The rice CK2 kinase regulates trafficking of phosphate transporters in response to phosphate levels

Jieyu Chen, Yifeng Wang, Fei Wang, Jian Yang, Mingxing Gao, Changying Li, Yingyao Liu, Yu Liu, Naoki Yamaji, Jian Feng Ma, Javier Paz-Ares, Laurent Nussaume, Shuqun Zhang, Keke Yi, Zhongchang Wu, Ping Wu

Research output: Contribution to journalArticlepeer-review

95 Citations (Scopus)


Phosphate transporters (PTs) mediate phosphorus uptake and are regulated at the transcriptional and posttranslational levels. In one key mechanism of posttranslational regulation, phosphorylation of PTs affects their trafficking from the endoplasmic reticulum (ER) to the plasma membrane. However, the kinase(s) mediating PT phosphorylation and the mechanism leading to ER retention of phosphorylated PTs remain unclear. In this study, we identified a rice (Oryza sativa) kinase subunit, CK2α3, which interacts with PT2 and PT8 in a yeast two-hybrid screen. Also, the CK2α3/β3 holoenzyme phosphorylates PT8 under phosphate-sufficient conditions. This phosphorylation inhibited the interaction of PT8 with PHOSPHATE TRANSPORTER TRAFFIC FACILITATOR1, a key cofactor regulating the exit of PTs from the ER to the plasma membrane. Additionally, phosphorus starvation promoted CK2α3 degradation, relieving the negative regulation of PT phosphorus-insufficient conditions. In accordance, transgenic expression of a nonphosphorylatable version of OsPT8 resulted in elevated levels of that protein at the plasma membrane and enhanced phosphorus accumulation and plant growth under various phosphorus regimes. Taken together, these results indicate that CK2a3/b3 negatively regulates PTs and phosphorus status regulates CK2α3/β3.

Original languageEnglish
Pages (from-to)711-723
Number of pages13
JournalPlant Cell
Issue number3
Publication statusPublished - 2015

ASJC Scopus subject areas

  • Plant Science
  • Cell Biology


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