Congresos y reuniones científicas
Título:
The acidic stress-induced lysis is mediated by STKP and CIARH in Streptococcus pneumoniae
Autor/es:
PIÑAS GE., ALBARRACÍN ORIO A., CORTES, P., Y ECHENIQUE, J
Reunión:
Encuentro; XLIII REUNION ANUAL SOCIEDAD ARGENTINA DE INVESTIGACION EN BIOQUIMICA Y BIOLOGIA MOLECULAR; 2007
Institución organizadora:
SAIB
Resumen:
We have described that acidic stress triggers autolysis in
and that this process is mediated by the response
regulator ComE, through a quorum sensing (QS) independent
pathway. This constitutes a novel function of ComE, since it has
been implicated in the regulation of competence development at
alkaline pH, through a QS mechanism. In the present work, we
studied the contribution of CiaRH two-component system and the
StkP serine/threonine kinase in the acidic stress-induced lysis
(ASIL), since they can regulate the comCDE operon and are
involved in resistance to several types of stress and lytic conditions.
We observed that ciaR and ciaH mutants lysed more rapidly than
wild type strain (wt). Double ciaR/comE or ciaH/comE mutants
were as susceptible to ASIL as the ciaR or ciaH mutants, indicating
that CiaRH protects cells from ASIL by a ComE-independent
pathway. Analysis of the stkP mutant showed that ASIL was
blocked, and a similar phenotype was observed in stkP/ciaR or
stkP/ciaH mutants. To investigate whether StkP was involved in the
ComE-mediatedASILpathway, we constructed a stkP/cup3 mutant,
since strain cup3 has high levels of comE transcripts and shows
accelerated lysis. Interestingly, ASIL was also abolished in the
stkP/cup3 mutant. We conclude that StkP is necessary for the
induction of ASIL by participating in both ComE and CiaRH
regulatory pathways.