This domain can be found in the plant NPR proteins. Arabidopsis NPR1 is a key regulator of the salicylic acid (SA)-mediated systemic acquired resistance (SAR) pathway []. Its paralogs, NPR3, and NPR4, bind SA and control the proteasome-mediated degradation of NPR1 through their interaction with NPR1 [].
NIMIN1/3 are linked to the salicylic acid-dependent systemic acquired resistance response (SAR), a plant immune response []. They interact via a motif at the C terminus with the regulatory protein NPR1 (also known as NIM1), a key regulator of SAR in Arabidopsis [].NH1 is the rice orthologueof NPR1, and NRR has been identified as an NH1 and NPR1 interactor []. NH1 is a transcriptional co-activator that represses NH1-mediated activation. NRR homologues 1, 2 and 3 (RH1, RH2, and RH3) have also been reported to bind to, and repress to varying degrees, NH1-mediated transcriptional activation []. RH1 and RH3, but not RH2, also effectively repress NH1-mediated transcriptional activation [].
This entry represents a group of plant regulatory proteins, including NPR1-4 from Arabidopsis. NPR1 is a central regulator of salicylic-acid (SA)-mediated defense signaling in Arabidopsis. It contains a BTB/POZ domain at the N-terminal and an ankyrin-repeat domain in the central region. It binds to TGA1, a member of the TGA family of transcription factors that activate SA-responsive elements in the promoters of PR (PATHOGENESIS-RELATED) genes. It also has cytosolic function in cross-communication between SA- and JA-dependent defense signaling pathways []. NPR1 is functionally conserved in diverse plant species, including rice (Oryza sativa L.) []. NPR3 and NPR4 have also been shown to be required for basal defense against pathogens [, ].
NIMIN-1 is a member of a novel family of proteins from Arabidopsis (also consisting of NIMIN-2 and NIMIN-3) that interact with NPR1/NIM1, a key regulator of systemic acquired resistance in plants []. NIMIN1 interaction with NPR1 modulates pathogenesis-related gene expression [].
