Under high cellular Pi conditions, SPX1 and SPX2 interact wi...

created [InstanceEdit:9031336] Gupta, Parul, 2017-11-29
dbId 9031086
displayName Under high cellular Pi conditions, SPX1 and SPX2 interact wi...
schemaClass Summation
text Under high cellular Pi conditions, SPX1 and SPX2 interact with PHR2 with high binding affinity in the nucleus and prevent PHR2 from binding to the P1BS motif in the promoters of PSI genes. Thus, the transcription levels of PSI genes, including SPX1 and SPX2, are basal. However, under low cellular Pi conditions, interaction of SPX1 and SPX2 with PHR2 is weaken and the P1BS motif of PSI genes competes with SPX1 and SPX2 to interact with PHR2, allowing PHR2 to up-regulate PSI genes, including SPX1 and SPX2. In turn, the accumulation of SPX1 and SPX2 under Pi-deficient conditions allows plants to shut down the PHR2-dependent Pi starvation response rapidly after Pi repletion.