Cooperative transcriptional activity of Jun and Stat3 beta, a short form of Stat3.

AUTOR(ES)

Schaefer, T S

RESUMO

To identify proteins that regulate the transcriptional activity of c-Jun, we have used the yeast two-hybrid screen to detect mammalian polypeptides that might interact functionally with the N-terminal segment of c-Jun, a known regulatory region. Among the proteins identified is a short form of Stat3 (designated Stat3 beta). Stat3 beta is missing the 55 C-terminal amino acid residues of the long form (Stat3 alpha) and has 7 additional amino acid residues at its C terminus. In the absence of added cytokines, expression of Stat3 beta (but not Stat3 alpha) in transfected cells activated a promoter containing the interleukin 6 responsive element of the rat alpha 2-macroglobulin gene; coexpression of Stat3 beta and c-Jun led to enhanced cooperative activation of the promoter. Nuclear extracts of cells transfected with a Stat3 beta expression plasmid formed a complex with an oligonucleotide containing a Stat3 binding site, whereas extracts of cells transfected with a Stat3 alpha plasmid did not. We conclude that there is a short form of Stat3 (Stat3 beta), that Stat3 beta is transcriptionally active under conditions where Stat3 alpha is not, and that Stat3 beta and c-Jun are capable of cooperative activation of certain promoters.

Documentos Relacionados

• Interacting Regions in Stat3 and c-Jun That Participate in Cooperative Transcriptional Activation
• Mapping of Stat3 serine phosphorylation to a single residue (727) and evidence that serine phosphorylation has no influence on DNA binding of Stat1 and Stat3.
• Activation of Smad transcriptional activity by protein inhibitor of activated STAT3 (PIAS3)
• Requirement for Ras/Rac1-Mediated p38 and c-Jun N-Terminal Kinase Signaling in Stat3 Transcriptional Activity Induced by the Src Oncoprotein
• Reduction of Stat3 Activity Attenuates HIV-Induced Kidney Injury