Plays a negative role in salicylic acid (SA)-mediated resistance to powdery mildew (e.g. Golovinomyces cichoracearum). May modulate plant immunity by regulating the relocation of EDR1 by interacting with CHC2 and modulating endocytosis. Interacts with RLK902 (PubMed:15618630). Binds and recruits EDR1 at the powdery mildew (e.g. G.cichoracearum) penetration site on the plasma membrane. Interacts with CHC2 (PubMed:25747881). Displays dynamic movement in cells with accumulation at the plasma membrane around pathogenic fungus penetration site. Expressed in stems and rosette leaves, and weakly in inflorescences. Not detected in roots. Rapid but transient induction by wounding, salicylic acid treatment or pathogen infection (PubMed:15618630). Accumulates at the penetration site of powdery mildew (e.g. G.cichoracearum) infection (PubMed:25747881). Mild, hypersensitive response-like lesions under long-day conditions at late growth stages. Enhanced salicylic acid (SA) accumulation and SA signaling-dependent disease resistance to Golovinomyces cichoracearum UCSC1 associated with enhanced H(2)O(2) accumulation and callose deposition in the infection site as well as higher expression of defense-related genes (PRs). Reduced endocytosis rates.