Abstract：
:Infection of colonic epithelial cells by Shigella is associated with the type III secretion system, which serves as a molecular syringe to inject effectors into host cells. This system includes an extracellular needle used as a conduit for secreted proteins. Two of these proteins, IpaB and IpaD, dock at the needle tip to control secretion and are also involved in the insertion of a translocation pore into host cell membrane allowing effector delivery. To better understand the function of IpaD, we substituted thirteen residues conserved among homologous proteins in other bacterial species. Generated variants were tested for their ability to surface expose IpaB and IpaD, to control secretion, to insert the translocation pore, and to invade host cells. In addition to a first group of seven ipaD variants that behaved similarly to the wild-type strain, we identified a second group with mutations V314D and I319D that deregulated secretion of all effectors, but remained fully invasive. Moreover, we identified a third group with mutations Y153A, T161D, Q165L and Y276A, that exhibited increased levels of translocators secretion, pore formation, and cell entry. Altogether, our results offer a better understanding of the role of IpaD in the control of Shigella virulence.
journal_name
Microbes Infectjournal_title
Microbes and infectionauthors
Meghraoui A,Schiavolin L,Allaoui Adoi
10.1016/j.micinf.2014.03.010subject
Has Abstractpub_date
2014-07-01 00:00:00pages
532-9issue
7eissn
1286-4579issn
1769-714Xpii
S1286-4579(14)00039-2journal_volume
16pub_type
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