FIG. 1.
ComK-dependent and -independent MecA control of hag expression. High cell density and nutritional stress stimulate expression of the comS gene. ComS interaction with MecA-ClpC results in release of ComK, which activates comF-flgM operon transcription, as well as the expression of other late competence operons. Antisigma factor FlgM negatively controls ςD, resulting in reduced expression of hag and other genes of the ςD-regulon. MecA affects the ςD protein level, particularly in cells grown in medium that promotes competence development.