| Domains of the Shigella flexneri type III secretion system IpaB protein involved in secretion regulation. | |
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MedLine Citation:
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PMID: 20937761 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Type III secretion systems (T3SSs) are key determinants of virulence in many Gram-negative bacterial pathogens. Upon cell contact, they inject effector proteins directly into eukaryotic cells through a needle protruding from the bacterial surface. Host cell sensing occurs through a distal needle "tip complex," but how this occurs is not understood. The tip complex of quiescent needles is composed of IpaD, which is topped by IpaB. Physical contact with host cells initiates secretion and leads to assembly of a pore, formed by IpaB and IpaC, in the host cell membrane, through which other virulence effector proteins may be translocated. IpaB is required for regulation of secretion and may be the host cell sensor. It binds needles via its extreme C-terminal coiled coil, thereby likely positioning a large domain containing its hydrophobic regions at the distal tips of needles. In this study, we used short deletion mutants within this domain to search for regions of IpaB involved in secretion regulation. This identified two regions, amino acids 227 to 236 and 297 to 306, the presence of which are required for maintenance of IpaB at the needle tip, secretion regulation, and normal pore formation but not invasion. We therefore propose that removal of either of these regions leads to an inability to block secretion prior to reception of the activation signal and/or a defect in host cell sensing. |
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Authors:
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Da-Kang Shen; Saroj Saurya; Carolin Wagner; Hiroaki Nishioka; Ariel J Blocker |
Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't Date: 2010-10-11 |
Journal Detail:
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Title: Infection and immunity Volume: 78 ISSN: 1098-5522 ISO Abbreviation: Infect. Immun. Publication Date: 2010 Dec |
Date Detail:
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Created Date: 2010-11-16 Completed Date: 2010-12-15 Revised Date: 2011-07-28 |
Medline Journal Info:
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Nlm Unique ID: 0246127 Medline TA: Infect Immun Country: United States |
Other Details:
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Languages: eng Pagination: 4999-5010 Citation Subset: IM |
Affiliation:
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School of Cellular & Molecular Medicine, University of Bristol, Bristol BS8 1TD, United Kingdom. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Antigens, Bacterial
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genetics,
physiology Bacterial Adhesion / physiology Bacterial Proteins / physiology* Bacterial Secretion Systems / genetics, physiology* Dysentery, Bacillary / microbiology* Erythrocyte Membrane / microbiology Gene Expression Regulation, Bacterial / genetics, physiology Hela Cells Humans Microscopy, Fluorescence Protein Structure, Tertiary / genetics, physiology Sequence Deletion / genetics Shigella flexneri / genetics, pathogenicity* |
| Grant Support | |
ID/Acronym/Agency:
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G0701243//Medical Research Council; K22AI001847/AI/NIAID NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Antigens, Bacterial; 0/Bacterial Proteins; 127384-62-7/ipaB protein, Shigella; 127384-63-8/IpaC protein, Shigella |
| Comments/Corrections | |
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