Linked Life Data

15225323

Source:http://linkedlifedata.com/resource/pubmed/id/15225323

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2004-6-30
pubmed:abstractText
Expression of the Pseudomonas aeruginosa type III secretion system (TTSS) is coupled to the secretion status of the cells. Environmental signals such as calcium depletion activate the type III secretion channel and, as a consequence, type III gene transcription is derepressed. Two proteins, ExsA and ExsD, were shown previously to play a role in coupling transcription to secretion. ExsA is an activator of TTSS gene transcription, and ExsD is an anti-activator of ExsA. In the absence of environmental secretion cues, ExsD binds ExsA and inhibits transcription. Here, we describe the characterization of ExsC as an anti-anti-activator of TTSS expression. Transcription of the TTSS is repressed in an exsC mutant and is derepressed upon ExsC overexpression. The dependence on exsC for transcription is relieved in the absence of exsD, suggesting that ExsC and ExsD function together to regulate transcription. Consistent with this idea, ExsC interacts with ExsD in bacterial two-hybrid and co-purification assays. We propose a model in which the anti-anti-activator (ExsC) binds to and sequesters the anti-activator (ExsD) under low Ca(2+) conditions, freeing ExsA and allowing for transcription of the TTSS. The P. aeruginosa system represents the first example of an anti-activator/anti-anti-activator pair controlling transcription of a TTSS.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jul
pubmed:issn
0950-382X
pubmed:author
pubmed:issnType
Print
pubmed:volume
53
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
297-308
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2004
pubmed:articleTitle
A novel anti-anti-activator mechanism regulates expression of the Pseudomonas aeruginosa type III secretion system.
pubmed:affiliation
Department of Microbiology, W. M. Keck Microbial Communities and Cell Signaling Program, University of Iowa, 540B Eckstein Medical Research Building, Iowa City, IA 52242, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't