Glycogen synthase kinase-3 enhances nuclear export of a Dictyostelium STAT protein
AUTOR(ES)
Ginger, Rebecca S.
FONTE
Oxford University Press
RESUMO
Extracellular cAMP stimulates the rapid tyrosine phosphorylation and nuclear translocation of the Dictyostelium STAT protein Dd-STATa. Here we show that it also induces serine phosphorylation by GskA, a homologue of glycogen synthase kinase-3 (GSK-3). Tyrosine phosphorylation occurs within 10 s of stimulation, whereas serine phosphorylation takes 5 min, matching the kinetics observed for the cAMP regulation of GskA. Phosphorylation by GskA enhances nuclear export of Dd-STATa. The phosphorylated region, however, is not itself a nuclear export signal and we identify a region elsewhere in the protein that mediates nuclear export. These results suggest a biphasic regulation of Dd-STATa, in which extracellular cAMP initially directs nuclear import and then, via GskA, promotes its subsequent export. It also raises the possibility of an analogous regulation of STAT nuclear export in higher eukaryotes.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=314011Documentos Relacionados
- Regulation of Serotonin 1B Receptor by Glycogen Synthase Kinase-3
- Modulation of the glycogen synthase kinase-3 family by tyrosine phosphorylation.
- Wingless inactivates glycogen synthase kinase-3 via an intracellular signalling pathway which involves a protein kinase C.
- Expression and characterization of glycogen synthase kinase-3 mutants and their effect on glycogen synthase activity in intact cells.
- Yeast Glycogen Synthase Kinase-3 Activates Msn2p-dependent Transcription of Stress Responsive Genes