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Mammalian transcription factor LSF is a target of ERK signaling
Author(s) -
Pagon Zrinka,
Volker Janet,
Cooper Geoffrey M.,
Hansen Ulla
Publication year - 2003
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.10549
Subject(s) - mapk/erk pathway , phosphorylation , microbiology and biotechnology , transcription factor , biology , 3t3 cells , chemistry , cell culture , gene , biochemistry , transfection , genetics
LSF is a mammalian transcription factor that is rapidly and quantitatively phosphorylated upon growth induction of resting, peripheral human T cells, as assayed by a reduction in its electrophoretic mobility. The DNA‐binding activity of LSF in primary T cells is greatly increased after this phosphorylation event (Volker et al. [1997]: Genes Dev 11:1435–1446). We demonstrate here that LSF is also rapidly and quantitatively phosphorylated upon growth induction in NIH 3T3 cells, although its DNA‐binding activity is not significantly altered. Three lines of experimentation established that ERK is responsible for phosphorylating LSF upon growth induction in both cell types. First, phosphorylation of LSF by ERK is sufficient to cause the reduced electrophoretic mobility of LSF. Second, the amount of ERK activity correlates with the extent of LSF phosphorylation in both primary human T cells and NIH 3T3 cells. Finally, specific inhibitors of the Ras/Raf/MEK/ERK pathway inhibit LSF modification in vivo. This phosphorylation by ERK is not sufficient for activation of LSF DNA–binding activity, as evidenced both in vitro and in mouse fibroblasts. Nonetheless, activation of ERK is a prerequisite for the substantial increase in LSF DNA–binding activity upon activation of resting T cells, indicating that ERK phosphorylation is necessary but not sufficient for activation of LSF in this cell type. J. Cell. Biochem. 89: 733–746, 2003. © 2003 Wiley‐Liss, Inc.