Member of the two-component regulatory system LiaS/LiaR probably involved in response to a subset of cell wall-active antibiotics that interfere with the lipid II cycle in the cytoplasmic membrane (bacitracin, nisin, ramoplanin and vancomycin). Seems also involved in response to cationic antimicrobial peptides and secretion stress. LiaR regulates the transcription of the liaIHGFSR operon. Autoregulated. Induced by antibiotics (vancomycin, bacitracin, nisin and ramoplanin), cationic antimicrobial peptides (human LL-37 and porcine PG-1), Triton X-100 and severe secretion stress. Phosphorylated by LiaS.