Báo cáo khoa học: Architecture of the Helicobacter pylori Cag-type IV secretion system pdf

MINIREVIEW

Architecture of the Helicobacter pylori Cag-type IV

secretion system

Laurent Terradot1 and Gabriel Waksman2

1 Institut de Biologie et Chimie des Prote´ines, Biologie Structurale des Complexes Macromole´ culaires Bacte´riens, UMR 5086

CNRS Universite´ de Lyon, France

2 Institute of Structural and Molecular Biology, UCL and Birkbeck, London, UK

Introduction

Secretion systems are widespread in bacteria for which

they provide means of exchange between the extra￾and intracellular milieus. Seven different systems have

been described in Gram-negative bacteria [1]. Amongst

them, the type IV secretion systems (T4SS) have raised

considerable attention during the past 10 years because

of their role in bacterial pathogenesis. T4SS are macro￾molecular devices that bacteria use to transport various

Keywords

bacterial pathogenesis; CagA; secretion

system; stomach cancer; translocation

Correspondence

L. Terradot, Institut de Biologie et Chimie

des Prote´ines, Biologie Structurale des

Complexes Macromole´ culaires Bacte´riens,

UMR 5086 CNRS Universite´ de Lyon,

IFR128, 7 Passage du Vercors, F-69367

Lyon Cedex 07, France

Fax: +33 472 722604

Tel: +33 472 722652

E-mail: [email protected] and

G. Waksman, Institute of Structural and

Molecular Biology, UCL and Birkbeck, Malet

Street, London, WC1E 7HX, UK

Fax: +44 (0)207 631 6803

Tel: +44 (0)207 631 6833

E-mail: [email protected] or

[email protected]

(Received 15 November 2010, revised 18

January 2011, accepted 27 January 2011)

doi:10.1111/j.1742-4658.2011.08037.x

Type IV secretion systems (T4SS) are macromolecular assemblies used by

bacteria to transport material across their membranes. T4SS are generally

composed of a set of twelve proteins (VirB1–11 and VirD4). This repre￾sents a dynamic machine powered by three ATPases. T4SS are widespread

in pathogenic bacteria where they are often used to deliver effectors into

host cells. For example, the human pathogen Helicobacter pylori encodes a

T4SS, the Cag-T4SS, which mediates the injection of the toxin CagA. We

review the progress made in the past decade in our understanding of T4SS

architecture. We translate this new knowledge to derive an understanding

of the structure of the H. pylori Cag system, and use recent protein–protein

interaction data to refine this model.

Abbreviations

cagPAI, cytotoxin-associated gene-pathogenicity island; CTD, C-terminal domain; EM, electron microscopy; NTD, N-terminal domain; T4SS,

type IV secretion system.

FEBS Journal 278 (2011) 1213–1222 ª 2011 The Authors Journal compilation ª 2011 FEBS 1213