Altered states: Involvement of phosphorylated CagA in the induction of host cellular growth changes by
            <i>Helicobacter pylori</i>

Segal, E.; Cha, John; Lo, Jonathan; Falkow, Stanley; Tompkins, Lucy S.

doi:10.1073/pnas.96.25.14559

Cited by 722 publications

(677 citation statements)

References 13 publications

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“…When H. pylori cells carrying the cag pathogenicity island attach to cultured AGS cells, a human gastric adenocarcinoma epithelial cell line, they induce the 'hummingbird phenotype', the features of which include cytoskeletal rearrangements, cell elongation and increased cell motility 84 (Fig. 4).…”

Section: H Pylori Caga Transfermentioning

confidence: 99%

The versatile bacterial type IV secretion systems

Cascales¹,

Christie²

2003

Nat Rev Microbiol

596

559

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Bacteria use type IV secretion systems for two fundamental objectives related to pathogenesisgenetic exchange and the delivery of effector molecules to eukaryotic target cells. Whereas gene acquisition is an important adaptive mechanism that enables pathogens to cope with a changing environment during invasion of the host, interactions between effector and host molecules can suppress defence mechanisms, facilitate intracellular growth and even induce the synthesis of nutrients that are beneficial to bacterial colonization. Rapid progress has been made towards defining the structures and functions of type IV secretion machines, identifying the effector molecules, and elucidating the mechanisms by which the translocated effectors subvert eukaryotic cellular processes during infection. The year 2003 marks the fiftieth anniversary of the first description of a TYPE IV SECRETION (T4S)SYSTEM: the CONJUGATION apparatus of the F plasmid 1 . This is a dynamic bacterial surface organelle, the activities of which are now known to include the contact-dependent delivery of DNA to bacterial recipients and the assembly and retraction of a conjugal PILUS 2 . In the past decade, reports describing systems that are ancestrally related to the F-transfer system and other conjugation machines have emerged. Instead of mediating DNA transfer between bacteria, these systems deliver DNA or protein substrates, known as effectors, to eukaryotic target cells during infection [3][4][5] . More recently, several new T4S systems have been described that are also ancestrally related to the conjugation machines, but these systems mediate the exchange of DNA with the extracellular milieu [6][7][8] . Collectively, this diversity of function in the face of a common ancestry makes the T4S machines attractive subjects for comparative studies that explore the dynamics of organelle assembly and action. Additionally, from a medical perspective, it is of enormous interest to develop a detailed understanding of how the inter-kingdom transfer of type IV effector molecules contributes to pathogenesis. This review will summarize the recent advances in our knowledge of T4S, NIH Public Access Author ManuscriptNat Rev Microbiol. Author manuscript; available in PMC 2013 December 27. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscriptwith an emphasis on machine structure and function, and the activities of effectors after translocation into the eukaryotic host. The T4S familyThis fascinatingly versatile translocation family can be classified into three subfamilies, each of which contributes in unique ways to pathogenesis ( Fig. 1; Table 1). The largest subfamily, the conjugation systems, are found in most species of Gram-negative and Grampositive bacteria. These systems mediate DNA transfer both within and between phylogenetically diverse species, and some systems even deliver DNA to fungi, plants and human cells 2,9-13 . Conjugation is an important contributor to genome plasticity, and therefore bacterial fitness under changing en...

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Section: H Pylori Caga Transfermentioning

confidence: 99%

The versatile bacterial type IV secretion systems

Cascales¹,

Christie²

2003

Nat Rev Microbiol

596

559

View full text Add to dashboard Cite

show abstract

“…Following the attachment of cagA-positive H. pylori to the surface of gastric epithelial cells, CagA is delivered from the bacterium into the cytoplasm of host cells through the type IV secretion system (Segal et al, 1999;Asahi et al, 2000;Backert et al, 2000;Odenbreit et al, 2000;Stein et al, 2000). This process is mediated at least partly through an interaction of H. pylori CagL with integrins (Kwok et al, 2007).…”

Section: Translocation Of H Pylori Caga Into Gastric Epithelial Cellsmentioning

confidence: 99%

“…SHP-2 has an important function in signal transduction downstream of growth factor/cytokine receptors that promotes cell proliferation, morphogenesis and motility (Neel et al, 2003). Consequently, expression of CagA in gastric epithelial cells causes morphological transformation termed the hummingbird phenotype, which is characterized by elongated cell shape with Linking epithelial polarity and carcinogenesis by H. pylori CagA M Hatakeyama dramatic cytoskeletal rearrangements (Segal et al, 1999;Higashi et al, 2002a). An important question is the nature of the substrates that are dephosphorylated by CagA-activated SHP-2 in the morphogenetic activity of CagA.…”

Section: Interaction Of Caga With Shp-2 Oncoproteinmentioning

confidence: 99%

Linking epithelial polarity and carcinogenesis by multitasking Helicobacter pylori virulence factor CagA

Hatakeyama

2008

Oncogene

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“…The cagA gene product CagA is delivered into H. pylori-attached gastric epithelial cells via the type IV secretion system (Segal et al, 1999;Odenbreit et al, 2000). Upon tyrosine phosphorylation by Src family kinases, CagA binds and activates SHP-2 tyrosine phosphatase to induce an elongated cell shape termed the 'hummingbird phenotype' (Higashi et al, 2002(Higashi et al, , 2004.…”

Section: Introductionmentioning

confidence: 99%

Helicobacter pylori CagA interacts with E-cadherin and deregulates the β-catenin signal that promotes intestinal transdifferentiation in gastric epithelial cells

et al. 2007

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Infection with Helicobacter pylori cagA-positive strains is associated with gastric adenocarcinoma. Intestinal metaplasia is a precancerous lesion of the stomach characterized by transdifferentiation of the gastric mucosa to an intestinal phenotype. The H. pylori cagA gene product, CagA, is delivered into gastric epithelial cells, where it undergoes tyrosine phosphorylation by Src family kinases. Tyrosine-phosphorylated CagA specifically binds to and activates SHP-2 phosphatase, thereby inducing cell-morphological transformation. We report here that CagA physically interacts with E-cadherin independently of CagA tyrosine phosphorylation. The CagA/E-cadherin interaction impairs the complex formation between E-cadherin and b-catenin, causing cytoplasmic and nuclear accumulation of b-catenin. CagA-deregulated b-catenin then transactivates b-catenin-dependent genes such as cdx1, which encodes intestinal specific CDX1 transcription factor. In addition to b-catenin signal, CagA also transactivates p21 WAF1/Cip1 , again, in a phosphorylation-independent manner. Consequently, CagA induces aberrant expression of an intestinal-differentiation marker, goblet-cell mucin MUC2, in gastric epithelial cells that have been arrested in G1 by p21 WAF1/Cip1 . These results indicate that perturbation of the E-cadherin/b-catenin complex by H. pylori CagA plays an important role in the development of intestinal metaplasia, a premalignant transdifferentiation of gastric epithelial cells from which intestinal-type gastric adenocarcinoma arises.

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Altered states: Involvement of phosphorylated CagA in the induction of host cellular growth changes by Helicobacter pylori

Cited by 722 publications

References 13 publications

The versatile bacterial type IV secretion systems

The versatile bacterial type IV secretion systems

Linking epithelial polarity and carcinogenesis by multitasking Helicobacter pylori virulence factor CagA

Helicobacter pylori CagA interacts with E-cadherin and deregulates the β-catenin signal that promotes intestinal transdifferentiation in gastric epithelial cells

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