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Abstract
Type III secretion systems (T3SSs) are protein injection devices essential for the interaction of many Gram-negative bacteria with eukaryotic cells. While Shigella assembles its T3SS when the environmental conditions are appropriate for invasion, secretion is only activated after physical contact with a host cell. First, the translocators are secreted to form a pore in the host cell membrane, followed by effectors which manipulate the host cell. Secretion activation is tightly controlled by conserved T3SS components: the needle tip proteins IpaD and IpaB, the needle itself and the intracellular gatekeeper protein MxiC. To further characterize the role of IpaD during activation, we combined random mutagenesis with a genetic screen to identify ipaD mutant strains unable to respond to host cell contact. Class II mutants have an overall defect in secretion induction. They map to IpaD's C-terminal helix and likely affect activation signal generation or transmission. The Class I mutant secretes translocators prematurely and is specifically defective in IpaD secretion upon activation. A phenotypically equivalent mutant was found in mxiC. We show that IpaD and MxiC act in the same intracellular pathway. In summary, we demonstrate that IpaD has a dual role and acts at two distinct locations during secretion activation.
Original language | English |
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Pages (from-to) | 690-706 |
Journal | Molecular Microbiology |
Volume | 87 |
Issue number | 3 |
Early online date | 11 Jan 2013 |
DOIs | |
Publication status | Published - Feb 2013 |
Bibliographical note
© 2013 Blackwell Publishing Ltd.Fingerprint
Dive into the research topics of 'Shigella IpaD has a dual role: signal transduction from the type III secretion system needle tip and intracellular secretion regulation'. Together they form a unique fingerprint.Projects
- 2 Finished
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Bacterial type III secretion systems: from structure to function
Blocker, A. J.
28/01/12 → 28/05/15
Project: Research
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