casein-kinase-ii and Teratocarcinoma

Knocking out the regulatory beta subunit of protein kinase CK2 in mice leads to early embryonic lethality. Heterozygous CK2beta (CK2beta+/-) knockout mice do not show an obvious phenotype. However, the number of heterozygous offsprings from CK2B+/- inter-crossings is lower than expected, meaning that some heterozygous embryos do not survive. Interestingly, CK2beta+/- ES (Embryonic Stem) cells express a considerably lower level of CK2beta than wild-type ES cells, whereas the level of CK2beta in organs from heterozygous adult mice does not significantly differ from those of wild-type mice. The data suggest a compensatory mechanism that adjusts CK2beta levels during development in the majority of, but not in all, cases (Mol Cell Biol 23: 908-915, 2003). In order to find an explanation for the gene dosage effect observed for heterozygous offsprings, we analysed embryos at mid-gestation (E10.5) as well as wild-type and CK2beta+/- ES cells for differences in growth rate and response to different stress agents. Analysis of E10.5 embryos generated from heterozygous matings revealed about 20% of smaller retarded CK2beta+/- embryos. No correlation between CK2beta levels in normal looking and retarded CK2beta+/- embryos were found. However, a different post-translational form of CK2beta protein has been detected in these retarded embryos. Cellular parameters such as growth rate and G1-, G2-checkpoints in ES cells were identical in both wild-type and CK2beta+/- cells. When ES cells were injected to induce differentiated teratocarcinoma in syngenic mice, the size of the tumours correlated with the level of CK2beta.

Topics: Animals; Casein Kinase II; Cell Cycle; Embryo, Mammalian; Gene Dosage; Heterozygote; Mice; Mice, Knockout; Phenotype; Protein Subunits; Stem Cells; Teratocarcinoma

Using the murine teratocarcinoma cell line F9 we investigated the influence of serum stimulation and cisplatin treatment on the p53, CK2, MDM2 levels. Both treatments led to an increase of p53, though with different kinetics; the other proteins investigated were not affected. We present direct evidence by immunoprecipitation for an association of protein kinase CK2 holoenzyme (alpha2beta2), p53, and the ribosomal protein L5. The results suggest complexes between the CK2 holoenzyme and p53 but also p53/CKbeta complexes. Furthermore we provide evidence for the existence of high molecular mass complexes of CK2 in vivo. This is the first evidence that, under physiological conditions, protein kinase CK2 does not exist solely as a heterotetramer, but predominantly in association with other proteins.

Topics: Animals; Antineoplastic Agents; Blood Proteins; Casein Kinase II; Cisplatin; Mice; Precipitin Tests; Protein Binding; Protein Serine-Threonine Kinases; Ribosomal Proteins; Teratocarcinoma; Tumor Cells, Cultured; Tumor Suppressor Protein p53

The effect of cis-diaminedichloroplatinum(II) (cisplatin) on the induction of p53 and protein kinase CK2 activity was studied in the mouse teratocarcinoma cell line F9. Treatment of the cells with the chemotherapeutic agent cisplatin led to the detection of p53 3 h after addition of the drug. F9 cell extracts treated with and without cisplatin were analyzed by ion exchange chromatography for protein kinase CK2 alpha/beta subunits and p53 distribution. The following results were obtained: (a) in crude extracts of cisplatin-treated cells, CK2 activity was sometimes reduced by as much as 50%; (b) after separation by anionic exchange chromatography (MA7Q, BioRad) of the crude cellular extracts from cisplatin-treated cells, lower CK2 activity was found in the peak fractions confirming the results obtained with crude cellular extracts; (c) besides the detection of CK2 alpha subunit by immunostaining, we have detected, at a concentration of approximately 200 mM NaCl, a protein of approximately 46 kDa which reacted with the CK2 alpha-specific antibody. This fraction was devoid of CK2 activity; and (d) cisplatin-treated cells exhibited p53 protein, which was mostly eluting ahead but also partly together with CK2 holoenzyme.

Topics: Amino Acid Sequence; Animals; Casein Kinase II; Chromatography, Ion Exchange; Cisplatin; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Mice; Molecular Sequence Data; Neoplasm Proteins; Phosphorylation; Protein Conformation; Protein Processing, Post-Translational; Protein Serine-Threonine Kinases; Recombinant Fusion Proteins; Teratocarcinoma; Tumor Cells, Cultured; Tumor Suppressor Protein p53