Enhanced disease susceptibility 1 protein EP domain
The plant specific protein family, which comprises EDS1 (Enhanced disease susceptibility 1), PAD4 (Phytoalexin deficient4) and SAG101 (Senescence-associated gene 101), is involved in innate immunity [Ref.1]. Signaling by intracellular immune receptor ...
The plant specific protein family, which comprises EDS1 (Enhanced disease susceptibility 1), PAD4 (Phytoalexin deficient4) and SAG101 (Senescence-associated gene 101), is involved in innate immunity [Ref.1]. Signaling by intracellular immune receptors with NB-ARC domain (Pfam:PF00931) relies on this protein family [1,3]. C-terminus of Arabidopsis EDS1 and PAD4 proteins did not have recognizable sequence homology to other domains and therefore named EP domain (EDS1-PAD4) [2]. A combination of an N-terminal lipase_3 domain (Pfam:PF01764) and the C-terminal EP-domain is the defining feature of this family. Structurally, EP domain comprises exclusively of alpha-helices (PDB:4NFU) [1]. Structure-function analysis of Arabidopsis proteins showed that EDS1 forms heterodimers with PAD4 or SAG101, chiefly through the N-terminal lipase_3 domain. These heterodimers are essential for plant defense signaling. The EP domain is not stable without the lipase_3 domain, but is required for immunity [1]. Mutations of conserved residues in the EP domain of EDS1 strongly affect its immune signaling function [4].
