BrgE is a regulator of Myxococcus xanthus development.
We report here the identification and characterization of a member of the Myxococcus xanthus SdeK signal transduction pathway, BrgE. This protein was identified as an SdeK-interacting component using a yeast two-hybrid screen, and we further confirmed this interaction by the glutathione S-transferase (GST) pulldown assay. Additional yeast two-hybrid analyses revealed that BrgE preferentially interacts with the putative amino-terminal sensor domain of SdeK, but not with the carboxy-terminal kinase domain. A brgE insertion strain was shown to be blocked in development between aggregation and mound formation, and decreased by 50-fold in viable spore production compared with the parental wild type. These phenotypes are similar to those of sdeK mutants. The brgE mutation also altered expression of a sample of Tn5 lac developmental markers that are also SdeK regulated. Finally, we demonstrated that a brgE sdeK double mutant has a more severe sporulation defect than either of the two single mutants, suggesting that BrgE and SdeK act synergistically to regulate wild-type levels of sporulation. In sum, these data suggest that BrgE operates as an auxiliary factor to stimulate the SdeK signal transduction pathway by directly binding to the amino-terminal sensor domain of SdeK.
Pham
Vinh D
VD
Section of Microbiology and Center for Genetics and Development, University of California, Davis, CA 95616, USA.
Shebelut
Conrad W
CW
Zumstein
Erin J
EJ
Singer
Mitchell
M
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D016941:Myxococcus xanthus / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000502:physiology; D015398:Signal Transduction; D013171:Spores, Bacterial / Q000254:growth & development; D020798:Two-Hybrid System Techniques
D001426:Bacterial Proteins; D003470:Culture Media; C114349:SdeK protein, Myxococcus xanthus