Bacillus subtilis BY-kinase PtkA controls enzyme activity and localization of its protein substrates.
Bacillus subtilis BY-kinase PtkA was previously shown to phosphorylate, and thereby regulate the activity of two classes of protein substrates: UDP-glucose dehydrogenases and single-stranded DNA-binding proteins. Our recent phosphoproteome study identified nine new tyrosine-phosphorylated proteins in B. subtilis. We found that the majority of these proteins could be phosphorylated by PtkA in vitro. Among these new substrates, single-stranded DNA exonuclease YorK, and aspartate semialdehyde dehydrogenase Asd were activated by PtkA-dependent phosphorylation. Because enzyme activity was not affected in other cases, we used fluorescent protein tags to study the impact of PtkA on localization of these proteins in vivo. For several substrates colocalization with PtkA was observed, and more importantly, the localization pattern of the proteins enolase, YjoA, YnfE, YvyG, Ugd and SsbA was dramatically altered in DeltaptkA background. Our results confirm that PtkA can control enzyme activity of its substrates in some cases, but also reveal a new mode of action for PtkA, namely ensuring correct cellular localization of its targets.
Jers
Carsten
C
Micalis UMR 1319, AgroParisTech-INRA, Jouy-en-Josas, France.
Pedersen
Malene Mejer
MM
Paspaliari
Dafni Katerina
DK
Schütz
Wolfgang
W
Johnsson
Christina
C
Soufi
Boumediene
B
Macek
Boris
B
Jensen
Peter Ruhdal
PR
Mijakovic
Ivan
I
D001412:Bacillus subtilis / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity
D001426:Bacterial Proteins; D011505:Protein-Tyrosine Kinases