Ornithine Decarboxylase Expression Leads to Translocation and Activation of Protein Kinase CK2 in Vivo
Ornithine decarboxylase (ODC) is the key initial enzyme in the biosynthesis of polyamines. Since polyamines have been shown to enhance protein kinase CK2 activity in vitro , ODC was overexpressed to examine the role of polyamines in CK2 regulation in vivo . Infection of Balb/MK cells with an ODC ret...
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Veröffentlicht in: | The Journal of biological chemistry 1997-05, Vol.272 (19), p.12536-12543 |
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Sprache: | eng |
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Zusammenfassung: | Ornithine decarboxylase (ODC) is the key initial enzyme in the biosynthesis of polyamines. Since polyamines have been shown
to enhance protein kinase CK2 activity in vitro , ODC was overexpressed to examine the role of polyamines in CK2 regulation in vivo . Infection of Balb/MK cells with an ODC retrovirus to elevate ODC and polyamine levels increased overall protein phosphorylation
as well as CK2 protein levels and enzyme activity in mimosine- or nocodazole- arrested cells. Immunofluorescence microscopy
and enzyme analyses of subcellular fractions from ODC-overexpressing cells demonstrated translocation of CK2 from the cytoplasm
to the nucleus with no apparent loss of cytoplasmic CK2 activity, suggesting polyamine activation of the remaining cytoplasmic
enzyme. Similarly, K6/ODC transgenic mice exhibited higher ODC and CK2 enzyme activities than their normal littermates. ODC-immunostained cells in
the transgenic skin also stained intensely for CK2 protein. Primary cultures of K6/ODC keratinocytes also exhibited increased ODC and CK2 enzyme activities compared with those from normal littermates. However,
the addition of difluoromethylornithine, a specific ODC inhibitor, to the transgenic keratinocytes reduced both intracellular
polyamine levels and CK2 enzyme activity. These results suggest that polyamines regulate the CK2 enzyme by affecting its cellular
distribution as well as its enzyme activity and levels. |
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ISSN: | 0021-9258 1083-351X |
DOI: | 10.1074/jbc.272.19.12536 |