Affiliation:
1. Section of Microbial Pathogenesis, Boyer Center for Molecular Medicine, Yale School of Medicine, New Haven, Connecticut 06536-0812
Abstract
ABSTRACT
Several pathogenic bacteria have evolved a specialized protein secretion system termed type III to secrete and deliver effector proteins into eukaryotic host cells.
Salmonella enterica
serovar Typhimurium uses one such system to mediate entry into nonphagocytic cells. This system is composed of more than 20 proteins which are encoded within a pathogenicity island (SPI-1) located at centisome 63 of its chromosome. A subset of these components form a supramolecular structure, termed the needle complex, that resembles the flagellar hook-basal body complex. The needle complex is composed of a multiple-ring cylindrical base that spans the bacterial envelope and a needle-like extension that protrudes from the bacterial outer surface. Although the components of this structure have been identified, little is known about its assembly. In this study we examined the effect of loss-of-function mutations in each of the type III secretion-associated genes encoded within SPI-1 on the assembly of the needle complex. This analysis indicates that the assembly of this organelle occurs in discrete, genetically separable steps. A model for the assembly pathway of this important organelle is proposed that involves a
sec
-dependent step leading to the assembly of the base substructure followed by a
sec
-independent process resulting in the assembly of the needle portion.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Cited by
156 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献