Katanin regulates dynamics of microtubules and biogenesis of motile cilia.
The in vivo significance of microtubule severing and the mechanisms governing its spatial regulation are not well understood. In Tetrahymena, a cell type with elaborate microtubule arrays, we engineered null mutations in subunits of the microtubule-severing complex, katanin. We show that katanin activity is essential. The net effect of katanin on the polymer mass depends on the microtubule type and location. Although katanin reduces the polymer mass and destabilizes the internal network of microtubules, its activity increases the mass of ciliary microtubules. We also show that katanin reduces the levels of several types of post-translational modifications on tubulin of internal and cortical microtubules. Furthermore, katanin deficiencies phenocopy a mutation of beta-tubulin that prevents deposition of polymodifications (glutamylation and glycylation) on microtubules. We propose that katanin preferentially severs older, post-translationally modified segments of microtubules.
Sharma
Neeraj
N
Department of Cellular Biology, University of Georgia, Athens, GA 30602, USA.
Bryant
Jessica
J
Wloga
Dorota
D
Donaldson
Rachel
R
Davis
Richard C
RC
Jerka-Dziadosz
Maria
M
Gaertig
Jacek
J
D000251:Adenosine Triphosphatases / Q000235:genetics / Q000502:physiology*; D000818:Animals; D002923:Cilia / Q000502:physiology / Q000648:ultrastructure; D000074201:Katanin; D008870:Microtubules / Q000502:physiology*; D009154:Mutation; D010802:Phylogeny; D011499:Protein Processing, Post-Translational; D015800:Protozoan Proteins / Q000235:genetics / Q000502:physiology*; D016808:Tetrahymena thermophila / Q000502:physiology* / Q000648:ultrastructure; D014404:Tubulin / Q000378:metabolism
D015800:Protozoan Proteins; D014404:Tubulin; D000251:Adenosine Triphosphatases; D000074201:Katanin