Abstract
We have previously shown that modification of Tcf-4, a transcription factor in the Wnt pathway, with SUMO by PIASy, a SUMO E3 ligase, enhances its transcriptional activity. Since PIASy itself was also modified with SUMO-1, we studied the role of sumoylation of PIASy in the regulation of Tcf-4. Lys(35) was found to be a sumoylation site of PIASy. PIASy(K35R), in which Lys(35) was mutated to Arg, did not enhance sumoylation of Tcf-4, although this PIASy mutant did not lose the ligase activity of sumoylation for other proteins. Wild-type PIASy and PIASy(K35R) showed a distinct distribution in the nucleus, although both were colocalized with Tcf-4. Promyelocytic leukemia protein, which is involved in transcriptional regulation, was associated with PIASy(K35R) more frequently than wild-type PIASy in the nucleus. PIASy(K35R) could not stimulate the transcriptional activity of Tcf-4 under the conditions in which wild-type PIASy enhanced it. Conjugation of SUMO-1 to the amino terminus of PIASy(K35R) neither enhanced sumoylation of Tcf-4 nor stimulated the transcriptional activity of Tcf-4. These results suggest that sumoylation of Lys(35) in PIASy determines the nuclear localization of PIASy and that it is necessary for PIASy-dependent sumoylation and transcriptional activation of Tcf-4.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Amino Acid Substitution / genetics
-
Animals
-
Arginine / metabolism
-
Cell Line
-
Cell Nucleus / chemistry
-
DNA-Binding Proteins / analysis
-
DNA-Binding Proteins / metabolism*
-
Humans
-
Intracellular Signaling Peptides and Proteins / analysis
-
Intracellular Signaling Peptides and Proteins / genetics
-
Intracellular Signaling Peptides and Proteins / metabolism*
-
Lysine / metabolism
-
Mutation / genetics
-
Neoplasm Proteins / metabolism
-
Nuclear Proteins / analysis
-
Nuclear Proteins / genetics
-
Nuclear Proteins / metabolism*
-
Poly-ADP-Ribose Binding Proteins
-
Promyelocytic Leukemia Protein
-
Protein Inhibitors of Activated STAT
-
Recombinant Fusion Proteins / metabolism
-
SUMO-1 Protein / physiology*
-
TCF Transcription Factors
-
Transcription Factor 7-Like 2 Protein
-
Transcription Factors / analysis
-
Transcription Factors / metabolism*
-
Transcription, Genetic / genetics
-
Transcription, Genetic / physiology
-
Tumor Suppressor Proteins
-
Ubiquitin-Protein Ligases / physiology*
Substances
-
DNA-Binding Proteins
-
Intracellular Signaling Peptides and Proteins
-
Neoplasm Proteins
-
Nuclear Proteins
-
PIAS4 protein, human
-
Poly-ADP-Ribose Binding Proteins
-
Promyelocytic Leukemia Protein
-
Protein Inhibitors of Activated STAT
-
Recombinant Fusion Proteins
-
SUMO-1 Protein
-
TCF Transcription Factors
-
TCF7L2 protein, human
-
Transcription Factor 7-Like 2 Protein
-
Transcription Factors
-
Tumor Suppressor Proteins
-
PML protein, human
-
Arginine
-
Ubiquitin-Protein Ligases
-
Lysine