3 research outputs found
Responses of <i>Pseudomonas putida</i> to Zinc Excess Determined at the Proteome Level: Pathways Dependent and Independent of ColRS
Zinc
is an important micronutrient for bacteria, but its excess is toxic.
Recently, the ColRS two-component system was shown to detect and respond
to zinc excess and to contribute to zinc tolerance of <i>Pseudomonas
putida</i>. Here, we applied a label-free whole-cell proteome
analysis to compare the zinc-induced responses of <i>P.Ā putida</i> and <i>colR</i> knockout. We identified dozens of proteins
that responded to zinc in a ColR-independent manner, among others,
known metal efflux systems CzcCBA1, CzcCBA2, CadA2 and CzcD. Nine
proteins were affected in a ColR-dependent manner, and besides known
ColR targets, four new candidates for ColR regulon were identified.
Despite the relatively modest ColR-dependent changes of wild-type, <i>colR</i> deficiency resulted in drastic proteome alterations,
with 122 proteins up- and 62 down-regulated by zinc. This zinc-promoted
response had remarkable overlap with the alternative sigma factor
AlgU-controlled regulon in <i>P.Ā aeruginosa</i>. The
most prominent hallmark was a high induction of alginate biosynthesis
proteins and regulators. This response likely alleviates the zinc
stress, as the AlgU-regulated alginate regulator AmrZ was shown to
contribute to zinc tolerance of <i>colR</i> knockout. Thus,
the ColRS system is important for zinc homeostasis, and in its absence,
alternative stress response pathways are activated to support the
zinc tolerance