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Inhibition of endothelin‐mediated topoisomerase I activation by pertussis toxin
Author(s) -
Nambi Ponnal,
Wu Hsiao-Ling,
Woessner Richard D.,
Mattern Michael R.
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80496-6
Subject(s) - pertussis toxin , endothelin receptor , endothelin 1 , enzyme , receptor , microbiology and biotechnology , toxin , incubation , chemistry , topoisomerase , g protein , biology , biochemistry
Cultured rat mesangial cells contain high affinity endothelin (ET) receptors at high densities. Exposure of these cells to ET resulted in a transient activation of topoisomerase I extractable activity, which reached its maximum value at approximately 2 min and returned to basal value after approximately 10 min of treatment. The activation of this enzyme was dependent upon the concentration of ET added. Incubation of the cells with pertussis toxin inhibited ET‐induced increases in topoisomerase I activity in a concentration‐dependent manner, suggesting the involvement of pertussis toxin‐sensitive GTP‐binding protein in ET‐mediated action. Endothelin had no detectable effect upon extractable topoisomerase II activity.