title: Regulation of katanin activity in the ciliate Tetrahymena thermophila.
abstract: Katanin is a microtubule severing protein that functions as a heterodimer composed of an AAA domain catalytic subunit, p60, and a regulatory subunit, a WD40 repeat protein, p80. Katanin-dependent severing of microtubules is important for proper execution of key cellular activities including cell division, migration, and differentiation. Published data obtained in Caenorhabditis elegans, Xenopus and mammals indicate that katanin is regulated at multiple levels including transcription, posttranslational modifications (of both katanin and microtubules) and degradation. Little is known about how katanin is regulated in unicellular organisms. Here we show that in the ciliated protist Tetrahymena thermophila, as in Metazoa, the localization and activity of katanin requires specific domains of both p60 and p80, and that the localization of p60, but not p80, is sensitive to the levels of microtubule glutamylation. A prolonged overexpression of either a full length, or a fragment of p80 containing WD40 repeats, partly phenocopies a knockout of p60, indicating that in addition to its activating role, p80 could also contribute to the inhibition of p60. We also show that the level of p80 depends on the 26S proteasome activity.
authors.affiliation: Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str, Warsaw, 02-093, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Waclawek
authors.affiliation: Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str, Warsaw, 02-093, Poland.
authors.forename: Ewa
authors.initials: E
authors.lastname: Joachimiak
authors.affiliation: Laboratory of Molecular and Systemic Neuromorphology, Department of Neurophysiology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str, Warsaw, 02-093, Poland.
authors.forename: Malgorzata Hanna
authors.initials: MH
authors.lastname: Hall
authors.affiliation: Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str, Warsaw, 02-093, Poland.
authors.forename: Hanna
authors.initials: H
authors.lastname: Fabczak
authors.affiliation: Laboratory of Cytoskeleton and Cilia Biology, Department of Cell Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Str, Warsaw, 02-093, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Wloga
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D006868:Hydrolysis; D017136:Ion Transport; D000074201:Katanin; D008870:Microtubules / Q000378:metabolism*; D000072417:Protein Domains; D016808:Tetrahymena thermophila / Q000235:genetics / Q000378:metabolism*; D014404:Tubulin / Q000378:metabolism
chemical_list: D014404:Tubulin; D000251:Adenosine Triphosphatases; D000074201:Katanin