The Membrane-Associated Sec1/Munc18 KEULE is Required for Phragmoplast Microtubule Reorganization During Cytokinesis in Arabidopsis

• Published in: Molecular plant Vol. 9; no. 4; pp. 528 - 540
• Main Authors: Steiner, Alexander, Müller, Lin, Rybak, Katarzyna, Vodermaier, Vera, Facher, Eva, Thellmann, Martha, Ravikumar, Raksha, Wanner, Gerhard, Hauser, Marie-Theres, Assaad, Farhah F.
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 04-04-2016
• Subjects: Arabidopsis - cytology; Arabidopsis - genetics; Arabidopsis - metabolism; Cell Membrane - metabolism; cell plate; Cytokinesis; KEULE; KNOLLE; Microtubules - metabolism; Munc18 Proteins - genetics; Munc18 Proteins - metabolism; Mutation; phragmoplast microtubule; PLEIADE/MAP65-3; Protein Transport; 微管动力学; 成膜; 拟南芥; 组织缺陷; 细胞分裂; 细胞动力学; 胞质分裂; 重组; phragmoplast microtubule; KNOLLE; KEULE; cytokinesis; cell plate; PLEIADE/MAP65-3
• ISSN: 1674-2052; 1752-9867
• DOI: 10.1016/j.molp.2015.12.005

Cytokinesis, the partitioning of the cytoplasm following nuclear division, requires extensive coordination between membrane trafficking and cytoskeletal dynamics. In plants, the onset of cytokinesis is characterized by the assembly of a bipolar microtubule array, the phragmoplast, and of a transient membrane compartment, the cell plate. Little is known about the coordination between membrane deposition at the cell plate and the dynamics of phragmoplast microtubules. In this study, we monitor the localization dynamics of microtubule and membrane markers throughout cytokinesis. Our spatiotemporal resolution is consistent with the general view that microtubule dynamics drive membrane movements. Nonetheless, we provide evidence for active sorting at the cell plate and show that this is, at least in part, mediated by the TRAPPII tethering complex. We also characterize phragmoplast microtubule organization and cell plate formation in a suite of cytokinesis-defective mutants. Of four mutant lines with defects in phragmoplast microtubule organization, only morl microtubule-associated mutants exhibited aberrant cell plates. Conversely, the mutants with the strongest impairment in phragmoplast microtubule reorganization are keule alleles, which have a primary defect in membrane fusion. Our findings identify the SEC1/Munc18 protein KEULE as a central regulatory node in the coordination of membrane and microtubule dynamics during plant cytokinesis.