title: Identification of RKIP as a differentially tyrosine-phosphorylated protein in nasopharyngeal carcinoma and normal nasopharyngeal epithelial tissues by phosphoproteomic approach.
abstract: OBJECTIVE
  To screen for differentially tyrosine-phosphorylated proteins between nasopharyngeal carcinoma (NPC) and normal nasopharyngeal epithelial tissues (NNET) to provide a basis for elucidate the molecular mechanisms of NPC carcinogenesis.
  
  
  METHODS
  Two-dimensional (2-D) electrophoresis was applied to separate proteins from NPC and NNET, respectively, and 2-D Western blotting was performed to detect tyrosine-phosphorylated proteins using antiphosphotyrosine antibody. Differentially tyrosine-phosphorylated proteins were identified by electrospray ionization-quadrupole time-of-flight MS (ESI-Q-TOF MS). NetPhos software was used to predict the tyrosine-phosphorylation sites of the identified proteins, and Western blotting was used to detect the tyrosine-phosphorylated levels of RKIP in NPC and NNET.
  
  
  RESULTS
  Twenty-five differentially tyrosine-phosphorylated proteins in the two types of tissues were found, 13 of which were identified by ESI-Q-TOF MS. Among the 13 identified proteins, tyrosine-phosphorylated levels of 7 proteins were increased, and those of 6 proteins were decreased in NPC compared with NNET. NetPhos software prediction showed that all the 13 identified proteins contained tyrosine phosphorylation sites, and the differentially tyrosine-phosphorylated level of RKIP in NPC and NNET was confirmed.
  
  
  CONCLUSIONS
  The 13 differentially tyrosine-phosphorylated proteins may be involved in the development and progression of NPC.
authors.affiliation: Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha, 410008, Hunan Province, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.forename: Can-E
authors.initials: CE
authors.lastname: Tang
authors.forename: Guo-Liang
authors.initials: GL
authors.lastname: Ouyang
authors.forename: Lin
authors.initials: L
authors.lastname: Ruan
authors.forename: Mao-Yu
authors.initials: MY
authors.lastname: Li
authors.forename: Peng-Fei
authors.initials: PF
authors.lastname: Zhang
authors.forename: Cui
authors.initials: C
authors.lastname: Li
authors.forename: Hong
authors.initials: H
authors.lastname: Yi
authors.forename: Fang
authors.initials: F
authors.lastname: Peng
authors.forename: Jian-Ling
authors.initials: JL
authors.lastname: Li
authors.forename: Zhu-Chu
authors.initials: ZC
authors.lastname: Chen
authors.forename: Zhi-Qiang
authors.initials: ZQ
authors.lastname: Xiao
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism; D015153:Blotting, Western; D015180:Electrophoresis, Gel, Two-Dimensional; D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000378:metabolism*; D009305:Nasopharynx / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000378:metabolism; D049488:Phosphatidylethanolamine Binding Protein / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D040901:Proteomics; D021241:Spectrometry, Mass, Electrospray Ionization; D014443:Tyrosine / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; C511482:PEBP1 protein, human; D049488:Phosphatidylethanolamine Binding Protein; D010750:Phosphoproteins; D014443:Tyrosine