title: Tousled-mediated activation of Aurora B kinase does not require Tousled kinase activity in vivo.
abstract: The Aurora kinases comprise an evolutionarily conserved protein family that is required for a variety of cell division events, including spindle assembly, chromosome segregation, and cytokinesis. Emerging evidence suggests that once phosphorylated, a subset of Aurora substrates can enhance Aurora kinase activity. Our previous work revealed that the Caenorhabditis elegans Tousled-like kinase TLK-1 is a substrate and activator of the AIR-2 Aurora B kinase in vitro and that partial loss of TLK-1 enhances the mitotic defects of an air-2 mutant. However, given that these experiments were performed in vitro and with partial loss of function alleles in vivo, a necessary step forward in our understanding of the relationship between the Aurora B and Tousled kinases is to prove that TLK-1 expression is sufficient for Aurora B activation in vivo. Here, we report that heterologous expression of wild-type and kinase-inactive forms of TLK-1 suppresses the lethality of temperature-sensitive mutants of the yeast Aurora B kinase Ipl1. Moreover, kinase-dead TLK-1 associates with and augments the activity of Ipl1 in vivo. Together, these results provide critical and compelling evidence that Tousled has a bona fide kinase-independent role in the activation of Aurora B kinases in vivo.
authors.affiliation: Department of Molecular Genetics, M.D Anderson Cancer Center, University of Texas, Houston, Texas 77030, USA.
authors.forename: Gary M
authors.initials: GM
authors.lastname: Riefler
authors.forename: Sharon Y R
authors.initials: SY
authors.lastname: Dent
authors.forename: Jill M
authors.initials: JM
authors.lastname: Schumacher
mesh_terms: D000818:Animals; D064127:Aurora Kinases; D017173:Caenorhabditis elegans; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D005804:Genes, Lethal / Q000235:genetics; D047908:Intracellular Signaling Peptides and Proteins; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D047908:Intracellular Signaling Peptides and Proteins; D029701:Saccharomyces cerevisiae Proteins; D011494:Protein Kinases; D064127:Aurora Kinases; C576961:IPL1 protein, S cerevisiae; D017346:Protein Serine-Threonine Kinases