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TY - JOUR AU - Guerra, Barbara AU - Götz, Claudia AU - Wagner, Peter AU - Montenarh, Mathias AU - Issinger, Olaf-Georg PY - 1997 DA - 1997/06/01 TI - The carboxy terminus of p53 mimics the polylysine effect of protein kinase CK2-catalyzed MDM2 phosphorylation JO - Oncogene SP - 2683 EP - 2688 VL - 14 IS - 22 AB - The oncogene product MDM2 can be phosphorylated by protein kinase CK2 in vitro 0.5 – 1 mol of phosphate were incorporated per mol MDM2 protein. The catalytic subunit of protein kinase CK2 (α-subunit) catalyzed the incorporation of twice as much phosphate into the MDM2 protein as it was obtained with the holoenzyme. Polylysine stimulated MDM2 phosphorylation by CK2 holoenzyme threefold in contrast to the α-subunit-catalyzed MDM2 phosphorylation which was reduced by about 66% when polylysine was added. Full length p53, but also a peptide representing a C-terminal fragment of the tumor suppressor gene product p53 (amino acids 264 – 393 which also harbors the CK2β interaction site at amino acids 287 – 340) mimicked the polylysine effect in all respects, ie. stimulation of phosphate incorporation by CK2 holoenzyme and inhibition in the presence of the catalytic CK2 α-subunit. Stimulation by p53264 – 393 was on the average close to twofold and inhibition in the case of the α-subunit-catalyzed MDM2 phosphorylation was about 40%. Phosphorylation of MDM2 by CK2 holoenzyme in the presence of the p21WAF1/CIP1, known to be a potent inhibitor of cyclin-dependent protein kinases, also led to a significant reduction of phosphate incorporation into MDM2 indicating that p21WAF1/CIP1 does not exclusively inhibit cell cycle kinases. Furthermore, these data add new insight into the autoregulatory loop which include p21WAF1/CIP1, MDM2 protein, CK2 and p53. SN - 1476-5594 UR - https://doi.org/10.1038/sj.onc.1201112 DO - 10.1038/sj.onc.1201112 ID - Guerra1997 ER -