TY - JOUR
T1 - DNA Binding of TEA/ATTS Domain Factors Is Regulated by Protein Kinase C Phosphorylation in Human Choriocarcinoma Cells
AU - Jiang, Shi Wen
AU - Dong, Maoqing
AU - Trujillo, Miguel A.
AU - Miller, Laurence J.
AU - Eberhardt, Norman L.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2001/6/29
Y1 - 2001/6/29
N2 - Transcription enhancer factor 1 (TEF-1) controls the expression of a diverse set of genes. Previous studies implicated protein kinase C (PKC)-mediated signal transduction in modulating TEF function. We demonstrate that in human choriocarcinoma BeWo cells, the PKC activator 12-O-tetradecanoyl phorbol 13-acetate and PKC inhibitor bisindolylmaleimide reciprocally down- and up-regulate, respectively, TEF-mediated GGAATG core enhancer activity. In vitro TEF-1 phosphorylation with several PKC isozymes and phosphoamino acid analysis confirmed that TEF-1 is a potential PKC substrate. TEF-1·DNA complexes formed by BeWo nuclear extracts are supershifted by phosphoserine- and phosphothreonine- but not phosphotyrosine-specific antibodies, indicating that TEF-1 is phosphorylated in vivo at serine and threonine residues. The TEF-1 phosphorylation domain was localized to the third α-helix of the DNA binding domain and adjacent hinge region by phosphopeptide analysis. TEF-1 phosphorylation significantly reduced its DNA binding activity both in vitro and in vivo, providing a possible mechanism for the inhibitory action of PKC. Finally, BeWo cells contained abundant levels of γ and δ PKC isoforms, and their overexpression resulted in even greater inhibition of GGAATG core enhancer activity after 12-O-tetradecanoyl phorbol 13-acetate treatment. These data strongly suggest that PKC-mediated phosphorylation is a key factor controlling TEF function.
AB - Transcription enhancer factor 1 (TEF-1) controls the expression of a diverse set of genes. Previous studies implicated protein kinase C (PKC)-mediated signal transduction in modulating TEF function. We demonstrate that in human choriocarcinoma BeWo cells, the PKC activator 12-O-tetradecanoyl phorbol 13-acetate and PKC inhibitor bisindolylmaleimide reciprocally down- and up-regulate, respectively, TEF-mediated GGAATG core enhancer activity. In vitro TEF-1 phosphorylation with several PKC isozymes and phosphoamino acid analysis confirmed that TEF-1 is a potential PKC substrate. TEF-1·DNA complexes formed by BeWo nuclear extracts are supershifted by phosphoserine- and phosphothreonine- but not phosphotyrosine-specific antibodies, indicating that TEF-1 is phosphorylated in vivo at serine and threonine residues. The TEF-1 phosphorylation domain was localized to the third α-helix of the DNA binding domain and adjacent hinge region by phosphopeptide analysis. TEF-1 phosphorylation significantly reduced its DNA binding activity both in vitro and in vivo, providing a possible mechanism for the inhibitory action of PKC. Finally, BeWo cells contained abundant levels of γ and δ PKC isoforms, and their overexpression resulted in even greater inhibition of GGAATG core enhancer activity after 12-O-tetradecanoyl phorbol 13-acetate treatment. These data strongly suggest that PKC-mediated phosphorylation is a key factor controlling TEF function.
UR - http://www.scopus.com/inward/record.url?scp=0035968203&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035968203&partnerID=8YFLogxK
U2 - 10.1074/jbc.M010934200
DO - 10.1074/jbc.M010934200
M3 - Article
C2 - 11313339
AN - SCOPUS:0035968203
SN - 0021-9258
VL - 276
SP - 23464
EP - 23470
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 26
ER -