RRC ID 12647
Author Nakazawa N, Mehrotra R, Ebe M, Yanagida M.
Title Condensin phosphorylated by the Aurora-B-like kinase Ark1 is continuously required until telophase in a mode distinct from Top2.
Journal J Cell Sci
Abstract Condensin is a conserved protein complex that functions in chromosome condensation and segregation. It has not been previously unequivocally determined whether condensin is required throughout mitosis. Here, we examined whether Schizosaccharomyces pombe condensin continuously acts on chromosomes during mitosis and compared its role with that of DNA topoisomerase II (Top2). Using double mutants containing a temperature-sensitive allele of the condensin SMC2 subunit cut14 (cut14-208) or of top2, together with the cold-sensitive nda3-KM311 mutation (in β-tubulin), temperature-shift experiments were performed. These experiments allowed inactivation of condensin or Top2 at various stages throughout mitosis, even after late anaphase. The results established that mitotic chromosomes require condensin and Top2 throughout mitosis, even in telophase. We then showed that the Cnd2 subunit of condensin (also known as Barren) is the target subunit of Aurora-B-like kinase Ark1 and that Ark1-mediated phosphorylation of Cnd2 occurred throughout mitosis. The phosphorylation sites in Cnd2 were determined by mass spectrometry, and alanine and glutamate residue replacement mutant constructs for these sites were constructed. Alanine substitution mutants of Cnd2, which mimic the unphosphorylated protein, exhibited broad mitotic defects, including at telophase, and overexpression of these constructs caused a severe dominant-negative effect. By contrast, glutamate substitution mutants, which mimic the phosphorylated protein, alleviated the segregation defect in Ark1-inhibited cells. In telophase, the condensin subunits in cut14-208 mutant accumulated in lumps that contained telomeric DNA and proteins that failed to segregate. Condensin might thus serve to keep the segregated chromosomes apart during telophase.
Volume 124(Pt 11)
Pages 1795-807
Published 2011-6-1
DOI 10.1242/jcs.078733
PII jcs.078733
PMID 21540296
MeSH Adenosine Triphosphatases / chemistry Adenosine Triphosphatases / genetics Adenosine Triphosphatases / metabolism* Amino Acid Sequence Anaphase Animals Aurora Kinases Chromosome Segregation / genetics Chromosomes, Fungal / genetics Chromosomes, Fungal / metabolism DNA Topoisomerases, Type II / genetics DNA Topoisomerases, Type II / metabolism* DNA-Binding Proteins / chemistry DNA-Binding Proteins / genetics DNA-Binding Proteins / metabolism* Gene Knockout Techniques Molecular Sequence Data Multiprotein Complexes / chemistry Multiprotein Complexes / genetics Multiprotein Complexes / metabolism* Phosphorylation Protein Serine-Threonine Kinases / antagonists & inhibitors Protein Serine-Threonine Kinases / metabolism* Rabbits Schizosaccharomyces / genetics* Schizosaccharomyces / metabolism Schizosaccharomyces pombe Proteins / antagonists & inhibitors Schizosaccharomyces pombe Proteins / genetics Schizosaccharomyces pombe Proteins / metabolism* Telomere / genetics Telomere / metabolism Telophase* Tubulin / genetics Tubulin / metabolism
IF 4.573
Times Cited 41
Yeast strain with GFP-tagged Taz1