Casein kinase II phosphorylates the eukaryote-specific C-terminal domain of topoisomerase II in vivo.
The decatenation activity of DNA topoisomerase II is essential for viability as eukaryotic cells traverse mitosis. Phosphorylation has been shown to stimulate topoisomerase II activity in vitro. Here we show that topoisomerase II is a phosphoprotein in yeast and that the level of incorporated phosphate is significantly higher at mitosis than in G1. Comparison of tryptic phosphopeptide maps reveals that the major phosphorylation sites in vivo are targets for casein kinase II. Incorporation of phosphate into topoisomerase II is nearly undetectable at the non-permissive temperature in a conditional casein kinase II mutant. The sites modified by casein kinase II are located in the extreme C-terminal domain of topoisomerase II. This domain is absent in prokaryotic and highly divergent among eukaryotic type II topoisomerases, and may serve to regulate functions of topoisomerase II that are unique to eukaryotic cells.
Cardenas
M E
ME
Swiss Institute for Experimental Cancer Research, Epalinges s/Lausanne.
Dang
Q
Q
Glover
C V
CV
Gasser
S M
SM
D000596:Amino Acids / Q000032:analysis; D047390:Casein Kinase II; D002453:Cell Cycle; D004250:DNA Topoisomerases, Type II / Q000235:genetics / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D010449:Peptide Mapping; D010766:Phosphorylation; D011233:Precipitin Tests; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000201:enzymology
D000596:Amino Acids; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D004250:DNA Topoisomerases, Type II