XXXX -mediated association of protein kinase C to the nuclear fraction in NIH 3T3 cells.

@entity1 @entity5 @entity4621 @entity865 @entity141 @entity864 @entity855
Treatment of intact NIH 3T3 cells with @entity864 ( @entity865 ) causes a rapid redistribution (stabilization) of protein kinase C to the particulate fraction. Part of the enzyme activity stabilized to the membrane fraction in response to @entity865 can be recovered associated with nuclear-cytoskeletal components. An apparently pure nuclear fraction prepared from NIH 3T3 cells was found to contain 25-30% of the total membrane-associated protein kinase C activity when isolated in the presence of @entity141 . In untreated control cells, most of this activity found with the nuclear fraction can be extracted by chelators. @entity4621 ( @entity865 ) treatment of NIH 3T3 cells induces the tight association of protein kinase C to the nucleus; this tightly bound activity is not dissociable by chelators and can be recovered only by solubilization with detergent. Nuclei purified from untreated @entity1 promyelocytic leukemic HL-60 cells contain higher amounts of chelator-stable, detergent-extractable protein kinase C activity compared with control NIH 3T3 cells. However, @entity865 treatment of HL-60 cells does not enhance the amount of protein kinase C found tightly associated with the nuclear fraction. Immunohistochemical studies with polyclonal antibodies directed against protein kinase C further indicate that @entity865 treatment of NIH 3T3 cells does significantly enhance the amount of protein kinase C found tightly associated with the nucleus and cytoskeleton, whereas exposure of HL-60 cells to @entity865 does not appreciably alter the amount of protein kinase C observed to be associated with the nuclear fraction. The @entity865 -mediated association (activation) of protein kinase C to the nuclear and cytoskeletal fractions with NIH 3T3 cells is further supported by the enhanced phosphorylation of specific endogenous proteins noted when purified nuclei and cytoskeletal preparations are incubated with [gamma-32P] @entity855 . These results suggest that @entity5 promoters may induce association (activation) of protein kinase C with different subcellular components to alter the availability of endogenous substrates. This may result in differential responses by different cell types during exposure to @entity5 promoters.
