title: Salt stress-induced disassembly of Arabidopsis cortical microtubule arrays involves 26S proteasome-dependent degradation of SPIRAL1.
abstract: The dynamic instability of cortical microtubules (MTs) (i.e., their ability to rapidly alternate between phases of growth and shrinkage) plays an essential role in plant growth and development. In addition, recent studies have revealed a pivotal role for dynamic instability in the response to salt stress conditions. The salt stress response includes a rapid depolymerization of MTs followed by the formation of a new MT network that is believed to be better suited for surviving high salinity. Although this initial depolymerization response is essential for the adaptation to salt stress, the underlying molecular mechanism has remained largely unknown. Here, we show that the MT-associated protein SPIRAL1 (SPR1) plays a key role in salt stress-induced MT disassembly. SPR1, a microtubule stabilizing protein, is degraded by the 26S proteasome, and its degradation rate is accelerated in response to high salinity. We show that accelerated SPR1 degradation is required for a fast MT disassembly response to salt stress and for salt stress tolerance.
authors.affiliation: Plant Physiology, Biochemistry, Molecular Biology Program, Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546, USA.
authors.forename: Songhu
authors.initials: S
authors.lastname: Wang
authors.forename: Jasmina
authors.initials: J
authors.lastname: Kurepa
authors.forename: Takashi
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Jan A
authors.initials: JA
authors.lastname: Smalle
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001549:Benzamides / Q000494:pharmacology; D004136:Dinitrobenzenes / Q000494:pharmacology; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008870:Microtubules / Q000502:physiology*; D009154:Mutation; D030821:Plants, Genetically Modified / Q000235:genetics / Q000502:physiology; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism*; D059748:Proteolysis; D055051:Salt-Tolerant Plants / Q000235:genetics / Q000502:physiology; D012965:Sodium Chloride / Q000494:pharmacology*; D013312:Stress, Physiological; D013424:Sulfanilamides / Q000494:pharmacology
chemical_list: D029681:Arabidopsis Proteins; D001549:Benzamides; D004136:Dinitrobenzenes; D008869:Microtubule-Associated Proteins; C487570:SPR1 protein, Arabidopsis; D013424:Sulfanilamides; C001059:pronamide; D012965:Sodium Chloride; C012465:oryzalin; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease