The protein tyrosine kinases EpsB and PtkA differentially affect biofilm formation in Bacillus subtilis.
The Gram-positive soil bacterium Bacillus subtilis is able to choose between motile and sessile lifestyles. The sessile way of life, also referred to as biofilm, depends on the formation of an extracellular polysaccharide matrix and some extracellular proteins. Moreover, a significant proportion of cells in a biofilm form spores. The first two genes of the 15-gene operon for extracellular polysaccharide synthesis, epsA and epsB, encode a putative transmembrane modulator protein and a putative protein tyrosine kinase, respectively, with similarity to the TkmA/PtkA modulator/kinase couple. Here we show that the putative kinase EpsB is required for the formation of structured biofilms. However, an epsB mutant is still able to form biofilms. As shown previously, a ptkA mutant is also partially defective in biofilm formation, but this defect is related to spore formation in the biofilm. The absence of both kinases resulted in a complete loss of biofilm formation. Thus, EpsB and PtkA fulfil complementary functions in biofilm formation. The activity of bacterial protein tyrosine kinases depends on their interaction with modulator proteins. Our results demonstrate the specific interaction between the putative kinase EpsB and its modulator protein EpsA and suggest that EpsB activity is stimulated by its modulator EpsA.
Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August University Göttingen, Grisebachstr. 8, D-37077 Göttingen, Germany.
Jan
J
Gerwig
Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
Taryn B
TB
Kiley
Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August University Göttingen, Grisebachstr. 8, D-37077 Göttingen, Germany.
Katrin
K
Gunka
Division of Molecular Microbiology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
Nicola
N
Stanley-Wall
Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August University Göttingen, Grisebachstr. 8, D-37077 Göttingen, Germany.
Jörg
J
Stülke
D001412:Bacillus subtilis / Q000201:enzymology* / Q000235:genetics / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D017353:Gene Deletion; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*
D011505:Protein-Tyrosine Kinases