This family consists of the Bacillus species specific PapR protein. The papR gene belongs to the PlcR regulon and is located 70 bp downstream from plcR. It encodes a 48-amino-acid peptide. Disruption of the papR gene abolishes expression of the PlcR regulon, resulting in a large decrease in haemolysis and virulence in insect larvae. A processed form of PapR activates the PlcR regulon by allowing PlcR to bind to its DNA target. This activating mechanism is strain specific.