Understanding the Biology of Chronic Ulcers: Histological and Molecular Basis...

经典钙粘蛋白的细胞粘附的分子机制现在在原子水平上被理解， 详细然而，桥粒钙粘蛋白功能的基础尚未确定。飞行员和 可行性项目的重点是确定第一个高分辨率结构的桥粒钙粘蛋白， 以确定其细胞粘附功能的详细分子基础。钙粘蛋白家族是 其特征在于它们的细胞外钙粘蛋白重复结构域（EC 1-EC 5）。已知粘合剂 钙粘蛋白胞外区的功能依赖于钙离子在细胞外基质中的结合， 这些重复域导致整个区域的硬化，然而， 和引起粘附的相互作用还没有清楚地了解。在这个问题上， 最近，当我们的小组解决了C-cadherin胞外结构域的晶体结构时。这 结构显示，当细胞表面的C-钙粘蛋白与细胞表面的C-钙粘蛋白结合时， 一个细胞上的C-钙粘蛋白的保守色氨酸（Trp 2）残基嵌入疏水口袋， 含有高度保守的R-A-L残基的C-钙粘蛋白。此外，据指出， 同一细胞表面上的C-cadherins可能通过类似的机制相互作用，促进分子聚集 从而允许增强细胞之间的粘附。Trp 2残基和疏水结合 口袋是保守的桥粒钙粘蛋白，因此，它似乎可能是桥粒糖蛋白和 桥粒柯林斯可以通过相同的机制相互作用。然而，迄今为止，没有晶体结构的任何 桥粒钙粘蛋白已被解决。这让我们产生了一个假设：粘合剂的结构是什么 桥粒钙粘蛋白的界面桥粒钙粘蛋白的粘附界面是如何相互作用， 有助于桥粒的形成为了获得一些了解的结构， 桥粒钙粘蛋白的胞外结构域，我们已经开始与安吉拉博士合作， Christiano博士在哥伦比亚大学皮肤病学系的研究中， 人桥粒芯糖蛋白。本试点和可行性研究的目标是了解详细的分子 钙粘蛋白在桥粒细胞间连接中的作用机制。 博士Shapiro符合指南中资格类别#2的资格，作为既定研究者， 以前的研究工作与SDRC有关。他是国际知名的结构生物学家， 已经解析了许多经典钙粘蛋白的结构在这一建议中，他将把注意力转向 桥粒钙粘蛋白，皮肤生物学的核心角色。Shapiro博士的P&F研究利用了核心C和D。

The molecular mechanism of cell adhesion by classical cadherins is now understood at an atomic level of detail. However, the basis of desmosomal cadherin function has not yet been determined. This Pilot and Feasibility project is focused on determining the first high-resolution structures of desmosomal cadherins in order to determine the detailed molecular.basis of their cell adhesive function. The cadherin family is characterized by their extracellular cadherin repeat domains (EC1-EC5). It is known that the adhesive function of the cadherin extracellular region is dependent upon the binding of calcium ions between each of these repeat domains which leads to the rigidification of the entire region, however, the specific interfaces and interactions responsible for adhesion are not clearly understood. Some light was shed on this issue recently when the crystal structure of the extracellular domain of C-cadherin was solved by our group. This structure revealed that binding between C-cadherins on opposing cell surfaces most likely occurs when a conserved tryptophan (Trp2) residue of a C-cadherin on one cell intercalates into a hydrophobic pocket, containing highly conserved R-A-L residues, of a C-cadherin on an opposing cell. Further, it was noted that C-cadherins on the same cell surface may interact via a similar mechanism to promote molecular clustering thereby allowing for enhanced adhesion between cells. Both the Trp2 residue and the hydrophobic binding pocket are conserved in desmosomal cadherins, therefore, it seems likely that desmogleins and desmocollins may interact via this same mechanism. However, to date no crystal structure for any of the desmosomal cadherins has been solved. This led us to hypothesize: What is the structure of the adhesive interface of a desmosomal cadherin? How do the adhesive interfaces of desmosomal cadherins interact to contribute to the formation of desmosomes? In order to gain some understanding about the structure of the extracellular domain of desmosomal cadherins, we have embarked on a collaborative effort with Dr. Angela Christiano in the Department of Dermatology at Columbia University to crystallize the extracellular domain of human desmogleins. The goal of this Pilot and Feasibility study is to understand the detailed molecular mechanisms of cadherin function in desmosome intercellular junctions. Dr. Shapiro qualifies under eligibility Category #2 in the Guidelines as an Established Investigator with no previous work in research related to the SDRC. He is an internationally renowned structural biologist who has resolved the structure of many classical cadherins. In this proposal, he will turn his attention to the desmosomal cadherins, central players in skin biology. Dr. Shapiro's P&F study utilizes Cores C and D.