TY - JOUR
T1 - Plakoglobin (γ-catenin) has TCF/LEF family-dependent transcriptional activity in β-catenin-deficient cell line
AU - Maeda, Osamu
AU - Usami, Noriyasu
AU - Kondo, Masashi
AU - Takahashi, Masahide
AU - Goto, Hidemi
AU - Shimokata, Kaoru
AU - Kusugami, Kazuo
AU - Sekido, Yoshitaka
PY - 2004/1/29
Y1 - 2004/1/29
N2 - β-Catenin is an essential element for the transcriptional activation of target genes in the Wnt signaling cascade and is also a cell adhesion molecule that couples with cadherins. Although plakoglobin (γ-catenin), a closely related homologue of β-catenin, is also known to be a cell adhesion molecule, its function as a transcriptional factor has not been revealed in detail. Using a human malignant mesothelioma cell line, NCI-H28, in which we have identified a homozygous deletion of the β-catenin gene, we studied whether plakoglobin has a T-cell factor/ lymphocyte enhancer factor (TCF/LEF) family-dependent transcriptional activity. Transaction with the wild-type plakoglobin expression vector induced accumulation of plakoglobin in the nucleus. Immunoprecipitation assay with cotransfection of plakoglobin and either TCF-4 or LEF-1 detected binding of plakoglobin to TCF-4 or LEF-1. Luciferase reporter assay demonstrated transcriptional activity of the wild-type plakoglobin when transfected with TCF/LEF, although plakoglobin showed less activity than β-catenin. Exogenous plakoglobin was also shown to promote entrance of exogenous β-catenin into the nuclei. Furthermore, small interfering RNA directed against plakoglobin suppressed expression of endogenous plakoglobin and its transcriptional activity, suggesting that endogenous plakoglobin has a weak transcriptional activity. These results suggest that plakoglobin can activate the Wnt signaling cascade directly without interaction of β-catenin, and that plakoglobin has multiple functions as a transcriptional activator and a cell adhesion molecule like β-catenin.
AB - β-Catenin is an essential element for the transcriptional activation of target genes in the Wnt signaling cascade and is also a cell adhesion molecule that couples with cadherins. Although plakoglobin (γ-catenin), a closely related homologue of β-catenin, is also known to be a cell adhesion molecule, its function as a transcriptional factor has not been revealed in detail. Using a human malignant mesothelioma cell line, NCI-H28, in which we have identified a homozygous deletion of the β-catenin gene, we studied whether plakoglobin has a T-cell factor/ lymphocyte enhancer factor (TCF/LEF) family-dependent transcriptional activity. Transaction with the wild-type plakoglobin expression vector induced accumulation of plakoglobin in the nucleus. Immunoprecipitation assay with cotransfection of plakoglobin and either TCF-4 or LEF-1 detected binding of plakoglobin to TCF-4 or LEF-1. Luciferase reporter assay demonstrated transcriptional activity of the wild-type plakoglobin when transfected with TCF/LEF, although plakoglobin showed less activity than β-catenin. Exogenous plakoglobin was also shown to promote entrance of exogenous β-catenin into the nuclei. Furthermore, small interfering RNA directed against plakoglobin suppressed expression of endogenous plakoglobin and its transcriptional activity, suggesting that endogenous plakoglobin has a weak transcriptional activity. These results suggest that plakoglobin can activate the Wnt signaling cascade directly without interaction of β-catenin, and that plakoglobin has multiple functions as a transcriptional activator and a cell adhesion molecule like β-catenin.
KW - Malignant mesothelioma
KW - Plakoglobin
KW - Transcriptional activity
KW - Wnt signaling cascade
KW - β-catenin
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U2 - 10.1038/sj.onc.1207254
DO - 10.1038/sj.onc.1207254
M3 - Article
C2 - 14661054
AN - SCOPUS:1342343924
SN - 0950-9232
VL - 23
SP - 964
EP - 972
JO - Oncogene
JF - Oncogene
IS - 4
ER -