Previous Article | Next Article ![]()
Infection and Immunity, November 2000, p. 6449-6456, Vol. 68, No. 11
Molecular Infectious Diseases Group,
Department of Paediatrics,1 and
Department of Medical Microbiology,2
Imperial College School of Medicine, St. Mary's Campus, London W2 1PG,
United Kingdom
Received 5 July 2000/Returned for modification 9 August
2000/Accepted 18 August 2000
DsbA, a disulfide bond catalyst, is necessary for realization of
the pathogenic potential of Shigella flexneri. Sh42, a
mutant strain differing from wild-type M90TS solely because it
expresses nonfunctional DsbA33G (substitution for 33C at the active
site), secreted less IpaB and IpaC than M90TS in response to various stimuli in vitro. A kinetic study demonstrated that Sh42 responded more
slowly to Congo red than M90TS. By modulating relative concentrations of functional and nonfunctional DsbA within bacteria, functional enzyme
has been shown to be necessary for intercellular spread. By confocal
microscopy, M90TS dividing in protrusions was shown to secrete Ipa
proteins from the septation furrow, anticipating lysis of protrusions,
while Sh42 showed minimal Ipa secretion in this location. In the light
of a previous demonstration that DsbA is not necessary for entry of
epithelial cells, we conclude that a role in virulence of this
disulfide bond catalyst lies in facilitating secretion of Ipa proteins
specifically within epithelial protrusions, in turn allowing
cell-to-cell spread of S. flexneri.
0019-9567/00/$04.00+0
Copyright © 2000, American Society for Microbiology. All rights reserved.
Key Role for DsbA in Cell-to-Cell Spread of
Shigella flexneri, Permitting Secretion of Ipa Proteins into
Interepithelial Protrusions
and
*
Corresponding author. Mailing address: Molecular
Infectious Diseases Group, Department of Paediatrics, Imperial College
School of Medicine, St. Mary's Campus, London W2 1PG, United Kingdom. Phone: (44) 20 7886 6340. Fax: (44) 20 7886 6284. E-mail:
jun.yu{at}ic.ac.uk.
Present address: Service de Microbiologie, Hôpital Saint
Louis, 75475 Paris Cedex 10, France.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»