Phosphorylation of mammalian DNA topoisomerase I and activation by protein kinase C.
Year: 1990
Type: article
Abstract: The influence of mammalian DNA topoisomerase I phosphorylation on enzyme activity has been investigated. Dephosphorylation by calf intestine alkaline phosphatase abolished the DNA relaxing activity of DNA topoisomerase I and the sensitivity of the enzyme to its specific inhibitor, camptothecin. DNA topoisomerase I could be reactivated by incubation with purified protein kinase C. DNA topoisomerase I was then able to relax supercoiled DNA processively, like the native enzyme, and to cleave 32P-end-labeled SV40 DNA fragments at the same sequences as the native enzyme in the presence of camptothecin. These results show that active DNA topoisomerase I is a phosphoprotein and suggest a possible regulatory role of protein kinase on topoisomerase I activity and on its sensitivity to camptothecin.
Source: Journal of Biological Chemistry
Authors: Y Pommier, D Kerrigan, K D Hartman, R I Glazer
Institutions: National Institutes of Health, National Cancer Institute
Language: English
Subfield: Molecular Biology
Domain: Life Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W1595184397