The Use of Gel Electrophoresis and Mass Spectrometry to Identify Nitroproteins in Nervous System Tumors

Abstract

Protein tyrosine nitration is an important molecular event in nervous system tumor such as glioma and pituitary adenomas. It is the essential step to identify the protein targets and exact modified sites of tyrosine nitration for addressing the biological roles of pro - tein tyrosine nitration in nervous system tumors and discovering effective biomarkers to understand in-depth molecular mechanisms and determine new diagnosis strategy and novel therapeutic targets. One/two-dimensional gel electrophoresis (1DGE, 2DGE), or nitrotyrosine affinity column (NTAC), coupled with tandem mass spectrometry (MS/MS) have been successfully applied in the analysis of nitroproteins in nervous system tumors. This article address the basic concept of protein tyrosine nitration, nitroproteomics meth - odology based on gel electrophoresis/immunoaffinity enrichment and tandem mass spectrometry, and the current status of nitroprotein study in nervous system tumors. The established nitroproteomics approach is easily translated to study other diseases. NO and RNS are important inflammatory mediators [ 15 ]; and (3) increased production of NO, peroxinitrite and superoxide, occurs in nervous system tumors [ 16 ]; (4) higher levels of nitrotyrosine are observed in nervous system tumors than normal tissues with biochemical approaches and immunohistochemical, and only protein nitrotubulin and protein nitro-p53 have been determined in human nervous system tumors [ 17]. Furthermore, the amino acid analog 3-nitrotyrosine due to functional and morphological injury of mouse-neuroblastoma cell lines and rat-glioma cell lines [ 18 ]. These studies demonstrated the importance of protein tyrosine nitration in the pathogenesis of nervous system tumors. Illustrating the functions of nitroproteins might reveal in-depth molecular mechanisms and biological function of tyro sine nitration in human nervous system tumors. Literature-based review and comprehen sive annotation of proteins on the SwissProt website were used to expound the nitroprotein domains/motifs, location of nitrotyrosine sites and possible signaling pathways relevant to nervous system tumors. Nitroproteins took part in multiple biological processes in the devel opment of tumors as follows: (a) tumor cell migration and invasion [ 19 ]; (b) cell proliferation and apoptosis [20]; (c) chemotherapy resistance [ 21 ]; (d) signal transduction [ 22]; (e) phenotypic dedifferentiation [23]; (f) microtubule dynamic stabilization [24 ]; (g) tumor recurrence; (h) others such as immunoreaction and post-transcriptional regulation. Moreover, the discov ery of tyrosine nitration being a reversible reaction [ 25 ] and having a competition between phosphorylation motif [ 26], led us to speculate that dynamic process of protein nitration might also be regulated and controlled. However, no definite target of intervention is found for tyrosine nitration in human nervous system tumors. It takes long time to study tumor-related nitroproteins and to illustrate molecular mechanisms in tumor formation.