Plays a role in resistance against cationic antimicrobial peptides (CAMPs) (PubMed:25685323, PubMed:21765893). Facilitates the activation of GraS to transduce the signal to GraR (PubMed:25685323). Homodimer (PubMed:25685323). Interacts with GraR and GraS (PubMed:25685323).