ROLE OF N-GLYCOSYLATION IN E-CADHERIN MEDIATED CELL-CELL ADHESION

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。 E-钙粘蛋白是一种分子量为120-kDa的膜糖蛋白，在上皮细胞中表达，是细胞间建立粘附连接的主要参与者。粘附连接具有细胞内和细胞外锚定点以调节细胞-细胞相互作用。[1-2]粘附连接的组装或拆卸的改变与细胞状态的主要变化相关，包括分化和增殖[3]以及癌症进展。在许多类型的癌症中，E-钙粘蛋白功能的丧失是常见的事件，通常由E-钙粘蛋白表达减少或异常引起。[4]美国联邦储备委员会 最近的研究表明，N-糖基化模式的E-钙粘蛋白的粘附连接的分子组织中的作用。具体而言，复合N-聚糖的存在与不稳定的粘附连接相关。[5]对E-钙粘蛋白的结构特征，特别是其N-糖基化模式和蛋白结合伴侣的研究，为E-钙粘蛋白介导的粘附和细胞信号传导功能提供了深入了解。 分离这种大的膜蛋白需要开发特定的方法。 我们的方法已经分离出了具有不同结合伴侣和不同N-糖基化状态的E-钙粘蛋白的池，这取决于细胞状态。 恶性细胞中的E-钙粘蛋白的形式比非恶性细胞中的形式更高度糖基化;它们以更高的表观重量迁移，如通过Western印迹和切下的SDS-PAGE条带的肽质量指纹图谱检测到的。 通过持续的研究来鉴定蛋白质组分，我们发现E-钙粘蛋白与恶性细胞中的不稳定蛋白质相关联的程度比它存在于非恶性细胞中的程度更大。 还研究了E-钙粘蛋白N-糖基化，特别是位点占用和N-聚糖组成。凝胶内酶促释放的N-聚糖的MALDI-TOF MS分析表明E-钙粘蛋白主要含有复合N-聚糖。 这项工作强调了细胞环境，特定蛋白质的粘附复合物的募集，沿着特定的结构修饰，E-钙粘蛋白可以定义E-钙粘蛋白介导的粘附的整体稳定性。 参考文献： 1. Gottardi CJ，Wong E，Gumbiner BM.细胞生物学杂志2001; 153（5）：1049-60 2. 放大图片作者：Perez-Moreno M，Jamora C，Fuchs E. Cell 2003; 112（4）：535-48 3. 甘比纳Nat Rev Mol Cell Biol 2005; 6：622-634 4. 惠洛克MJ，约翰逊KR. Annu Rev Cell Dev Biol 2003; 19：207-35 5. Liwosz A，Lei T和Kukuruzinska MA. J Biol Chem 2006; 281：23138-49.

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. E-cadherin is a 120-kDa membrane glycoprotein, expressed in epithelial cells, which is the main player in establishing adherens junctions between cells. The adherens junctions have both intra and extracellular anchorage points in order to regulate cell-cell interactions.[1-2] Alterations in the assembly or disassembly of adherens junctions occur in association with major changes in the state of cell, including differentiation and proliferation [3], as well as in cancer progression. Loss of E-cadherin function is a frequent event in many types of cancer, commonly caused by diminished or aberrant E-cadherin expression. [4] Recent studies have indicated that the N-glycosylation pattern of E-cadherin has a role in the molecular organization of adherens junctions. Specifically, the presence of complex N-glycans is associated with destabilized adherens junctions. [5] Investigation into the structural characteristics of E-cadherin, specifically its N-glycosylation pattern and protein binding partners, provide insight into E-cadherin mediated adhesion and cell signaling functions. Isolation of this large membrane protein has required the development of specific methods. Our methodology has isolated pools of E-cadherin with different binding partners and different N-glycosylation states, depending on cell status. The forms of E-cadherin in malignant cells are more highly glycosylated than are those in non-malignant cells; they migrate at a higher apparent weight, as detected by Western blot and peptide mass fingerprinting of excised SDS-PAGE bands. Through continued studies to identify the protein components, we have found that E-cadherin is associated with destabilizing proteins in malignant cells to a greater extent than when it is present in non-malignant cells. E-cadherin N-glycosylation has also been investigated, specifically site occupancy and N-glycan composition. MALDI-TOF MS analysis of in-gel enzymatically released N-glycans suggests E-cadherin contains predominantly complex N-glycans. This work highlights that cell context, the recruitment of specific proteins to the adhesion complex, along with specific structural modifications to E-cadherin may define the overall stability of E-cadherin mediated adhesion. References: 1. Gottardi CJ, Wong E, Gumbiner BM. J Cell Biol 2001; 153(5): 1049-60 2. Perez-Moreno M, Jamora C, Fuchs E. Cell 2003; 112(4): 535-48 3. Gumbiner BM. Nat Rev Mol Cell Biol 2005; 6:622-634 4. Wheelock MJ, Johnson KR. Annu Rev Cell Dev Biol 2003; 19:207-35 5. Liwosz A, Lei T, and Kukuruzinska MA. J Biol Chem 2006; 281:23138-49.