RRC ID 52728
Author Lee YJ, Hiwatashi Y, Hotta T, Xie T, Doonan JH, Liu B.
Title The Mitotic Function of Augmin Is Dependent on Its Microtubule-Associated Protein Subunit EDE1 in Arabidopsis thaliana.
Journal Curr Biol
Abstract The augmin complex plays an essential role in microtubule (MT)-dependent MT nucleation by recruiting the γ-tubulin complex to MT walls to generate new MTs [1]. The complex contains eight subunits (designated AUG) including AUG8, which is an MT-associated protein (MAP). When this complex is isolated from etiolated seedlings consisting of primarily interphase cells in Arabidopsis thaliana, AUG8 is an integral component [2]. EDE1 (Endosperm DEfective 1) is homologous to AUG8 [3]. Here, we demonstrate that EDE1, but not AUG8, is associated with acentrosomal spindle and phragmoplast MT arrays in patterns indistinguishable from those of the AUG1-7 subunits and the γ-tubulin complex proteins (GCPs) that exhibit biased localization toward MT minus ends. Consistent with this colocalization, EDE1 directly interacts with AUG6 in vivo. Moreover, a partial loss-of-function mutation, ede1-1, compromises the localization of augmin and γ-tubulin on the spindle and phragmoplast MT arrays and leads to serious distortions in spindle MT remodeling during mitosis. However, mitosis continues even when kinetochore fibers are not obviously discernable, and cytokinesis takes place following the formation of elongated bipolar phragmoplast MT arrays in the mutant. Hence, we conclude that the mitotic function of augmin is dependent on its MAP subunit EDE1, which cannot be replaced by AUG8, and that the cell-cycle-dependent function of augmin can be differentially regulated by employing distinct MAP subunits. Our results also illustrate that plant cells can respond flexibly to serious challenges of compromised MT-dependent MT nucleation to complete mitosis and cytokinesis.
Volume 27(24)
Pages 3891-3897.e4
Published 2017-12-18
DOI 10.1016/j.cub.2017.11.030
PII S0960-9822(17)31475-6
PMID 29225022
MeSH Arabidopsis / genetics Arabidopsis / physiology* Arabidopsis Proteins / genetics* Arabidopsis Proteins / metabolism Cytokinesis Kinetochores / metabolism Microtubule-Associated Proteins / genetics* Microtubule-Associated Proteins / metabolism Microtubule-Organizing Center / metabolism Mitosis* Tubulin / metabolism
IF 9.601
Times Cited 13
Arabidopsis / Cultured plant cells, genes pda13229 pda18485