Tyrosine phosphorylation-independent nuclear translocation of a dictyostelium STAT in response to DIF signaling.
We describe a Dictyostelium STAT, Dd-STATc, which regulates the speed of early development and the timing of terminal differentiation. Dd-STATc also functions as a repressor, which directs graded expression of the ecmA gene in different prestalk cell populations. Developing Dictyostelium cells produce a chlorinated hexaphenone, DIF, which directs prestalk cell differentiation. Dd-STATc is tyrosine phosphorylated, dimerizes, and translocates to the nucleus when cells are exposed to DIF. Surprisingly, however, SH2 domain-phosphotyrosine interaction is not necessary for the DIF-induced nuclear translocation of Dd-STATc. In this respect, Dd-STATc activation resembles several recently described, noncanonical mammalian STAT signaling processes. We show instead that DIF mediates nuclear translocation via sequences located in the divergent, N-terminal half of the Dd-STATc molecule.
Fukuzawa
M
M
School of Life Sciences, University of Dundee, Dundee DD1 5EH, United Kingdom.
Araki
T
T
Adrian
I
I
Williams
J G
JG
D000595:Amino Acid Sequence; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism*; D004023:Dictyostelium / Q000235:genetics*; D019281:Dimerization; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D006588:Hexanones / Q000378:metabolism*; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000502:physiology; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000502:physiology; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism; D050791:STAT Transcription Factors; D015398:Signal Transduction / Q000502:physiology; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism*; D018909:src Homology Domains
D016326:Extracellular Matrix Proteins; D006588:Hexanones; D015800:Protozoan Proteins; D050791:STAT Transcription Factors; C426825:STATc protein, Dictyostelium; D015534:Trans-Activators; C053433:1-((3,5-dichloro)-2,6-dihydroxy-4-methoxyphenyl)-1-hexanone; D014443:Tyrosine