Negative as well as positive regulator of alternate developmental processes that are induced at the end of vegetative growth in response to nutrient depletion. Binds to the alkaline protease (aprE) gene at two sites. Also acts as a repressor of the key sporulation gene spo0A. Negatively regulates transcription of the eps operon, which is responsible for the biosynthesis of an exopolysaccharide involved in biofilm formation; therefore it could govern the transition between a state in which bacteria swim or swarm and a state in which bacteria assemble into multicellular communities. Acts with Hpr as a corepressor of epr expression. Also negatively regulates transcription of the lutABC operon, which is required for lactate utilization. Repressor activity is regulated by SinI. Homotetramer in the absence of SinI. Heterodimer with SinI. Interaction with SinI disrupts the SinR tetramer and its repressor activity. Interacts with hpr.