Premium
Identification of EloR (Spr1851) as a regulator of cell elongation in Streptococcus pneumoniae
Author(s) -
Stamsås Gro Anita,
Straume Daniel,
Ruud Winther Anja,
Kjos Morten,
Frantzen Cyril Alexander,
Håvarstein Leiv Sigve
Publication year - 2017
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.13748
Subject(s) - biology , phosphorylation , microbiology and biotechnology , dephosphorylation , cell growth , biochemistry , phosphatase
Summary In a screen for mutations suppressing the lethal loss of PBP2b in Streptococcus pneumoniae we identified Spr1851 (named EloR), a cytoplasmic protein of unknown function whose inactivation removed the requirement for PBP2b as well as RodA. It follows from this that EloR and the two elongasome proteins must be part of the same functional network. This network also includes StkP, as this serine/threonine kinase phosphorylates EloR on threonine 89 (T89). We found that Δ eloR cells, and cells expressing the phosphoablative form of EloR (EloR T89A ), are significantly shorter than wild‐type cells. Furthermore, the phosphomimetic form of EloR (EloR T89E ) is not tolerated unless the cell in addition acquires a truncated MreC or non‐functional RodZ protein. By itself, truncation of MreC as well as inactivation of RodZ gives rise to less elongated cells, demonstrating that the stress exerted by the phosphomimetic form of EloR is relieved by suppressor mutations that reduce or abolish the activity of the elongasome. Of note, it was also found that loss of elongasome activity caused by truncation of MreC elicits increased StkP‐mediated phosphorylation of EloR. Together, the results support a model in which phosphorylation of EloR stimulates cell elongation, while dephosphorylation has an inhibitory effect.