In budding yeasts, Npr3 forms a complex with NPR2. This complex heterodimer is responsible for inactivating TORC1, an evolutionarily conserved protein complex that controls cell size via nutritional input signals, specifically, in response to amino acid starvation []. In fission yeast, Nitrogen permease regulator 3-like protein (part of GATOR complex) is dispensable for TORC1 regulation under amino acid starvation and thus, responds to nitrogen starvation [].In humans, Npr3 like protein, NPRL3, is part of the GATOR1 complex that functions as an inhibitor of the amino acid-sensing branch of the TORC1 pathway [].
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 [, ].
