Entry and exit from competence relies on stochastic gene expression induced by a circuit composed of ComK, ComS, and the protease complex MecA ClpP/C. (A) ComK is necessary and sufficient to induce competence in bacteria. The ComK protein is degraded by the MecA ClpP/C protease complex. ComK negatively regulates the expression of ComS, which, in turn, negatively regulates the protease complex by competing for binding with ComK. (B) The entire circuit cycles over time, resulting in changing levels of ComK, and cycling between competent and vegetative states. (C) The changes that occur over time to network components that result in entry into the competence state.
