Katanin's severing activity favors bundling of cortical microtubules in plants.
Higher plant cells exhibit interphase microtubule arrays specific to plants, which are essential for their developmental program. These cortical microtubules (CMT) consist of a population of highly dynamic microtubules that are usually organized into bundles in the cortex of the cells. The organization of CMT is intimately linked to the acquisition of specialized functions, and subsequentchanges in their distribution affect their properties. The mechanisms underlying the formation and the distribution of CMT are still unclear, and little is known about the proteins that are involved in this phenomenon. Here we investigated the putative role of katanin, the only known plant microtubule-severing protein, in the organization of CMT. We generated transgenic Arabidopsis lines that overexpress katanin under the control of an ethanol-inducible promoter. In response to an induced overexpression of katanin, CMT organized into numerous and thick bundles, which ultimately depolymerized. From the analyses of CMT patterns together with recent data on CMT dynamics, we propose that, in interphase cells, katanin's main activity is to free CMT, generating motile microtubules that incorporate into bundles.
Stoppin-Mellet
Virginie
V
Laboratoire de Physiologie Cellulaire Végétale, UMR 5168, CNRS/CEA/INRA/Université Joseph Fourier, Département Réponse et Dynamique Cellulaires, 17 rue des Martyrs, F-38054 Grenoble Cedex 9, France.
Gaillard
Jérémie
J
Vantard
Marylin
M
D000251:Adenosine Triphosphatases; D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D000074201:Katanin; D008870:Microtubules / Q000378:metabolism*; D019441:Plant Epidermis / Q000166:cytology / Q000378:metabolism; D030821:Plants, Genetically Modified
D029681:Arabidopsis Proteins; D000251:Adenosine Triphosphatases; C436244:KTN1 protein, Arabidopsis; D000074201:Katanin