7E40

Mechanism of Phosphate Sensing and Signaling Revealed by Rice SPX1-PHR2 Complex Structure

Summary for 7E40

• Entry DOI: 10.2210/pdb7e40/pdb
• Descriptor: Protein PHOSPHATE STARVATION RESPONSE 2, SPX domain-containing protein 1,Endolysin, INOSITOL HEXAKISPHOSPHATE, ... (4 entities in total)
• Functional Keywords: phosphate sensing and responding, insp6-osspx1-osphr2 ternary complex, allosterically regulation, dna binding inhibition, plant protein, protein binding
• Biological source: Oryza sativa subsp. japonica (Rice); More
• Total number of polymer chains: 4
• Total formula weight: 114746.04

Authors

Zhou, J.,Hu, Q.,Yao, D.,Xing, W. (deposition date: 2021-02-09, release date: 2021-11-10, Last modification date: 2024-05-29)

Primary citation

Zhou, J.,Hu, Q.,Xiao, X.,Yao, D.,Ge, S.,Ye, J.,Li, H.,Cai, R.,Liu, R.,Meng, F.,Wang, C.,Zhu, J.K.,Lei, M.,Xing, W.
Mechanism of phosphate sensing and signaling revealed by rice SPX1-PHR2 complex structure.
Nat Commun, 12:7040-7040, 2021

PubMed Abstract: Phosphate, a key plant nutrient, is perceived through inositol polyphosphates (InsPs) by SPX domain-containing proteins. SPX1 an inhibit the PHR2 transcription factor to maintain Pi homeostasis. How SPX1 recognizes an InsP molecule and represses transcription activation by PHR2 remains unclear. Here we show that, upon binding InsP, SPX1 can disrupt PHR2 dimers and form a 1:1 SPX1-PHR2 complex. The complex structure reveals that SPX1 helix α1 can impose a steric hindrance when interacting with the PHR2 dimer. By stabilizing helix α1, InsP allosterically decouples the PHR2 dimer and stabilizes the SPX1-PHR2 interaction. In doing so, InsP further allows SPX1 to engage with the PHR2 MYB domain and sterically block its interaction with DNA. Taken together, our results suggest that, upon sensing the surrogate signals of phosphate, SPX1 inhibits PHR2 via a dual mechanism that attenuates dimerization and DNA binding activities of PHR2.

PubMed: 34857773
DOI: 10.1038/s41467-021-27391-5

Experimental method

X-RAY DIFFRACTION (2.6 Å)