Suggested to be the precursor for an exported, modified peptide that has antimicrobial and/or signaling properties. Synthesis requires YydG and YydH; the peptide is proposed to be exported by the YydIJ transporter. In the absence of the transporter, the modified peptide activates the LiaRS two-component regulatory system, possibly by eliciting cell envelope stress. This activation can occur in trans in cocultured cells lacking either the transporter or the whole operon. Repressed by AbrB. Induced in stationary phase in LB (rich) medium; the transcript is present in log phase cells grown in modified competence (MC) and MM media.