Worden Natasha, Wilkop Thomas E, Esteve Victor Esteva, Jeannotte Richard, Lathe Rahul, Vernhettes Samantha, Weimer Bart, Hicks Glenn, Alonso Jose, Labavitch John, Persson Staffan, Ehrhardt David, Drakakaki Georgia
Departments of Plant Sciences (N.W., T.E.W., V.E.E., J.L., G.D.) and Veterinary Medicine (R.J., B.W.), University of California, Davis, California 95616;Max-Planck-Institute of Molecular Plant Physiology, Science Campus, 14476 Golm, Germany (R.L., S.P.);Institut National de la Recherche Agronomique, Institute Jean-Pierre Bourgin, 78026 Versailles, France (S.V.);Department of Botany and Plant Sciences, University of California, Riverside, California 92521 (G.H.);Department of Plant and Microbial Biology, North Caroline State University, Raleigh, North Carolina 27695 (J.A.);Australian Research Council Centre of Excellence in Plant Cell Walls, School of Botany, University of Melbourne, Parkville, Victoria 3010, Australia (S.P.); andDepartment of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 (D.E.).
Departments of Plant Sciences (N.W., T.E.W., V.E.E., J.L., G.D.) and Veterinary Medicine (R.J., B.W.), University of California, Davis, California 95616;Max-Planck-Institute of Molecular Plant Physiology, Science Campus, 14476 Golm, Germany (R.L., S.P.);Institut National de la Recherche Agronomique, Institute Jean-Pierre Bourgin, 78026 Versailles, France (S.V.);Department of Botany and Plant Sciences, University of California, Riverside, California 92521 (G.H.);Department of Plant and Microbial Biology, North Caroline State University, Raleigh, North Carolina 27695 (J.A.);Australian Research Council Centre of Excellence in Plant Cell Walls, School of Botany, University of Melbourne, Parkville, Victoria 3010, Australia (S.P.); andDepartment of Plant Biology, Carnegie Institution for Science, Stanford, California 94305 (D.E.)
Plant Physiol. 2015 Feb;167(2):381-93. doi: 10.1104/pp.114.249003. Epub 2014 Dec 22.
Cellulose synthase complexes (CSCs) at the plasma membrane (PM) are aligned with cortical microtubules (MTs) and direct the biosynthesis of cellulose. The mechanism of the interaction between CSCs and MTs, and the cellular determinants that control the delivery of CSCs at the PM, are not yet well understood. We identified a unique small molecule, CESA TRAFFICKING INHIBITOR (CESTRIN), which reduces cellulose content and alters the anisotropic growth of Arabidopsis (Arabidopsis thaliana) hypocotyls. We monitored the distribution and mobility of fluorescently labeled cellulose synthases (CESAs) in live Arabidopsis cells under chemical exposure to characterize their subcellular effects. CESTRIN reduces the velocity of PM CSCs and causes their accumulation in the cell cortex. The CSC-associated proteins KORRIGAN1 (KOR1) and POM2/CELLULOSE SYNTHASE INTERACTIVE PROTEIN1 (CSI1) were differentially affected by CESTRIN treatment, indicating different forms of association with the PM CSCs. KOR1 accumulated in bodies similar to CESA; however, POM2/CSI1 dissociated into the cytoplasm. In addition, MT stability was altered without direct inhibition of MT polymerization, suggesting a feedback mechanism caused by cellulose interference. The selectivity of CESTRIN was assessed using a variety of subcellular markers for which no morphological effect was observed. The association of CESAs with vesicles decorated by the trans-Golgi network-localized protein SYNTAXIN OF PLANTS61 (SYP61) was increased under CESTRIN treatment, implicating SYP61 compartments in CESA trafficking. The properties of CESTRIN compared with known CESA inhibitors afford unique avenues to study and understand the mechanism under which PM-associated CSCs are maintained and interact with MTs and to dissect their trafficking routes in etiolated hypocotyls.
质膜（PM）上的纤维素合酶复合体（CSCs）与皮层微管（MTs）对齐，并指导纤维素的生物合成。目前，人们对CSCs与MTs之间相互作用的机制以及控制CSCs在质膜上运输的细胞决定因素还了解甚少。我们鉴定出一种独特的小分子，即CESA运输抑制剂（CESTRIN），它能降低纤维素含量，并改变拟南芥下胚轴的各向异性生长。我们监测了化学处理下活的拟南芥细胞中荧光标记的纤维素合酶（CESAs）的分布和移动性，以表征其亚细胞效应。CESTRIN降低了质膜CSCs的速度，并导致它们在细胞皮层中积累。与CSC相关的蛋白卷曲纤维素合成酶1（KOR1）和POM2/纤维素合酶相互作用蛋白1（CSI1）受CESTRIN处理的影响不同，表明它们与质膜CSCs的结合形式不同。KOR1在类似于CESA的小体中积累；然而，POM2/CSI1解离到细胞质中。此外，MT稳定性发生改变，但没有直接抑制MT聚合，这表明纤维素干扰引发了一种反馈机制。我们使用多种亚细胞标记评估了CESTRIN的选择性，未观察到其形态学效应。在CESTRIN处理下，CESAs与由定位在反式高尔基体网络的植物 syntaxin 61（SYP61）装饰的囊泡之间的关联增加，这表明SYP61区室参与了CESA运输。与已知的CESA抑制剂相比，CESTRIN的特性为研究和理解质膜相关CSCs的维持机制以及它们与MTs的相互作用机制，以及剖析它们在黄化下胚轴中的运输途径提供了独特的途径。
