RRC ID 35276
Author Masi M, Wandersman C.
Title Multiple signals direct the assembly and function of a type 1 secretion system.
Journal J. Bacteriol.
Abstract Type 1 secretion systems (T1SS) are present in a wide range of Gram-negative bacteria and are involved in the secretion of diverse substrates such as proteases, lipases, and hemophores. T1SS consist of three proteins: an inner membrane ABC (ATP binding cassette) protein, a periplasmic adaptor, and an outer membrane channel of the TolC family. Assembly of the tripartite complex is transient and induced upon binding of the substrate to the ABC protein. It is generally accepted that T1SS-secreted proteins have a C-terminal secretion signal required for secretion and that this signal interacts with the ABC protein. However, we have previously shown that for the Serratia marcescens hemophore HasA, interactions with the ABC protein and subsequent T1SS assembly require additional regions. In this work, we characterize these regions and demonstrate that they are numerous, distributed throughout the HasA polypeptide, and most likely linear. Together with the C-terminal signal, these elements maximize the secretion of HasA. The data also show that the C-terminal signal of HasA triggers HasD-driven ATP hydrolysis, leading to disassembly of the complex. These data support a model of type 1 secretion involving a multistep interaction between the substrate and the ABC protein that stabilizes the assembled secretion system until the C terminus is presented. This model also supports tight coupling between synthesis and secretion.
Volume 192(15)
Pages 3861-9
Published 2010-8
DOI 10.1128/JB.00178-10
PII JB.00178-10
PMID 20418390
PMC PMC2916380
MeSH Adenosine Triphosphate / metabolism Bacterial Proteins / genetics Bacterial Proteins / metabolism* Escherichia coli / physiology* Gene Expression Regulation, Bacterial Models, Molecular Mutation Protein Folding Protein Transport Secretory Pathway / physiology* Signal Transduction / physiology*
IF 3.234
Times Cited 16
Prokaryotes E. coli ?