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Coactivator ASC‐2 mediates heat shock factor 1‐mediated transactivation dependent on heat shock
Author(s) -
Hong SunHwa,
Kim Sun Hee,
Heo Mi Ae,
Choi Yoon Ha,
Park Min Jung,
Yoo Mi Ae,
Kim Han Do,
Kang Ho Sung,
Cheong JaeHun
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(04)00028-6
Subject(s) - hsf1 , transactivation , heat shock factor , coactivator , heat shock , transcription factor , heat shock protein , microbiology and biotechnology , chemistry , transcription (linguistics) , biology , hsp70 , biochemistry , gene , linguistics , philosophy
Upon exposure to elevated temperatures, mammalian cells increase the expression of the heat shock proteins (HSP) through activation of the heat shock factor 1 (HSF1). Since most transcription factors require coactivators for efficient transcriptional activity, we tried to identify the coactivator(s) that interacts with and modulates the activities of HSF1. In vitro glutathione S‐transferase (GST) pull‐down assay revealed that HSF1 strongly interacts with activating signal cointegrator (ASC)‐2 and weakly with cyclic adenosine monophosphate responsive element binding protein (CBP). We also show that cotransfection of ASC‐2, but not CBP, potentiates HSF1‐mediated transactivation based on its cognate element (heat shock element, HSE) linked to luciferase reporter. The molecular interaction of HSF1 and ASC‐2 was stimulated by heat shock in cells and the overexpression of HSF1‐interacting domain of ASC‐2 inhibited the specific induced protein association and HSF1‐mediated transactivation. Taking these results together, we suggest that ASC‐2 in a novel coactivator for HSF1 and heat shock stress may contribute the strong active transcription complex through sequential recruitment of HSF1 and ASC‐2.