Identification of Cellular Proteins Being Tyrosine-Phosphorylated in Helicobacter pylori-Infected AGS Gastric Epithelial Cells

• Main Authors: Shin-Yi Du, 杜信誼
• Other Authors: Hua-Wen Fu
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/78440813370967567217

碩士 === 國立清華大學 === 分子與細胞生物研究所 === 93 === Abstract Helicobacter pylori, a spiral, gram-negative, microaerophilic bacterium that colonizes the human stomach, is thought to infect about half of the world’s population. However, little is known about the molecular mechanisms by which H. pylori exerts the pathogenesis. Base on our knowledge, most of the proteins involved in the signaling events might be regulated by phosphorylation. To determine whether cellular proteins are phosphorylated after H. pylori infection, the proteins being tyrosine-phosphorylated in AGS cells after H. pylori infection were examined by Western blot analysis. I found that several proteins in AGS cells were phosphorylated or dephosphorylated at tyrosine residues after H. pylori infection. Many of these tyrosine-dephosphorylated proteins belong to CagA (cytotoxin-associated gene A)-dependent event. To further identify these tyrosine-phosphorylated or dephosphorylated proteins, I applied the immunoprecipitation technique to isolate these proteins and resolved them by SDS-PAGE followed by SYPRO Ruby staining. Eight bands of interest were excised from the gel and subjected to in-gel tryptic digestion. After analyzing by MALDI-MS, M2-type pyruvate kinase was identified as the most possible protein which was phosphorylated in response to H. pylori infection.