biostudies-literatureGuan ZEuropean Research Council1581https://www.ebi.ac.uk/biostudies/studies/S-EPMC8948245biostudies-literatureUnknown13(1)Phosphate (Pi) starvation response (PHR) transcription factors play key roles in plant Pi homeostasis maintenance. They are negatively regulated by stand-alone SPX proteins, cellular receptors for inositol pyrophosphate (PP-InsP) nutrient messengers. How PP-InsP-bound SPX interacts with PHRs is poorly understood. Here, we report crystal structures of the rice SPX2/InsP₆/PHR2 complex and of the PHR2 DNA binding (MYB) domain in complex with target DNA at resolutions of 3.1 Å and 2.7 Å, respectively. In the SPX2/InsP₆/PHR2 complex, the signalling-active SPX2 assembles into a domain-swapped dimer conformation and binds two copies of PHR2, targeting both its coiled-coil (CC) oligomerisation domain and MYB domain. Our results reveal that the SPX2 senses PP-InsPs to inactivaNature communicationsMechanistic insights into the regulation of plant phosphate homeostasis by the rice SPX2 - PHR2 complex.PMC8948245818696Zhang DYan JHothorn MChen JPei KLiu RZhang QLiu ZGuan ZWang QZhang ZZuo JCheng PSavarin JBroger LYin PZou TfalseMechanistic insights into the regulation of plant phosphate homeostasis by the rice SPX2 - PHR2 complex.Phosphate (Pi) starvation response (PHR) transcription factors play key roles in plant Pi homeostasis maintenance. They are negatively regulated by stand-alone SPX proteins, cellular receptors for inositol pyrophosphate (PP-InsP) nutrient messengers. How PP-InsP-bound SPX interacts with PHRs is poorly understood. Here, we report crystal structures of the rice SPX2/InsP₆/PHR2 complex and of the PHR2 DNA binding (MYB) domain in complex with target DNA at resolutions of 3.1 Å and 2.7 Å, respectively. In the SPX2/InsP₆/PHR2 complex, the signalling-active SPX2 assembles into a domain-swapped dimer conformation and binds two copies of PHR2, targeting both its coiled-coil (CC) oligomerisation domain and MYB domain. Our results reveal that the SPX2 senses PP-InsPs to inactiva2022-01-01T00:00:00Z2022 Mar2026-06-01T03:05:40.285Z2024-11-20T08:53:25.779ZS-EPMC89482453533215510.1038/s41467-022-29275-8