The stability of cytadherence proteins in Mycoplasma pneumoniae requires activity of the protein kinase PrkC.
Mycoplasma pneumoniae belongs to the mollicutes, a group of bacteria that have strongly reduced genomes but that are nevertheless capable of independent life. With only three transcription factors, the regulatory features of these bacteria are very limited. Thus, posttranslational regulation might be important for M. pneumoniae. In addition to the highly specific HPr kinase, the M. pneumoniae prkC gene encodes the serine/threonine protein kinase C. In order to study the function(s) of this kinase, we isolated an M. pneumoniae mutant affected in PrkC. This mutation resulted in nonadherent growth and loss of cytotoxicity. Examination of the phosphorylation profile of the prkC mutant suggested that phosphorylation of cytadherence proteins was affected by the loss of this kinase. In contrast, inactivation of the prpC gene affecting the protein phosphatase that antagonizes PrkC-dependent phosphorylation resulted in more intensive phosphorylation of the cytadherence proteins HMW1 and HMW3 of the major adhesin P1 and of the surface protein MPN474. Moreover, loss of PrkC affects not only the phosphorylation state of the cytadherence proteins but also their intracellular accumulation. However, the expression of the corresponding genes was not affected by PrkC, suggesting that PrkC-dependent phosphorylation results in stabilization of the cytadherence proteins. The HMW proteins and P1 are part of the so-called terminal organelle of M. pneumoniae that is involved in gliding motility, cell division, and adhesion to host epithelial tissues. Our observations suggest that the posttranslational modification of cytadherence proteins by PrkC is essential for the development and function of the M. pneumoniae terminal organelle.
Department of General Microbiology, Institute of Microbiology and Genetics, Georg-August University Göttingen, Grisebachstr. 8, 37077 Göttingen, Germany.
Sebastian R
SR
Schmidl
Katrin
K
Gronau
Claudine
C
Hames
Julia
J
Busse
Dörte
D
Becher
Michael
M
Hecker
Jörg
J
Stülke
D001422:Bacterial Adhesion / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D006367:HeLa Cells; D006801:Humans; D009154:Mutation; D009177:Mycoplasma pneumoniae / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases; D040901:Proteomics; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D011494:Protein Kinases