Structural Biology of Cell Surface Mucin Domains

细胞表面粘蛋白结构域的结构生物学

• 批准号: 6725902
• 负责人: DAVID H LIVE
• 金额: $ 23.8万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-30 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6725902
• 关键词: CD antigens; CD43 molecule; animal tissue; biological signal transduction; conformation; glycoprotein biosynthesis; membrane proteins; molecular shape; mucins; nuclear magnetic resonance spectroscopy; protein isoforms; protein protein interaction; protein structure function; structural biology

DESCRIPTION (provided by applicant): Mucin glycoprotein domains are important components of the cell surface landscape prevalent on various cell types including those of the immune system. These are characterized by a high level of O-glycosyalted serine and threonine in their sequences. Two proteins with such mucin domains, CD43 and CD45, comprise about 30% of the surface of T-cells. Such domains are significant in cell-cell interactions and recognition, and molecular localization related to these events have consequences for the signal transduction events mediated by their intracellular domains. Both carbohydrate and polypeptide components of the glycoproteins contribute to molecular recognition, with O-glycosylation having a profound conformational effect, inducing an extended arrangement of the protein backbone. The significance of the carbohydrate epitopes on these glycoproteins is born out by their specific variation with the state of the cell, stage of development and disease, offering an additional dimension to the diversity for cellular signaling and a target for cell specific therapeutic intervention. The extended structure of CD43 makes it one of the first cellular components encountered by the outside environment. Since molecular recognition is central to the roles of these giycoproteins, the proposed research will investigate their structure, required to understand function and interactions. These molecules have resisted detailed structural analysis in large part because of difficulties in isolating suitable homogeneous material from natural sources. Initially, our studies have demonstrated that chemical synthesis and nuclear magnetic resonance spectroscopy techniques can be joined to obtain a high resolution description of a mucin motif from CD43. Our aims are to extend this, first, to determine structures of other representative motifs and further elucidate the principles controlling molecular organization, second, to use this in characterizing larger segments of mucins, and third to relate this to their recognition by other molecules such as antibodies and galectin. Interactions of CD43 and CD45 with galectin-1 causes their segregation into separate patches and ultimately T-cell programmed cell death. Our studies will examine this interaction, providing insight into this process and into possible control of autoimmune disease. On tumor cells, these glycoproteins are characterized by their aberrant glycosylation, and a structural understanding could aid in further development of glycopeptide anti-tumor vaccines.

描述（由申请人提供）： 粘蛋白糖蛋白结构域是在包括免疫系统的各种细胞类型上普遍存在细胞表面景观的重要组成部分。这些特征在于，其序列中高水平的O-糖符号丝氨酸和苏氨酸。两种具有这种粘蛋白结构域CD43和CD45的蛋白质​​，约占T细胞表面的30％。这种结构域在细胞 - 细胞相互作用和识别中很重要，与这些事件相关的分子定位对由其细胞内结构域介导的信号转导事件产生了影响。糖蛋白的碳水化合物和多肽成分均有助于分子识别，O-糖基化具有深远的构象作用，从而诱导了蛋白质主链的扩展排列。碳水化合物表位对这些糖蛋白的重要性是由于它们与细胞状态，发育和疾病阶段的特异性变化所产生的，为细胞信号传导的多样性提供了额外的维度，以及针对细胞特异性治疗干预的靶标。 CD43的扩展结构使其成为外部环境遇到的第一个蜂窝组件之一。由于分子识别是这些姜黄蛋白的作用的核心，因此拟议的研究将研究其结构，需要了解功能和相互作用。这些分子在很大程度上抗拒了详细的结构分析，这在很大程度上是因为困难将合适的均匀材料与自然来源隔离开来。最初，我们的研究表明，可以连接化学合成和核磁共振光谱技术，以获得CD43的粘蛋白基序的高分辨率描述。我们的目的是首先扩展这一点，以确定其他代表性基序的结构，并进一步阐明控制分子组织的原理，其次，将其用于表征较大的粘蛋白片段，第三种将其与其他分子（例如抗体和甘肠蛋白）识别。 CD43和CD45与Galectin-1的相互作用导致其分离成单独的斑块，并最终导致T细胞编程的细胞死亡。我们的研究将研究这种相互作用，从而洞悉此过程并可能控制自身免疫性疾病。在肿瘤细胞上，这些糖蛋白的特征是它们的异常糖基化，结构理解可以有助于进一步发展糖肽抗肿瘤疫苗。