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SJTU Researchers Revealed Molecular Mechanism of PDK1’s Role in Auxin Transport

May 14, 2020      Author: School of Agriculture and Biology

Recently, Xue Hongwei's research team from School of Agriculture and Biology, SJTU, and Jiří Friml's team from Institute of Science and Technology Austria published their research findings titled "The lipid code-dependent phosphoswitch PDK1-D6PK activates PIN-mediated auxin efflux in Arabidopsis" in Nature Plants online.

Dr. Tan Shutang is the first author of the paper, and Professor Xue Hongwei and Professor Jiří Friml are the corresponding authors. Also participating in the research are Professor Jan Petrášek of the Czech Academy of Sciences and his team, as well as researchers from University of Natural Resources and Life Sciences (BOKU). The research received funding from Chinese Ten-Thousand Talent Program and the European Union's Horizon2020 program (ERC grant agreement no. 742985). It was also funded by a European Molecular Biology Organization (EMBO) long-term postdoctoral fellowship (ALTF 723-2015) and a PhD scholarship from China Scholarship Council.

Abstract

Directional intercellular transport of the phytohormone auxin mediated by PIN-FORMED (PIN) efflux carriers has essential roles in both coordinating patterning processes and integrating multiple external cues by rapidly redirecting auxin fluxes. PIN activity is therefore regulated by multiple internal and external cues, for which the underlying molecular mechanisms are not fully elucidated. Here, we demonstrate that 3′-PHOSPHOINOSITIDE-DEPENDENT PROTEIN KINASE1 (PDK1), which is conserved in plants and mammals, functions as a molecular hub that perceives upstream lipid signalling and modulates downstream substrate activity through phosphorylation. Using genetic analysis, we show that the loss-of-function Arabidopsis pdk1.1 pdk1.2 mutant exhibits a plethora of abnormalities in organogenesis and growth due to defective polar auxin transport. Further cellular and biochemical analyses reveal that PDK1 phosphorylates D6 protein kinase, a well-known upstream activator of PIN proteins. We uncover a lipid-dependent phosphorylation cascade that connects membrane-composition-based cellular signalling with plant growth and patterning by regulating morphogenetic auxin fluxes.

 

Link: https://doi.org/10.1038/s41477-020-0648-9

 

 Translated  by Zhou Rong     Reviewed by Wang Bingyu