title: Augmin triggers microtubule-dependent microtubule nucleation in interphase plant cells.
abstract: Microtubule (MT)-dependent MT nucleation by γ-tubulin is required for interphase plant cells to establish a highly dynamic cortical MT network underneath the plasma membrane, which influences the deposition of cell wall materials and consequently governs patterns of directional cell expansion. Newly formed MTs either assume 40° angles or are parallel to the extant ones. To date, it has been enigmatic how the γ-tubulin complex is recruited to the sidewall of cortical MTs and initiates MT nucleation. Here, we discovered that the augmin complex was recruited to cortical MTs and initiated MT nucleation in both branching and parallel forms. The augmin complex overwhelmingly colocalized with the γ-tubulin complex. When the function of the augmin complex was compromised, MT nucleation frequency was drastically reduced, most obviously for the branching nucleation. Consequently, the augmin knockdown cells displayed highly parallel and bundled MTs, replacing the fine and mesh-like MT network in the wild-type cells. Our findings uncovered a mechanism by which the augmin complex functions in recruiting the γ-tubulin complex to cortical MTs and initiating MT nucleation, and they shifted the paradigm of the commonly perceived mitotic-specific function of augmin and established its crucial function in MT-dependent MT nucleation in interphase plant cells.
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Juan
authors.initials: J
authors.lastname: Tian
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Guangda
authors.initials: G
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Yu
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Chaofeng
authors.initials: C
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yinping
authors.initials: Y
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Xiaxia
authors.initials: X
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
authors.forename: Guixian
authors.initials: G
authors.lastname: Xia
authors.affiliation: Department of Plant Biology, University of California, Davis, CA 95616, USA.
authors.forename: Bo
authors.initials: B
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: zskong@im.ac.cn.
authors.forename: Zhaosheng
authors.initials: Z
authors.lastname: Kong
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000032:analysis / Q000378:metabolism / Q000502:physiology*; D049452:Green Fluorescent Proteins / Q000032:analysis; D007399:Interphase / Q000235:genetics / Q000502:physiology*; D008869:Microtubule-Associated Proteins / Q000032:analysis / Q000378:metabolism / Q000502:physiology*; D022101:Microtubule-Organizing Center / Q000378:metabolism; D008870:Microtubules / Q000378:metabolism*; D014404:Tubulin / Q000032:analysis / Q000378:metabolism
chemical_list: C570177:AUG3 protein, Arabidopsis; D029681:Arabidopsis Proteins; D008869:Microtubule-Associated Proteins; D014404:Tubulin; D049452:Green Fluorescent Proteins