title: Asator, a tau-tubulin kinase homolog in Drosophila localizes to the mitotic spindle.
abstract: We have used a yeast two-hybrid interaction assay to identify Asator, a tau-tubulin kinase homolog in Drosophila that interacts directly with the spindle matrix protein Megator. Using immunocytochemical labeling by an Asator-specific mAb as well as by transgenic expression of a GFP-labeled Asator construct, we show that Asator is localized to the cytoplasm during interphase but redistributes to the spindle region during mitosis. Determination of transcript levels using qRT-PCR suggested that Asator is expressed throughout development but at relatively low levels. By P-element excision, we generated a null or strong hypomorphic Asator(exc) allele that resulted in complete adult lethality when homozygous, indicating that Asator is an essential gene. That the observed lethality was caused by impaired Asator function was further supported by the partial restoration of viability by transgenic expression of Asator-GFP in the Asator(exc) homozygous mutant background. The finding that Asator localizes to the spindle region during mitosis and directly can interact with Megator suggests that its kinase activity may be involved in regulating microtubule dynamics and microtubule spindle function.
authors.affiliation: Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, Iowa 50011, USA.
authors.forename: Hongying
authors.initials: H
authors.lastname: Qi
authors.forename: Changfu
authors.initials: C
authors.lastname: Yao
authors.forename: Weili
authors.initials: W
authors.lastname: Cai
authors.forename: Jack
authors.initials: J
authors.lastname: Girton
authors.forename: Kristen M
authors.initials: KM
authors.lastname: Johansen
authors.forename: Jørgen
authors.initials: J
authors.lastname: Johansen
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics* / Q000378:metabolism*; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D008938:Mitosis / Q000235:genetics / Q000502:physiology; D034521:Nuclear Matrix-Associated Proteins / Q000378:metabolism; D010802:Phylogeny; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D017385:Sequence Homology; D008941:Spindle Apparatus / Q000378:metabolism*; D014018:Tissue Distribution
chemical_list: D029721:Drosophila Proteins; C498867:Mtor protein, Drosophila; D034521:Nuclear Matrix-Associated Proteins; D005982:Glutathione Transferase; D011494:Protein Kinases; C547735:asator protein, Drosophila; C095903:tau-tubulin kinase; D017346:Protein Serine-Threonine Kinases