A proteinaceous gene regulatory thermometer in Salmonella.
Novel utilization of the coiled-coil motif is presented that enables TlpA, an autoregulatory repressor protein in Salmonella, to sense temperature shifts directly and thereby to modulate the extent of transcription repression. Salmonella cells shifted to higher temperatures, such as those encountered at host entry, showed derepressed tlpA activity. tlpA::lacZ fusions indicated that the promoter itself is insensitive to thermal shifts and that transcription control was exerted by the autorepressor TlpA only. In vitro studies with highly purified TlpA showed concentration and temperature dependence for both fully folded conformation and function, indicating that the thermosensing in TlpA is based on monomer-to-coiled-coil equilibrium.
Hurme
R
R
Microbiology and Tumor Biology Center, Karolinska Institute, Stockholm, Sweden. rhurme@pasteur.fr
Berndt
K D
KD
Normark
S J
SJ
Rhen
M
M
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004269:DNA, Bacterial / Q000378:metabolism; D006706:Homeostasis; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011487:Protein Conformation; D017510:Protein Folding; D012333:RNA, Messenger / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D012097:Repressor Proteins / Q000378:metabolism*; D012486:Salmonella typhimurium / Q000235:genetics / Q000502:physiology*; D013696:Temperature; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C075138:TlpA protein, Salmonella