tailieunhanh - Báo cáo khoa học: Structural and functional aspects of unique type IV secretory components in the Helicobacter pylori cag-pathogenicity island

Helicobacter pylori cytotoxin-associated gene-pathogenicity island (cagPAI) is responsible for the secretion of the CagA effector through a type IV secretion system (T4SS) apparatus, as well as of peptidoglycan and possibly other not yet identified factors. | IFEBS Journal MINIREVIEW Structural and functional aspects of unique type IV secretory components in the Helicobacter pylori cag-pathogenicity island Laura Cendron1 and Giuseppe Zanotti2 1 Department of BiologicalChemistry University of Padua Italy 2 Venetian Institute of Molecular Medicine VIMM Padua Italy Keywords 3D structure Cag proteins gastric cancer Helicobacter pylori type IV secretion system Correspondence G. Zanotti Department of Biological Chemistry University of Padua Viale G. Colombo 3 35121 Padua Italy Fax 39 0498073310 Tel 39 0498276409 E-mail Received 16 November 2010 revised 10 January 2011 accepted 27 January 2011 doi Helicobacter pylori cytotoxin-associated gene-pathogenicity island cagPAI is responsible for the secretion of the CagA effector through a type IV secretion system T4SS apparatus as well as of peptidoglycan and possibly other not yet identified factors. Twenty-nine different polypeptide chains are encoded by this cluster of genes although only some of them show a significant similarity with the constitutive elements of well characterized secretion systems from other bacteria. The other cagPAI components represent almost unique proteins in this scenario. The majority of the T4SS include approximately fifteen components taking into account either the transmembrane complex subunits ATPases or substrate factors. The composition of the cagPAI is very complex it includes proteins most likely involved at different levels in the pilus assembly stabilization and processing of secreted substrate as well as regulatory particles possibly involved in the control of the entire apparatus. Despite recent findings with respect to components that play a role in the interaction with the host cell the function of several cagPAI proteins remains unclear or unknown. This is particularly true for those that represent unique members with no clear similarity to those of other T4SS and no obvious .