Signal transduction and sporulation in Bacillus subtilis : autophosphorylation of SpoOA, a sporulation initiation gene product

SpoOA is a positive/negative transcriptional regulator that plays a very important role in sporulation initiation in Bacillus subtilis. The N-terminal amino acid sequence of SpoOA is homologous to that of regulator proteins of the two-component regulatory systems involved in signal transduction in bacteria. Phosphorylation of SpooA through a phosphorelay has been reported recently. In this study, we found that SpoOA is autophosphorylated in the presence of ATP and that an autophosphorylation-deficient SpoOA mutant is completely defective in initiating sporulation. These results suggest that SpoOA autophosphorylation is an essential event in the signal transduction process that controls sporulation in B. subtilis.