting of proteins in living cells. However, cells are very efficient at organising cost-effective supply chains and have developed very efficient transport processes in which no step is perfect but little is left to chance due to efficient back-up mechanisms. This includes the recycling of essential machinery so that they can be engaged in multiple transport reactions during their life-span.Numerous protein sorting signals (address labels) have been described in the last 20 years and in many cases receptor molecules (lorry drivers) have been identified that bind to the sorting signals and package them into transport vesicles (the lorries). It is however much less clear how the sorting receptors know how to find their way in the cell. In other words how exactly do the lorry drivers reach their right destination, who gives them their instructions and who sends them back for new jobs when they have delivered their cargo? In the cell, sorting receptors must not only bind to ligands in one compartment, they must also transport them to another compartment, release them there, and return back to the original compartment to select new proteins again.We would now like to use our recent discoveries to shed light on the complete process of ER retention in plants. Many proteins exported from the ER are meant to be returned, just like the wooden pallets are not discarded in modern logistic firms but they are in fact recycled so that they can be used again to be packed with new cargo. One problem is that there are many more proteins to be recycled than receptors available. Receptors have to bind their cargo very efficiently in the Golgi and preferentially release them in the ER in a place where they will stay for a longer time, whilst the receptors move back to the Golgi using a frequent flyer ticket. This is why we find it exciting that ER import sites and ER export sites are physically separated from each other and we can now start to explore how this is achieved. We have also discovered that plants contain two types of Golgi bodies. This is very exciting, because it suggests that instead of one basic distribution centre the plant uses at least two. It was always believed that the Golgi apparatus is a single organelle, so our finding is of major importance. The new Golgi type can be seen with fluorescently tagged receptors (lorry drivers) which represent a new class found in plants, algae and some unicellular organisms but is absent in animals and yeasts. We must first learn how this new class of receptors reaches the new class of Golgi bodies, and next we would like to see what happens if we eliminate this class of receptors and see why plants use these receptors.Finally, we need to identify more proteins residing in the new compartments that we have discovered to gain a better understanding of protein sorting to the plant vacuoles, which host the vast majority of edible protein on earth. Plant proteins constitute a major food source and must be harnessed as well as we can.

了解蛋白质如何在活细胞中被分类到正确的位置，就像皇家邮政的任务一样，首先按照目的地对信件和包裹进行分类，其次以最低的成本在合理的时间内正确地交付它们。高尔基体是分泌途径的分选站，蛋白质可以从高尔基体在至少三个方向上被分选到细胞表面（分泌的蛋白质）、到液泡或内质网（ER）。ER可以与一系列产品的生产现场进行比较，这些产品将首先被运送到高尔基体进行随后的分拣和交付。为了维持业务，制造地点需要通往分销中心的高效运输路线。这也意味着车辆不应该在没有适当装载的情况下行驶，并且在返回时应该做一些有用的事情，例如带回一些邮件。这不是一件容易的事，活细胞中蛋白质的分选也是如此。然而，电池在组织具有成本效益的供应链方面非常有效，并且开发了非常有效的运输过程，其中没有一个步骤是完美的，但由于有效的备份机制，几乎没有机会。在过去的20年里，许多蛋白质分选信号（地址标签）被描述出来，在许多情况下，受体分子（卡车司机）被识别出来，它们与分选信号结合，并将它们包装成运输囊泡（卡车）。然而，目前还不太清楚分选受体如何知道如何在细胞中找到它们的方式。换句话说，卡车司机到底是如何到达正确的目的地的，谁给他们指示，谁在他们交付货物后把他们送回新的工作岗位？在细胞中，分选受体不仅必须与一个区室中的配体结合，还必须将它们运送到另一个区室，在那里释放它们，然后返回到原始区室再次选择新的蛋白质。从ER出口的许多蛋白质都是要返回的，就像现代物流公司不会丢弃的木托盘一样，但它们实际上是回收的，以便它们可以再次用于包装新的货物。一个问题是，需要回收的蛋白质比可用的受体多得多。受体必须在高尔基体中非常有效地结合它们的货物，并优先在ER中释放它们，在那里它们将停留更长时间，而受体则使用常旅客票回到高尔基体。这就是为什么我们发现ER导入站点和ER导出站点在物理上彼此分离是令人兴奋的，我们现在可以开始探索如何实现这一点。我们还发现植物含有两种类型的高尔基体。这是非常令人兴奋的，因为它表明，而不是一个基本的分销中心，工厂使用至少两个。人们一直认为高尔基体是一个单一的细胞器，因此我们的发现非常重要。新的高尔基体类型可以用荧光标记的受体（卡车司机）看到，这代表了在植物，藻类和一些单细胞生物中发现的新类别，但在动物和酵母中不存在。我们必须首先了解这类新的受体是如何到达新的高尔基体的，接下来我们想看看如果我们消除这类受体会发生什么，以及为什么植物会使用这些受体。最后，我们需要鉴定更多的蛋白质居住在我们发现的新隔室中，以更好地了解蛋白质分选到植物液泡中，地球上绝大多数的可食用蛋白质都在那里。植物蛋白是一种主要的食物来源，我们必须尽可能地加以利用。

项目成果

Subcellular localization and trafficking of phytolongins (non-SNARE longins) in the plant secretory pathway.

• DOI: 10.1093/jxb/erw094
• 发表时间: 2016-04
• 期刊: Journal of experimental botany
• 影响因子: 6.9
• 作者: de Marcos Lousa C;Soubeyrand E;Bolognese P;Wattelet-Boyer V;Bouyssou G;Marais C;Boutté Y;Filippini F;Moreau P
• 通讯作者: Moreau P

Lysosomal and vacuolar sorting: not so different after all!

溶酶体和液泡分类：毕竟没有那么不同！

• DOI: 10.1042/bst20160050
• 发表时间: 2016-06-15
• 期刊: Biochemical Society transactions
• 影响因子: 3.9
• 作者: de Marcos Lousa C;Denecke J
• 通讯作者: Denecke J