Confers resistance to Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). May form oligomers or be a component of larger protein complex in plasma membranes. Expressed in roots, young and senescing leaves, cauline leaves, stems and siliques. Accumulates upon infection with avirulent Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) carrying avirulence genes avrRpm1, avrRpt2, avrB, or avrRps4 but not with the virulent Pst DC3000 (Ref.1, PubMed:12059109). Induced by salicylic acid (SA). Accumulates rapidly in local and systemic tissues after wounding (PubMed:12059109). Triggered by spermine, an inducer of pathogenesis-related (PR) genes. Up-regulated by cucumber mosaic virus (CMV-Y and CMV-B2 strains) (PubMed:14666423). Glycosylated.