Crosstalk between the serine/threonine kinase StkP and the response regulator ComE controls the stress response and intracellular survival of Streptococcus pneumoniae

PIÑAS GE; REINOSO-VIZCAINO NM; YANDAR BARAHONA NY; CORTES PR; ECHENIQUE JR

PLOS PATHOGENS

PUBLIC LIBRARY SCIENCE

Lugar: San Francisco; Año: 2018

1553-7366

treptococcus pneumoniae is an opportunistic human bacterial pathogen that usually colonizes the upper respiratory tract, but the invasion and survival mechanism in respiratory epithelial cells remains elusive. Previously, we described that acidic stress-induced lysis (ASIL) and intracellular survival are controlled by ComE through a yet unknown activation mechanism under acidic conditions, which is independent of the ComD histidine kinase that activates this response regulator for competence development at pH 7.8. Here, we demonstrate that the serine/threonine kinase StkP is essential for ASIL, and show that StkP phosphorylates ComE at Thr128. Molecular dynamic simulations predicted that Thr128-phosphorylation induces conformational changes on ComE?s DNA-binding domain. Using nonphosphorylatable (ComET128A) and phosphomimetic (ComET128E) proteins, we confirmed that Thr128-phosphorylation increased the DNA-binding affinity of ComE. The non-phosphorylated form of ComE interacted more st