Serum‐stimulated cell cycle entry of fibroblasts requires undisturbed phosphorylation and non‐phosphorylation interactions of the catalytic subunits of protein kinase CK2

FEBS Letters

Pyerin, Walter¹  Simoes-Wuest, Paula¹  Ackermann, Karin¹  Lorenz, Peter¹ 

[1] Biochemische Zellphysiologie B0200, Deutsches Krebsforschungszentrum, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany

关键词: Protein kinase CK2 (casein kinase II);    Cell cycle signaling;    Human lung fibroblast;    Microinjection;    Serum stimulation;    Gene expression;    ADA;    peptide RRRADDADDDDD;    ADS;    peptide RRRADDSDDDDD;    XX;    peptide DDRDDRDADADR;    BrdU;    5-bromo-2′-deoxyuridine;    DTAF;    5-(4;    6-dichloro-triazinyl)aminofluorescein;    PBS;    phosphate-buffered saline;    TRITC;    tetramethylrhodamine isothiocyanate;    SDS-PAGE;    polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate;    PVDF;    polyvinylidene difluoride;   

DOI  :  10.1016/S0014-5793(99)00388-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Protein kinase CK2 is a pleiotropic Ser/Thr kinase occurring as α₂β₂, α′₂β₂, or αα′β₂ tetramers. A requirement in serum-stimulated cell cycle entry in both the cytoplasm and the nucleus of human fibroblasts for phosphorylation(s) by CK2 has been concluded from stimulation inhibition by microinjected antibodies against the regulatory subunit (β). We have now examined this idea more directly by microinjection-mediated perturbation of phosphorylation and non-phosphorylation interactions of the catalytic subunits (α and α′), and by verifying the supposed matching of the cellular partition of CK2 subunits in the fibroblasts employed. While immunostaining and cell fractionation indicate that the partitions of subunits indeed match each other (with their predominant location in the nucleus in both quiescent and serum-stimulated cells), microinjection of substrate or pseudosubstrate peptides competing for the CK2-mediated phosphorylation in vitro resulted in significant inhibition of serum stimulation when placed into the nucleus but not when placed into the cytoplasm. Also inhibitory were nuclear but not cytoplasmic injections of antibodies against α and α′ that affect neither their kinase activity in vitro nor their complexing to β. The data indicate that the role played by CK2 in serum-stimulated cell cycle entry is predominantly nuclear and more complex than previously assumed, involving not only phosphorylation but also experimentally separable non-phosphorylation interactions by the catalytic subunits.

【 授权许可】

Unknown