Nuclear localization of I kappa B alpha promotes active transport of NF-kappa B from the nucleus to the cytoplasm.
I kappa B alpha tightly regulates the transcriptional activity of NF-kappa B by retaining it in the cytoplasm in an inactive form. In the present work, we report that I kappa B alpha, when expressed in the nuclear compartment, not only abrogates NF-kappa B/DNA interactions and NF-kappa B-dependent transcription, but also transports NF-kappa B back to the cytoplasm. This function of I kappa B alpha is insured by a nuclear export sequence located in the C-terminal domain of I kappa B alpha and homologous to the previously described export signal found in HIV-1 Rev protein as well as in PKI (the inhibitor of the catalytic subunit of protein kinase A). Thus, inhibition of NF-kappa B/DNA binding and the consecutive efficient nuclear export of the transcription factor of I kappa B alpha could represent an important mechanism for the control of the expression of NF-kappa B-dependent genes.
Arenzana-Seisdedos
F
F
Unité d'Immunologie Virale, Institut Pasteur, Paris, France.
Turpin
P
P
Rodriguez
M
M
Thomas
D
D
Hay
R T
RT
Virelizier
J L
JL
Dargemont
C
C
D000595:Amino Acid Sequence; D000818:Animals; D001693:Biological Transport, Active; D002467:Cell Nucleus / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005260:Female; D006367:HeLa Cells; D006801:Humans; D020672:I-kappa B Proteins; D008969:Molecular Sequence Data; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D009865:Oocytes; D014158:Transcription, Genetic; D014162:Transfection; D014982:Xenopus laevis
D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D000072000:NF-KappaB Inhibitor alpha