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Functional interaction and structural characteristics of unique components of Helicobacter pylori T4 SS
Author(s) -
Merino Enrique,
FloresEncarnación Marcos,
AguilarGutiérrez Germán Rubén
Publication year - 2017
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.14092
Subject(s) - caga , secretion , pathogenicity island , helicobacter pylori , biology , chromosomal translocation , virulence , gene , microbiology and biotechnology , genetics , biochemistry
The Helicobacter pylori infection of the human gastric mucosa causes chronic active gastritis and peptic ulcers and is associated with the development of gastric cancer. Epidemiological studies show that these gastric diseases are related to virulent H. pylori strains that harbor the cytotoxin‐associated gene pathogenicity island ( cag PAI ). The cag PAI is a DNA insertion in the H. pylori chromosome that encodes ~ 27 proteins, including the oncoprotein CagA. Approximately 20 of these proteins have been designated as cag type IV secretion system (T4 SS ) components. However, only 11 of these proteins share function, structure, and/or sequence similarities with the prototypical VirB/VirD4 T4 SS of Agrobacterium tumefaciens . The VirB/VirD4 orthologs of the cag T4 SS of H. pylori are required for CagA translocation and stimulate the gastric epithelial cells to produce and secrete interleukin‐8 ( IL ‐8). The cag PAI encodes eight additional proteins, such as Cag3 (Cagδ/ HP 0522), CagM (Cag16/ HP 0537), CagU (Cag11/ HP 0531), CagI (Cag19/ HP 0540), and CagH (Cag20/ HP 0541), which are also required for the translocation of CagA and IL ‐8 secretion, meanwhile CagF (Cag22/ HP 0543), CagG (Cag21/ HP 0542), and CagZ (Cag6/ HP 0526) are just required for the translocation of CagA. However, relatively little is known about their functions and structural organization because they exhibit a nondetectable sequence similarity with T4 SS components in the current databases. In this review, we conducted an exhaustive analysis of the literature to present the biochemistry, putative role, localization, and interactions of each of these eight additional cag T4 SS components.