HtrA is a key factor in the response to specific stress conditions in Lactococcus lactis.
We investigated the physiological role of Lactococcus lactis housekeeping surface protease HtrA. It is involved in surface properties under regular growth conditions, as the htrA mutant strain forms longer chains in liquid medium. It participates in cellular defence against environmental stress conditions: compared to the wild-type strain, the htrA mutant strain exhibited increased sensitivity to heat, ethanol, puromycin, and NaCl, but not to pH, H2O2, bile salts or to carbon or nitrogen starvation. htrA transcription in the wild-type strain showed a transient increase under stress conditions determined as requiring htrA, but not under overexpression of a secreted heterologous protein. Our results demonstrate that in L. lactis, htrA is a key factor in the response to specific stress conditions.
Foucaud-Scheunemann
Catherine
C
INRA, Unité de Recherches Laitières et Génétique Appliquée, 78352 Jouy en Josas, France. foucaud@jouy.inra.fr
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D000900:Anti-Bacterial Agents / Q000494:pharmacology; D000891:Anti-Infective Agents, Local / Q000494:pharmacology; D024881:Drug Resistance, Bacterial; D000431:Ethanol / Q000494:pharmacology; D006360:Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D018869:Heat-Shock Response / Q000502:physiology*; D006358:Hot Temperature; D013294:Lactococcus lactis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D033903:Periplasmic Proteins / Q000235:genetics / Q000378:metabolism*; D011691:Puromycin / Q000494:pharmacology; D012333:RNA, Messenger; D012697:Serine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology; D014158:Transcription, Genetic
D000900:Anti-Bacterial Agents; D000891:Anti-Infective Agents, Local; D006360:Heat-Shock Proteins; D033903:Periplasmic Proteins; D012333:RNA, Messenger; D000431:Ethanol; D012965:Sodium Chloride; D011691:Puromycin; C061682:DegP protease; D012697:Serine Endopeptidases