Involved in the regulation of cell death induced by extracellular reactive oxygen species (PubMed:19279211, PubMed:25398910). Only the processed peptide, and not the full length GRI can bind in vivo to the extracellular domain of the receptor PRK5 (PubMed:25398910). The GRIp-induced cell death is superoxide and salicylic acid dependent (PubMed:19279211). Interacts with PRK5 and to a lower extent with PRK4. Highly expressed in flowers, and at very low levels in leaves. Belongs to the STIG1 family.