POSTTRANSLATIONAL MODIFICATIONS OF CYTOKERATIN PROTEINS

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。我们的目标是确定细胞角蛋白多肽8的磷酸化和o -连接糖基化位点，在质谱水平上研究细胞角蛋白多肽8和可能的细胞角蛋白多肽18。我们希望获得详细的结构信息来支持我们最初的生化数据，表明这种细胞角蛋白有一个单一的n -乙酰氨基葡萄糖残基，我们假设它与丝氨酸相连。我们还希望我们的系统与质谱结合将确定丝氨酸磷酸化状态和o -链糖基化之间是否存在反比关系。细胞角蛋白是研究这个问题的理想系统，因为它们在丝氨酸残基上被严重磷酸化，并且具有o -链糖基化，并且大量存在于细胞中，使它们适合进行质谱测序研究。各种各样的方法正在寻求旨在开发一个强大的质谱策略，用于位点特异性表征核蛋白上的O-GlcNAc残基，以与相同蛋白质上的磷酸化位点进行比较。293 c

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. Our goal is to determine phosphorylation and O-linked glycosylation sites on cytokeratin polypeptide 8, studying cytokeratin polypeptide 8 and possibly cytokeratin polypeptide 18 at the mass spectrometry level. We hope to obtain detailed structural information to support our initial biochemical data indicating that this cytokeratin has a single N-acetylglucosamine residue we presume is linked to serine. We also hope our system coupled with mass spectrometry would determine if there is an inverse relationship between the state of serine phosphorylation and O-linked glycosylation. Cytokeratin proteins make up an ideal system to study this question since they are heavily phosphorylated on serine residues and in addition have the O-linked glycosylation and are present in cells in large quantities, making them amenable for mass spec sequencing studies. A variety of methods are being pursued aimed at development of a robust mass spectrometric strategy for the site specific characterization of O-GlcNAc residues on nuclear proteins for comparison with phosphorylation sites on the same proteins.. 293C