Title: Characterization and physiological importance of a novel cell cycle regulated protein kinase in Xenopus laevis oocytes that phosphorylates cyclin B2
Authors: Derua, Rita ×
Stevens, I
Waelkens, Etienne
Fernandez, A
Lamb, N
Merlevede, Wilfried
Goris, Jozef #
Issue Date: Mar-1997
Series Title: Experimental Cell Research vol:230 issue:2 pages:310-24
Abstract: We have partially purified a specific cyclin B2 kinase (cyk) from prophase oocytes of Xenopus laevis after an ATP-gamma-S activation step. Phosphopeptide analysis identified Ser53 as the major in vitro phosphorylation site for cyk in cyclin B2. Using a synthetic peptide derived from cyclin B2 encompassing Ser53 (cyktide) as a substrate, cyk was shown to be activated during progesterone-induced maturation, with a peak of activity between 40 and 50% maturation. A sustained high cyk activity was observed in oscillating egg extracts. Microinjection of cyk-phosphorylated cyclin B2 into prophase oocytes accelerated progesterone-induced maturation by about 2 h, indicating that cyclin B2 is a relevant substrate for cyk and that the function of cyk is situated upstream of cdc2-cyclin B activation. Microinjection of cyk-phosphorylated cyktide or a combination of cyk and cyclin B1 into G2 fibroblasts induced significant changes in cell morphology, reminiscent of a premature prophase-like phenotype. Similarly, addition of cyk-phosphorylated cyktide in cyclin B1-dependent interphase extracts resulted in histone H1 kinase activation.
ISSN: 0014-4827
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Biochemistry Section (Medicine) (-)
Laboratory of Protein Phosphorylation and Proteomics
Laboratory of Phosphoproteomics (-)
× corresponding author
# (joint) last author

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