Characterization of Clathrin-Coated Vesicles

已经证明，豌豆发育过程中的子叶提供了丰富的胞壁蛋白包衣小泡(CCV)来源。看来，与哺乳动物CCV相似，植物CCV由一个由重链和轻链、接头和膜泡组成的笼子组成，其中包含与货物蛋白络合的受体。从子叶中分离的CCV主要是跨高尔基体起源的，它们的接头可能不同于特征较好的哺乳动物CCV，后者主要来自质膜起源。计划对初步发现的结果进行扩展，这些发现显示了与植物CCV不同的接头部分的肽组成。已鉴定出一种与空泡蛋白N端靶向肽相互作用的潜在受体蛋白。将对该受体进行鉴定，并研究其在选择蛋白体蛋白中的作用，以及它与CCV组分的相互作用。积累的信息将为理解植物中蛋白质的囊泡运输提供关键信息，并将为扩大与动物和其他系统的比较研究提供基础。%所有真核细胞的一个关键特征是它们在物理上是分开的。也就是说，细胞质不是细胞成分的统一混合物，而是以这样一种方式高度组织起来的，即特定的功能和执行这些功能的组件定位于细胞的离散区域，甚至位于细胞外部(例如，分泌材料、细胞壁等)。这些在功能上不同的隔室中的一些由膜来限定。因此，必须有机制来确保特定的蛋白质到达它们特定的亚细胞位置。包被的囊泡系统是这种机制的一部分。包被囊泡是包含蛋白质的穿梭囊泡或转运体。在哺乳动物系统中，包被的囊泡在内吞作用(将外部蛋白质输送到细胞内)和新合成的蛋白质从高尔基体到溶酶体前或分泌前隔室的细胞内移动中的作用已经得到了很好的研究。在植物中，人们对涂层囊泡的功能或结构知之甚少，一些现有的信息在该领域是有争议的主题。被包被的囊泡很可能在将特定蛋白质运输到液泡、种子储存体和生长的细胞壁中发挥重要作用。因此，详细了解它们的结构和功能将是农业生物技术的关键。这个项目承诺提供关于一个非常重要的植物生物学主题的可靠的信息。

It has been demonstrated that cotyledons from developing peas provide a rich source of clathrin coated vesicles (ccvs). It appears that, in similarity to mammalian ccvs, those from plants are composed of a clathrin cage consisting of heavy and light chains, adaptors, and a membrane vesicle component containing receptors to which cargo proteins are complexed. The ccvs isolated from cotyledons are primarily of trans-Golgi origin, and their adaptors are expected to differ from those of the better characterized mammalian ccvs which are principally of plasma membrane origin. It is planned to extend on the preliminary findings which have shown a different peptide composition of the adaptor fraction from plant ccvs. A potential receptor protein which interacts with the N-terminal targeting peptide of vacuolar proteins has been identified. This receptor will be characterized and its role in selecting protein body proteins, along with its interaction with ccv components, will be investigated. The information accumulated will provide crucial information to the understanding of vesicular transport of proteins in plants and will provide a basis for extended comparative studies with animal and other systems. %%% A key feature of all eukaryotic cells is that they are physically compartmentalized. That is, cytoplasm is not a uniform mixture of cellular components, but rather it is highly organized in such a way that specific functions, and the components that carry out those functions, are localized in discrete regions of the cell, or even external to the cell (e.g., secreted materials, cell walls, etc.). Some of these functionally distinct compartments are bounded by membranes. It follows that there must be mechanisms to ensure that specific proteins get to their particular subcellular locations. The coated vesicle system is part of this mechanism. Coated vesicles are shuttle vesicles, or transporters, of proteins contained within them. In mammalian systems, the role of coated vesicles in endocytosis (the transport of external proteins into the cell) and in intracellular movement of newly synthesized proteins from the Golgi apparatus to pre-lysosomal or pre-secretory compartments is well-studied. In plants, relatively little is known about coated vesicle function or structure, and some of the available information is the subject of controversy in the field. Coated vesicles are very likely to play significant roles in the transport of specific proteins to the vacuole, to seed storage bodies, and to the growing cell wall. As such, a detailed understanding of their structure and function will be critical to agricultural biotechnology. This project promises to yield solid, reliable information about a very important plant biology subject.