STRUCTURAL ANALYSIS OF SPRINTER

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 最近，我们在果蝇中鉴定了一种新的多跨膜蛋白，我们将其命名为Sprinter（Srt），其是从配体表达细胞分泌活性Wg/Wnt所必需的。尽管已知Srt对于活性Wg/Wnt的分泌是必需的，但其在Wnt的复杂成熟过程中的实际功能尚不清楚。Srt氨基酸的分析表明它可能有几种可能的拓扑结构。我们假设Srt具有4个跨膜结构域，其中N端有一个大的球状细胞外/管腔结构域，这可能构成该蛋白的主要功能区域。该区域包括未知功能的保守结构域DUFF 1141。本提案的总体目标是启动Srt球状细胞外/管腔结构域的结构和功能表征，并确定Srt的总体拓扑结构。为此，我们将首先进行拓扑研究，以确认我们预测的结构。接下来，我们将开发允许高水平表达N-末端Srt的构建体，用于其纯化以及其体内表达。我们将使用这些工具，以确定在体内的N-末端区域的功能，并确定是否Srt和它的N-末端区域与Wg/Wnt和可能参与Wnt加工的其他蛋白质相互作用。最终，我们相信这些研究将导致与特拉华州大学的实验室合作，通过X射线晶体学或核磁共振对纯化的Srt N-末端球状结构域进行结构分析，以整合Srt的结构和功能方面。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Recently, we have identified a novel multi-transmembrane protein in Drosophila we named Sprinter (Srt), which is required for the secretion of active Wg/Wnt from ligand expressing cells. Although it is known that Srt is necessary for secretion of active Wg/Wnt, its actual function in the complex maturation process of Wnts is not yet understood. Analysis of the Srt amino acid suggests it could have several possible topologies. We hypothesize Srt has 4 transmembrane domains with a large N-terminal globular extracellular/luminal domain which likely constitutes the predominate functional region of this protein. This region includes a conserved structural domain of unknown function, DUFF1141. The overall objective of this proposal is to initiate structural and functional characterization of the Srt globular extracellular/luminal domain and determine the overall topology of Srt. To do this we will first perform topological studies to confirm our predicted structure. Next, we will develop constructs that will allow for high levels of expression of N-terminal Srt for its purification, as well as its in vivo expression. We will use these tools in order to ascertain the function of the N-terminal region in vivo and determine if Srt and its N-terminal region interact with Wg/Wnt and possibly other proteins involved in Wnt processing. Ultimately we believe these studies will lead to collaboration with a laboratory here at the University of Delaware to perform structural analysis of the purified Srt N-terminal globular domain by X-ray crystallography or nuclear magnetic resonance to the integrate structural and functional aspects of Srt.