title: Clathrin regulates blue light-triggered lateral auxin distribution and hypocotyl phototropism in Arabidopsis.
abstract: Phototropism is the process by which plants grow towards light in order to maximize the capture of light for photosynthesis, which is particularly important for germinating seedlings. In Arabidopsis, hypocotyl phototropism is predominantly triggered by blue light (BL), which has a profound effect on the establishment of asymmetric auxin distribution, essential for hypocotyl phototropism. Two auxin efflux transporters ATP-binding cassette B19 (ABCB19) and PIN-formed 3 (PIN3) are known to mediate the effect of BL on auxin distribution in the hypocotyl, but the details for how BL triggers PIN3 lateralization remain poorly understood. Here, we report a critical role for clathrin in BL-triggered, PIN3-mediated asymmetric auxin distribution in hypocotyl phototropism. We show that unilateral BL induces relocalization of clathrin in the hypocotyl. Loss of clathrin light chain 2 (CLC2) and CLC3 affects endocytosis and lateral distribution of PIN3 thereby impairing BL-triggered establishment of asymmetric auxin distribution and consequently, phototropic bending. Conversely, auxin efflux inhibitors N-1-naphthylphthalamic acid and 2,3,5-triiodobenzoic acid affect BL-induced relocalization of clathrin, endocytosis and lateralization of PIN3 as well as asymmetric distribution of auxin. These results together demonstrate an important interplay between auxin and clathrin function that dynamically regulates BL-triggered hypocotyl phototropism in Arabidopsis.
authors: College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China.
authors: Ying
authors: Y
authors: Zhang
authors: College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China.
authors: Qinqin
authors: Q
authors: Yu
authors: College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China.
authors: Nan
authors: N
authors: Jiang
authors: College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China.
authors: Xu
authors: X
authors: Yan
authors: College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China.
authors: Chao
authors: C
authors: Wang
authors: College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China.
authors: Qingmei
authors: Q
authors: Wang
authors: College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China.
authors: Jianzhong
authors: J
authors: Liu
authors: Institute of Genetics, Key Laboratory for Cell and Gene Engineering of Zhejiang Province, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
authors: Muyuan
authors: M
authors: Zhu
authors: Department of Biochemistry, University of Wisconsin - Madison, Madison, WI, 53706, USA.
authors: Sebastian Y
authors: SY
authors: Bednarek
authors: Department of Biological Sciences and NUS Centre for BioImaging Sciences, National University of Singapore, 14 Science Drive 4, 117543, Singapore.
authors: Jian
authors: J
authors: Xu
authors: College of Chemistry and Life Sciences, Zhejiang Normal University, Jinhua, 321004, China.
authors: Jianwei
authors: J
authors: Pan
mesh_terms: D017360:Arabidopsis / Q000502:physiology* / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000378:metabolism; D002966:Clathrin / Q000378:metabolism*; D004705:Endocytosis / Q000528:radiation effects; D018546:Hypocotyl / Q000502:physiology* / Q000528:radiation effects; D007210:Indoleacetic Acids / Q000378:metabolism*; D008027:Light; D018524:Phototropism / Q000528:radiation effects*
chemical_list: D029681:Arabidopsis Proteins; D002966:Clathrin; D007210:Indoleacetic Acids
keywords: PIN3 efflux transporter; asymmetric auxin distribution; endocytosis