title: Helicobacter pylori VacA, acting through receptor protein tyrosine phosphatase α, is crucial for CagA phosphorylation in human duodenum carcinoma cell line AZ-521.
abstract: Helicobacter pylori, a major cause of gastroduodenal diseases, produces vacuolating cytotoxin (VacA) and cytotoxin-associated gene A (CagA), which seem to be involved in virulence. VacA exhibits pleiotropic actions in gastroduodenal disorders via its specific receptors. Recently, we found that VacA induced the phosphorylation of cellular Src kinase (Src) at Tyr418 in AZ-521 cells. Silencing of receptor protein tyrosine phosphatase (RPTP)α, a VacA receptor, reduced VacA-induced Src phosphorylation. Src is responsible for tyrosine phosphorylation of CagA at its Glu-Pro-Ile-Tyr-Ala (EPIYA) variant C (EPIYA-C) motif in Helicobacter pylori-infected gastric epithelial cells, resulting in binding of CagA to SHP-2 phosphatase. Challenging AZ-521 cells with wild-type H. pylori induced phosphorylation of CagA, but this did not occur when challenged with a vacA gene-disrupted mutant strain. CagA phosphorylation was observed in cells infected with a vacA gene-disrupted mutant strain after addition of purified VacA, suggesting that VacA is required for H. pylori-induced CagA phosphorylation. Following siRNA-mediated RPTPα knockdown in AZ-521 cells, infection with wild-type H. pylori and treatment with VacA did not induce CagA phosphorylation. Taken together, these results support our conclusion that VacA mediates CagA phosphorylation through RPTPα in AZ-521 cells. These data indicate the possibility that Src phosphorylation induced by VacA is mediated through RPTPα, resulting in activation of Src, leading to CagA phosphorylation at Tyr972 in AZ-521 cells.
authors.affiliation: Department of Bacteriology, Institute of Tropical Medicine, Nagasaki University, 1-12-4, Sakamoto, Nagasaki 852-8523, Japan manakano@nagasaki-u.ac.jp.|Department of International Health, Institute of Tropical Medicine, Nagasaki University, 1-12-4, Sakamoto, Nagasaki 852-8523, Japan.
authors.forename: Masayuki
authors.identifier: 0000-0001-7817-7592
authors.initials: M
authors.lastname: Nakano
authors.affiliation: Department of Molecular Infectiology, Graduate School of Medicine, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8670, Japan.
authors.forename: Kinnosuke
authors.initials: K
authors.lastname: Yahiro
authors.affiliation: Division of Food Hygiene, Department of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Nishi 2-11, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Eiki
authors.initials: E
authors.lastname: Yamasaki
authors.affiliation: Division of Food Hygiene, Department of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Nishi 2-11, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Hisao
authors.initials: H
authors.lastname: Kurazono
authors.affiliation: Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Idaigaoka 1-1, Yufu, Oita 879-5593, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Akada
authors.affiliation: Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Idaigaoka 1-1, Yufu, Oita 879-5593, Japan.|Department of Medicine, Gastroenterology and Hepatology Section, Baylor College of Medicine, Houston, TX 77030, USA.
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Yamaoka
authors.affiliation: Department of Applied Chemistry and Biochemistry, Graduate School of Science and Technology, Kumamoto University, 2-39-1 Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Niidome
authors.affiliation: Division of Microbiology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-0033, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Hatakeyama
authors.affiliation: Medical Education Center, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Department of International Health, Institute of Tropical Medicine, Nagasaki University, 1-12-4, Sakamoto, Nagasaki 852-8523, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Cardiovascular and Pulmonary Branch, NHLBI, National Institutes of Health, Bethesda, MD 20892-1590, USA.
authors.forename: Joel
authors.initials: J
authors.lastname: Moss
authors.affiliation: Division of Medicine and Clinical Science, Tottori University Faculty of Medicine, 86 Nishi-cho, Yonago, Tottori 683-8503, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Isomoto
authors.affiliation: Department of Bacteriology, Institute of Tropical Medicine, Nagasaki University, 1-12-4, Sakamoto, Nagasaki 852-8523, Japan.
authors.forename: Toshiya
authors.initials: T
authors.lastname: Hirayama
mesh_terms: D000942:Antigens, Bacterial / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D045744:Cell Line, Tumor; D004379:Duodenal Neoplasms / Q000378:metabolism* / Q000382:microbiology* / Q000473:pathology; D016481:Helicobacter Infections / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D016480:Helicobacter pylori / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D008954:Models, Biological; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4 / Q000378:metabolism*; D014162:Transfection; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D034741:RNA, Small Interfering; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori; D019000:Phosphotyrosine; D019061:src-Family Kinases; D054630:Receptor-Like Protein Tyrosine Phosphatases, Class 4
keywords: CagA; Helicobacter pylori; VacA