Pneumococcal HtrA protease mediates inhibition of competence by the CiaRH two-component signaling system

M. E. Sebert, K. P. Patel, M. Plotnick, J. N. Weiser

Research output: Contribution to journalArticle

49 Citations (Scopus)

Abstract

Activation of the CiaRH two-component signaling system prevents the development of competence for genetic transformation in Streptococcus pneumoniae through a previously unknown mechanism. Earlier studies have shown that CiaRH controls the expression of htrA, which we show encodes a surface-expressed serine protease. We found that mutagenesis of the putative catalytic serine of HtrA, while not impacting the competence of a ciaRH+ strain, restored a normal competence profile to a strain having a mutation that constitutively activates the CiaH histidine kinase. This result implies that activity of HtrA is necessary for the CiaRH system to inhibit competence. Consistent with this finding, recombinant HtrA (rHtrA) decreased the competence of pneumococcal cultures. The rHtrA-mediated decline in transformation efficiency could not be corrected with excess competence-stimulating peptide (CSP), suggesting that HtrA does not act through degradation of this signaling molecule. The inhibitory effects of rHtrA and activated CiaH, however, were largely overcome in a strain having constitutive activation of the competence pathway through a mutation in the cytoplasmic domain of the ComD histidine kinase. Although these results suggested that HtrA might act through degradation of the extracellular portion of the ComD receptor, Western immunoblots for ComD did not reveal changes in protein levels attributable to HtrA. We therefore postulate that HtrA may act on an unknown protein target that potentiates the activation of the ComDE system by CSP. These findings suggest a novel regulatory role for pneumococcal HtrA in modulating the activity of a two-component signaling system that controls the development of genetic competence.

Original languageEnglish (US)
Pages (from-to)3969-3979
Number of pages11
JournalJournal of Bacteriology
Volume187
Issue number12
DOIs
StatePublished - Jun 2005

Fingerprint

Mental Competency
Peptide Hydrolases
Genetic Transformation
Inhibition (Psychology)
Peptides
Mutation
Serine Proteases
Streptococcus pneumoniae
Mutagenesis
Serine
Proteins
Western Blotting
Efficiency

ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Immunology

Cite this

Pneumococcal HtrA protease mediates inhibition of competence by the CiaRH two-component signaling system. / Sebert, M. E.; Patel, K. P.; Plotnick, M.; Weiser, J. N.

In: Journal of Bacteriology, Vol. 187, No. 12, 06.2005, p. 3969-3979.

Research output: Contribution to journalArticle

Sebert, M. E. ; Patel, K. P. ; Plotnick, M. ; Weiser, J. N. / Pneumococcal HtrA protease mediates inhibition of competence by the CiaRH two-component signaling system. In: Journal of Bacteriology. 2005 ; Vol. 187, No. 12. pp. 3969-3979.
@article{28b5b229b4cb4929822bf996ebeac618,
title = "Pneumococcal HtrA protease mediates inhibition of competence by the CiaRH two-component signaling system",
abstract = "Activation of the CiaRH two-component signaling system prevents the development of competence for genetic transformation in Streptococcus pneumoniae through a previously unknown mechanism. Earlier studies have shown that CiaRH controls the expression of htrA, which we show encodes a surface-expressed serine protease. We found that mutagenesis of the putative catalytic serine of HtrA, while not impacting the competence of a ciaRH+ strain, restored a normal competence profile to a strain having a mutation that constitutively activates the CiaH histidine kinase. This result implies that activity of HtrA is necessary for the CiaRH system to inhibit competence. Consistent with this finding, recombinant HtrA (rHtrA) decreased the competence of pneumococcal cultures. The rHtrA-mediated decline in transformation efficiency could not be corrected with excess competence-stimulating peptide (CSP), suggesting that HtrA does not act through degradation of this signaling molecule. The inhibitory effects of rHtrA and activated CiaH, however, were largely overcome in a strain having constitutive activation of the competence pathway through a mutation in the cytoplasmic domain of the ComD histidine kinase. Although these results suggested that HtrA might act through degradation of the extracellular portion of the ComD receptor, Western immunoblots for ComD did not reveal changes in protein levels attributable to HtrA. We therefore postulate that HtrA may act on an unknown protein target that potentiates the activation of the ComDE system by CSP. These findings suggest a novel regulatory role for pneumococcal HtrA in modulating the activity of a two-component signaling system that controls the development of genetic competence.",
author = "Sebert, {M. E.} and Patel, {K. P.} and M. Plotnick and Weiser, {J. N.}",
year = "2005",
month = "6",
doi = "10.1128/JB.187.12.3969-3979.2005",
language = "English (US)",
volume = "187",
pages = "3969--3979",
journal = "Journal of Bacteriology",
issn = "0021-9193",
publisher = "American Society for Microbiology",
number = "12",

}

TY - JOUR

T1 - Pneumococcal HtrA protease mediates inhibition of competence by the CiaRH two-component signaling system

AU - Sebert, M. E.

AU - Patel, K. P.

AU - Plotnick, M.

AU - Weiser, J. N.

PY - 2005/6

Y1 - 2005/6

N2 - Activation of the CiaRH two-component signaling system prevents the development of competence for genetic transformation in Streptococcus pneumoniae through a previously unknown mechanism. Earlier studies have shown that CiaRH controls the expression of htrA, which we show encodes a surface-expressed serine protease. We found that mutagenesis of the putative catalytic serine of HtrA, while not impacting the competence of a ciaRH+ strain, restored a normal competence profile to a strain having a mutation that constitutively activates the CiaH histidine kinase. This result implies that activity of HtrA is necessary for the CiaRH system to inhibit competence. Consistent with this finding, recombinant HtrA (rHtrA) decreased the competence of pneumococcal cultures. The rHtrA-mediated decline in transformation efficiency could not be corrected with excess competence-stimulating peptide (CSP), suggesting that HtrA does not act through degradation of this signaling molecule. The inhibitory effects of rHtrA and activated CiaH, however, were largely overcome in a strain having constitutive activation of the competence pathway through a mutation in the cytoplasmic domain of the ComD histidine kinase. Although these results suggested that HtrA might act through degradation of the extracellular portion of the ComD receptor, Western immunoblots for ComD did not reveal changes in protein levels attributable to HtrA. We therefore postulate that HtrA may act on an unknown protein target that potentiates the activation of the ComDE system by CSP. These findings suggest a novel regulatory role for pneumococcal HtrA in modulating the activity of a two-component signaling system that controls the development of genetic competence.

AB - Activation of the CiaRH two-component signaling system prevents the development of competence for genetic transformation in Streptococcus pneumoniae through a previously unknown mechanism. Earlier studies have shown that CiaRH controls the expression of htrA, which we show encodes a surface-expressed serine protease. We found that mutagenesis of the putative catalytic serine of HtrA, while not impacting the competence of a ciaRH+ strain, restored a normal competence profile to a strain having a mutation that constitutively activates the CiaH histidine kinase. This result implies that activity of HtrA is necessary for the CiaRH system to inhibit competence. Consistent with this finding, recombinant HtrA (rHtrA) decreased the competence of pneumococcal cultures. The rHtrA-mediated decline in transformation efficiency could not be corrected with excess competence-stimulating peptide (CSP), suggesting that HtrA does not act through degradation of this signaling molecule. The inhibitory effects of rHtrA and activated CiaH, however, were largely overcome in a strain having constitutive activation of the competence pathway through a mutation in the cytoplasmic domain of the ComD histidine kinase. Although these results suggested that HtrA might act through degradation of the extracellular portion of the ComD receptor, Western immunoblots for ComD did not reveal changes in protein levels attributable to HtrA. We therefore postulate that HtrA may act on an unknown protein target that potentiates the activation of the ComDE system by CSP. These findings suggest a novel regulatory role for pneumococcal HtrA in modulating the activity of a two-component signaling system that controls the development of genetic competence.

UR - http://www.scopus.com/inward/record.url?scp=20444479106&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=20444479106&partnerID=8YFLogxK

U2 - 10.1128/JB.187.12.3969-3979.2005

DO - 10.1128/JB.187.12.3969-3979.2005

M3 - Article

C2 - 15937159

AN - SCOPUS:20444479106

VL - 187

SP - 3969

EP - 3979

JO - Journal of Bacteriology

JF - Journal of Bacteriology

SN - 0021-9193

IS - 12

ER -