A dominant negative protein kinase C zeta subspecies blocks NF-kappa B activation.
Nuclear factor kappa B (NF-kappa B) plays a critical role in the regulation of a number of genes. NF-kappa B is a heterodimer of 50- and 65-kDa subunits sequestered in the cytoplasm complexed to inhibitory protein I kappa B. Following stimulation of cells, I kappa B dissociates from NF-kappa B, allowing its translocation to the nucleus, where it carries out the transactivation function. The precise mechanism controlling NF-kappa B activation and the involvement of members of the protein kinase C (PKC) family of isotypes have previously been investigated. It was found that phorbol myristate acetate, (PMA) which is a potent stimulant of phorbol ester-sensitive PKC isotypes, activates NF-kappa B. However, the role of PMA-sensitive PKCs in vivo is not as apparent. It has recently been demonstrated in the model system of Xenopus laevis oocytes that the PMA-insensitive PKC isotype, zeta PKC, is a required step in the activation of NF-kappa B in response to ras p21. We demonstrate here that overexpression of zeta PKC is by itself sufficient to stimulate a permanent translocation of functionally active NF-kappa B into the nucleus of NIH 3T3 fibroblasts and that transfection of a kinase-defective dominant negative mutant of zeta PKC dramatically inhibits the kappa B-dependent transactivation of a chloramphenicol acetyltransferase reporter plasmid in NIH 3T3 fibroblasts. All these results support the notion that zeta PKC plays a decisive role in NF-kappa B regulation in mammalian cells.
Diaz-Meco
M T
MT
Centro de Biología Molecular, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Spain.
Berra
E
E
Municio
M M
MM
Sanz
L
L
Lozano
J
J
Dominguez
I
I
Diaz-Golpe
V
V
Lain de Lera
M T
MT
Alcamí
J
J
Payá
C V
CV
Arenzana-Seisedos
F
F
Virelizier
J L
JL
Moscat
J
J
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D002451:Cell Compartmentation; D003001:Cloning, Molecular; D004742:Enhancer Elements, Genetic; D005786:Gene Expression Regulation; D005799:Genes, Dominant; D066298:In Vitro Techniques; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D016328:NF-kappa B / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D011493:Protein Kinase C / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection; D000099221:Protein Kinase C zeta
D016328:NF-kappa B; D009838:Oligodeoxyribonucleotides; D011493:Protein Kinase C; D000099221:Protein Kinase C zeta