Arabidopsis inositol polyphosphate kinase activities regulate COP9 deneddylation functions in phosphate homeostasis
Plant phosphate (Pi) homeostasis relies on coordinated activities of the inositol polyphosphate kinases IPK1 and ITPK1, which balance localized InsP₇ synthesis to control COP9 signalosome (CSN)–dependent deneddylation of cullin 1 (CUL1). Perturbation of this equilibrium affects the stability of SPX4, a key negative regulator of phosphate starvation response.
