Mapping and functional role of phosphorylation sites in the thyroid transcription factor-1 (TTF-1).
The phosphorylation of thyroid transcription factor-1 (TTF-1), is homeodomain-containing transcription factor that is required for thyroid-specific expression of the thyroglobulin and thyroperoxidase gene promoters, has been studied. Phosphorylation occurs on a maximum of seven serine residues that are distributed in three tryptic peptides. Mutant derivatives of TTF-1, with alanine sites, have been constructed and used to assess the functional relevance of TTF-1 phosphorylation. The DNA binding activity of TTF-1 appears to be phosphorylation-independent, as indicated also by the performance of TTF-1 purified from an overexpressing Escherichia coli strain. Transcriptional activation by TTF-1 could require phosphorylation only in specific cell types since in a co-transfection assay in heterologous cells both wild-type and mutant proteins show a similar transcriptional activity.
Zannini
M
M
Stazione Zoologica A. Dohrn, Napoli, Italy.
Acebron
A
A
De Felice
M
M
Arnone
M I
MI
Martin-Pérez
J
J
Santisteban
P
P
Di Lauro
R
R
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000737:chemistry; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000502:physiology; D005786:Gene Expression Regulation; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry* / Q000502:physiology; D010449:Peptide Mapping; D010750:Phosphoproteins / Q000737:chemistry*; D010766:Phosphorylation; D010768:Phosphoserine / Q000737:chemistry; D051381:Rats; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000737:chemistry* / Q000502:physiology; D014158:Transcription, Genetic
D017931:DNA Primers; D004268:DNA-Binding Proteins; C000614412:NKX2-1 protein, human; C000614416:Nkx2-1 protein, rat; D009687:Nuclear Proteins; D010750:Phosphoproteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D010768:Phosphoserine