Nm. Hasan et al., INDUCTION AND PHOSPHORYLATION OF PROTEIN-KINASE C-ALPHA AND MITOGEN-ACTIVATED PROTEIN-KINASE BY HYPOXIA AND BY RADIATION IN CHINESE-HAMSTERV79 CELLS, Radiation research, 145(2), 1996, pp. 128-133
Protein kinase C (PKC) and mitogen-activated protein (MAP) kinase are
protein-serine/threonine kinases which are important regulators of div
erse cellular processes including metabolism, proliferation and differ
entiation. This study shows that both hypoxia and X irradiation of ser
um-deprived Chinese hamster V79 cells cause the induction and phosphor
ylation of the PKC-alpha isoform. The increased induction and phosphor
ylation of PKC occur mainly in the nuclear fraction. Unlike the PKC ac
tivator TPA, neither hypoxic nor radiation stress causes translocation
of PKC-alpha from the cytosol to the membrane. The induction of PKC-a
lpha by hypoxia is accompanied by an increased expression of MAP kinas
e but, in contrast, this does not occur when PKC-alpha is induced by r
adiation. Radiation, like TPA, cause a complete redistribution of MAP
kinase from the cytosol to the nucleus. (C) 1996 by Radiation Research
Society.