ANALYSIS OF TYROSINE SULFATION: HIV

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。 这项合作是对酪氨酸硫酸化的广泛研究， 蛋白质和肽激素的广泛翻译后修饰 通过动物细胞的高尔基体系统。 当项目开始时， 仅限于一些参与消化系统的肽激素， 过程和一些，例如胆囊收缩素（CCK），活性都在 胃肠道和中枢神经系统。 两种组织 表达不同但密切相关的受体。 酪氨酸硫酸化 据估计，翻译后修饰发生在大约百分之一的 大鼠蛋白质中的酪氨酸残基。 我们最初的论文集中在寻找 以及可以用来准确预测酪氨酸硫酸化的测试规则 站点（1，2，3）。 这些初步研究得出的结论是， 酪氨酰蛋白磺基转移酶，催化硫酸化的酶， 蛋白质和肽中的酪氨酸残基，具有相对低的底物 特异性，并可能修饰任何酪氨酸残基， 暴露并且靠近带负电荷的侧链。 近年来发现，细胞因子的酪氨酸硫酸化 受体分子是某些感染模式的基本要求， HIV-1病毒，并增加其他感染模式的效率（5）。 此外，酪氨酸硫酸化已被证明是活性所必需的。 糖蛋白激素受体家族中的一些亚家族， 在其他亚家族中发挥类似的作用（6）。 因此，我们一直在探索 其他受体家族可能需要酪氨酸硫酸化， 有效或充分的活动。 我们一直在把我们对 酪氨酸硫酸化结合位点与其他生化信息 受体结合位点在蛋白质链中的位置。 我们预测32个七跨膜肽受体的49个酪氨酸是 硫酸化。虽然我们没有将已证实的 硫酸化地点，例如跨物种的聚集和保护，进入我们的 个人资料（职位特定评分矩阵，PSSM），我们的预测网站 然而，它仍然表现出这些特征。观察到的保守性 这表明，有强大的进化压力，以保持选定的 七跨膜肽受体的生物活性。预测 酪氨酸硫酸化位点主要出现在细胞外尾， 细胞外环2，与它们与结合的关联一致的区域 受体的口袋（4）。 通过酪氨酸硫酸化的蛋白质翻译后修饰增强了蛋白质的功能。 细胞外配体-受体相互作用的亲和力在免疫中很重要，

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. This collaboration has been a broadly based examination of tyrosine sulfation, a widespread posttranslational modification of proteins and peptide hormones that pass through the Golgi system of animal cells. When the project began it was limited to a number of the peptide hormones involved in the digestive process and some, for example Cholecystokinin (CCK), active both in the gastrointestinal tract and in the central nervous system. The two tissues express different but closely related receptors. The tyrosine sulfation posttranslational modification has been estimated to occur to about one percent of tyrosine residues in Rat proteins. Our initial papers focused on finding and testing rules that could be used to accurately predict tyrosine sulfation sites (1,2,3). These initial studies led to the conclusions that tyrosylprotein sulfotransferase, the enzyme that catalyzes the sulfation of tyrosine residues in proteins and peptides, has a relatively low substrate specificity and is likely to modify any tyrosine residue that is sufficiently exposed and is near negatively charged side chains. Recently it has been discovered that tyrosine sulfation of specific cytokine receptors molecules is an essential requirement for some modes of infection of the HIV-1 virus and increases the efficiency of other modes of infection (5). Additionally, tyrosine sulfation has been shown to be required for the activity of some subfamilies within the glycoprotein hormone receptors family and seems to play a similar role in other subfamilies (6). Thus we have been exploring the possibility that other receptor families may require tyrosine sulfation for either effective or full activity. We have been correlating our predictions of tyrosine sulfation binding sites with additional biochemical information about the location of receptor binding site within the protein chain. We predict that 49 tyrosines of 32 seven-transmembrane peptide receptors are sulfated. Although we did not incorporate characteristics of confirmed sulfation sites such as clustering and conservation across species into our profile (Position Specific Scoring Matrix, PSSM), our predicted sites nevertheless exhibited these characteristics. The observed conservation suggests that there are strong evolutionary pressures to preserve selected biological activity of seven-transmembrane peptide receptors. The predicted tyrosine sulfation sites predominantly occur in the extracellular tail and extracellular loop 2, regions consistent with their association with binding pockets of the receptor (4). Post-translational modification of proteins by tyrosine sulfation enhances the affinity of extracellular ligand-receptor interactions important in the immune