Basic–Alimentary TractHelicobacter pylori CagA protein activates serum response element–driven transcription independently of tyrosine phosphorylation☆,☆☆
Section snippets
Cell line
HeLa cells, a human cervical carcinoma cell line, were obtained from the Riken Cell Bank (Tsukuba, Japan). Cells were grown at 37°C in 5% CO2 in Dulbecco's modified Eagle medium supplemented with 100 U/mL penicillin, 100 μg/mL streptomycin, and 10% fetal bovine serum. Three gastric carcinoma cell lines—AGS, TMK1, and MKN45 cells—were obtained and grown as previously described.19, 22, 30
Plasmids
The full-length cagA gene and its various fragments were amplified from H. pylori strain 26695 by polymerase
Helicobacter CagA protein activates serum response element–driven transcription in epithelial cells
To investigate the roles of translocated CagA protein in epithelial cells, we first transfected HeLa cells with the expression vector pTX-CagA, which contains the H. pylori ATCC26695 cagA gene. As shown by immunoblotting with an anti-CagA antibody, CagA was expressed in a dose-dependent manner (Figure 1A).
Discussion
Several studies have revealed that the type I strain of H. pylori transports CagA protein into host epithelial cells via the bacterial PAI secretion system, and that translocated CagA protein is phosphorylated on a Tyr residue.38, 39, 40, 41 In these reports, the function of CagA protein is linked to cellular cytoskeletal rearrangements through Tyr phosphorylation. In this study we have demonstrated a new role for translocated CagA as a regulator of cytoplasmic signaling and gene transcription.
Acknowledgements
The authors thank Mitsuko Tsubouchi for her excellent technical assistance.
References (67)
- et al.
Unidentified curved bacilli in the stomach of patients with gastritis and peptic ulceration
Lancet
(1984) - et al.
Meta-analysis of the relationship between Helicobacter pylori seropositivity and gastric cancer
Gastroenterology
(1998) - et al.
Apoptosis in gastric epithelium induced by Helicobacter pylori infection: implications in gastric carcinogenesis
Am J Gastroenterol
(2001) - et al.
Helicobacter pylori infection activates NF-kappa B in gastric epithelial cells
Gastroenterology
(1997) - et al.
Helicobacter pylori activates NF-κB through a signaling pathway involving IκB kinases, NF-κB–inducing kinase, TRAF2, and TRAF6 in gastric cancer cells
Gastroenterology
(2000) - et al.
Helicobacter pylori activates mitogen-activated protein kinase cascades and induces expression of the proto-oncogenes c-fos and c-jun
J Biol Chem
(2000) Ternary complex factors: growth factor–regulated transcriptional activators
Curr Opin Genet Dev
(1994)- et al.
v-Src activates mitogen-responsive transcription factor Egr-1 via serum response elements
J Biol Chem
(1991) - et al.
Relationship between the cagA 3' repeat region of Helicobacter pylori, gastric histology, and susceptibility to low pH
Gastroenterology
(1999) - et al.
Large isoform of hepatitis delta antigen activates serum response factor-associated transcription
J Biol Chem
(2000)
The SRF accessory protein Elk-1 contains a growth factor–regulated transcriptional activation domain
Cell
Signaling—2000 and beyond
Cell
SH2 domains, interaction modules and cellular wiring
Trends Cell Biol
Increased MAPK activity and MKP-1 overexpression in human gastric adenocarcinoma
Biochem Biophys Res Commun
Interaction of invasive bacteria with host signaling pathways
Curr Opin Cell Biol
Enteropathogenic E. coli (EPEC) transfers its receptor for intimate adherence into mammalian cells
Cell
typhimurium encodes an activator of Rho GTPases that induces membrane ruffling and nuclear responses in host cells
Cell
Unidentified curved bacilli on gastric epithelium in active chronic gastritis
Lancet
Helicobacter pylori and peptic ulcer disease
N Engl J Med
Helicobacter pylori infection and gastric carcinoma among Japanese Americans in Hawaii
N Engl J Med
Helicobacter pylori infection and the development of gastric cancer
N Engl J Med
IARC monographs on the evaluation of carcinogenic risks to humans
Interleukin-8 expression in Helicobacter pylori–infected, normal, and neoplastic gastroduodenal mucosa
J Clin Pathol
Induction of gastric epithelial apoptosis by Helicobacter pylori
Gut
Helicobacter pylori increases proliferation of gastric epithelial cells
Gut
Helicobacter pylori cagA+ strains and dissociation of gastric epithelial cell proliferation from apoptosis
J Natl Cancer Inst
Increase in proliferation and apoptosis of gastric epithelial cells early in the natural history of Helicobacter pylori infection
Am J Pathol
cag, a pathogenicity island of Helicobacter pylori, encodes type I-specific and disease-associated virulence factors
Proc Natl Acad Sci U S A
Infection with Helicobacter pylori strains possessing cagA is associated with an increased risk of developing adenocarcinoma of the stomach
Cancer Res
Structure of cag pathogenicity island in Japanese Helicobacter pylori isolates
Gut
Activation of IL-8 gene expression by Helicobacter pylori is regulated by transcription factor nuclear factor-κB in gastric epithelial cells
J Immunol
Differential activation of mitogen-activated protein kinases in AGS gastric epithelial cells by cag+ and cag- Helicobacter pylori
J Immunol
Helicobacter pylori–induced transactivation of SRE and AP-1 through the ERK signaling pathway in gastric cancer cells
Gut
Cited by (68)
Hepatocyte growth factor in physiology and infectious diseases
2017, CytokineCitation Excerpt :Once within gastric epithelial cells, some CagA molecules are tyrosine-phosphorylated by the Src/Abl kinase. Although the importance of CagA phosphorylation has been studied intensively, recently accumulating information suggests that nonphosphorylated CagA also contributes to the development of H. pylori-associated gastric illnesses, which includes gastric cancer [86,87]. Suzuki et al. showed that nonphosphorylated CagA is involved in interacting with activated Met, leading to the sustained activation of PI3-K/Akt signaling in response to H. pylori infection.
Clinical relevance of Helicobacter pylori vacA and cagA genotypes in gastric carcinoma
2014, Best Practice and Research: Clinical GastroenterologyCitation Excerpt :CagA is the only protein so far described to be injected through the cag T4SS into the host cell cytoplasm [67]. Upon injection, unphosphorylated CagA interacts with host cell proteins, mainly causing disruption of cell–cell junctions, alteration of epithelial cell polarity, and induction of pro-inflammatory and mitogenic responses [68–73]. CagA may also undergo phosphorylation by the Src and Abl family kinases on tyrosine residues within Glu-Pro-Ile-Tyr-Ala (EPIYA) motifs [74–78].
Increased miR-222 in H. pylori-associated gastric cancer correlated with tumor progression by promoting cancer cell proliferation and targeting RECK
2012, FEBS LettersCitation Excerpt :International Agency for Research on Cancer categorized Helicobacter pylori as a group 1 carcinogen for gastric cancer in 1994 [2]. To date, evidence linking H. pylori to gastric cancer has continued to accumulate [3,4]. However, the mechanism involved in the carcinogenesis of gastric cancer induced by H. pylori remains poorly defined.
A novel inhibitory domain of Helicobacter pylori protein CagA reduces CagA effects on host cell biology
2011, Journal of Biological ChemistryCitation Excerpt :As a result, epithelial gastric carcinoma cells elicit growth factor-like responses such as cell scattering, elongation, and migration (14–18). CagA also has phosphorylation-independent effects on host cell signaling pathways (19–22). CM/CRPIA motifs in the C terminus of CagA contribute to cell scattering and mediate NF-κB and TCF/β-catenin3 transcriptional activity (23).
Helicobacter pylori
2010, Sleisenger and Fordtran’s Gastrointestinal and Liver Disease- 2 Volume Set: Pathophysiology, Diagnosis, Management, Expert Consult Premium Edition - Enhanced Online Features and PrintHelicobacter pylori CagA-mediated ether lipid biosynthesis promotes ferroptosis susceptibility in gastric cancer
2024, Experimental and Molecular Medicine
- ☆
Address requests for reprints to: Yoshihiro Hirata, M.D., Department of Gastroenterology, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. e-mail: [email protected]; fax: (81) 3-3814-0021.
- ☆☆
This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, Sports, and Culture of Japan.