J Integr Plant Biol. ›› 2023, Vol. 65 ›› Issue (1): 82-99.DOI: 10.1111/jipb.13366

• Cell and Developmental Biology • Previous Articles     Next Articles

Transmembrane kinase 1-mediated auxin signal regulates membrane-associated clathrin in Arabidopsis roots

Yutong Wang1†, Xu Yan1†, Mei Xu1†, Weiyang Qi1, Chunjie Shi1, Xiaohong Li1, Jiaqi Ma1, Dan Tian1, Jianxin Shou1, Haijun Wu1, Jianwei Pan1, Bo Li1*, Chao Wang1,2*   

  1. 1. Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Sciences Lanzhou University Lanzhou 730000 China;
    2. College of Life Sciences Shaoxing University Shaoxing 312000 China
    These authors contributed equally to this article
    *Correspondences: Bo Li (li_bo@lzu.edu.cn); Chao Wang (wangc@lzu.edu.cn, Dr. Wang is fully responsible for the distribution of the materials associated with this article)
  • Received:2022-08-18 Accepted:2022-09-16 Online:2022-09-17 Published:2023-01-01

Abstract: Clathrin-mediated endocytosis (CME) is the major endocytic pathway in eukaryotic cells that directly regulates abundance of plasma membrane proteins. Clathrin triskelia are composed of clathrin heavy chains (CHCs) and light chains (CLCs), and the phytohormone auxin differentially regulates membrane-associated CLCs and CHCs, modulating the endocytosis and therefore the distribution of auxin efflux transporter PIN-FORMED2 (PIN2). However, the molecular mechanisms by which auxin regulates clathrin are still poorly understood. Transmembrane kinase (TMKs) family proteins are considered to contribute to auxin signaling and plant development; it remains unclear whether they are involved in PIN transport by CME. We assessed TMKs involvement in the regulation of clathrin by auxin, using genetic, pharmacological, and cytological approaches including live-cell imaging and immunofluorescence. In tmk1 mutant seedlings, auxin failed to rapidly regulate abundance of both CHC and CLC and to inhibit PIN2 endocytosis, leading to an impaired asymmetric distribution of PIN2 and therefore auxin. Furthermore, TMK3 and TMK4 were shown not to be involved in regulation of clathrin by auxin. In summary, TMK1 is essential for auxin-regulated clathrin recruitment and CME. TMK1 therefore plays a critical role in the establishment of an asymmetric distribution of PIN2 and an auxin gradient during root gravitropism.

Key words: Arabidopsis, auxin, clathrin, endocytosis, PIN2, transmembrane kinase1 (TMK1)

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