The rice CK2 kinase regulates trafficking of phosphate transporters in response to phosphate levels.
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, CK2β3, 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 CK2β3 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 CK2α3/β3 negatively regulates PTs and phosphorus status regulates CK2α3/β3.
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Jieyu
J
Chen
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Yifeng
Y
Wang
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Fei
F
Wang
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Jian
J
Yang
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Mingxing
M
Gao
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Changying
C
Li
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Yingyao
Y
Liu
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Yu
Y
Liu
Institute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, Japan.
Naoki
N
Yamaji
Institute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, Japan.
Jian Feng
JF
Ma
Centro Nacional de Biotecnologia, Consejo Superior de Investigaciones Científicas, Campus de Cantoblanco, 28049 Madrid, Spain.
Javier
J
Paz-Ares
Unité Mixte de Recherche 7265 Commissariat à l'Energie Atomique/CNRS/University of Aix-Marseille, Institute for Biotechnology and Environmental Biology/SBVME/Laboratory of Plant Development Biology, Commissariat à l'Energie Atomique, Cadarache, St. Paul lez Durance F-13108, France.
Laurent
L
Nussaume
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Shuqun
S
Zhang
State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China Key Laboratory of Plant Nutrition and Fertilizer, Ministry of Agriculture, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Keke
K
Yi
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China wzchang@zju.edu.cn.
Zhongchang
http://orcid.org/0000-0001-6383-3817
Z
Wu
State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China.
Ping
P
Wu
D047390:Casein Kinase II / Q000378:metabolism*; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000187:drug effects / Q000201:enzymology*; D010641:Phenotype; D028061:Phosphate Transport Proteins / Q000378:metabolism*; D010710:Phosphates / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D010940:Plant Proteins / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D012694:Serine / Q000378:metabolism
D028061:Phosphate Transport Proteins; D010710:Phosphates; D010940:Plant Proteins; D012694:Serine; D047390:Casein Kinase II