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The A20‐binding protein ABIN‐2 exerts unexpected function in mediating transcriptional coactivation
Author(s) -
Chien Chia-Yi,
Liu Wei-Kuang,
Chou Chen-Kung,
Su Jin-Yuan
Publication year - 2003
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(03)00401-0
Subject(s) - coactivator , microbiology and biotechnology , chromatin , reporter gene , transcription factor , chemistry , biology , gene , gene expression , biochemistry
The human ABIN‐2 was originally identified as an A20‐associating cytosolic protein to block NF‐κB activation induced by various stimuli. Here we report that ABIN‐2 has the potential to enter the nucleus and plays a role in mediating transcriptional activation in both yeast and mammalian cells. The Gal4BD–ABIN‐2 fusion protein is able to drive the expression of the GAL4 ‐responsive reporter gene in yeast efficiently without the need of the Gal4p activation domain, suggesting that ABIN‐2 functions as a transcriptional coactivator and facilitates transcription in yeast. In contrast to the activity in yeast, however, only the C‐terminal fragment of ABIN‐2 exerts the transactivating activity in mammalian cells but not the full‐length ABIN‐2 protein. This observation has led to the identification of the N‐terminal 195 amino acids of ABIN‐2 as a regulatory domain, which retains the full‐length ABIN‐2 in the cytoplasm of mammalian cells and thus cannot transactivate. We have also found that BAF60a, a component of chromatin‐remodeling complex, interacts with ABIN‐2 by the yeast two‐hybrid analysis. Together, our results suggest that the nuclear ABIN‐2 defines a novel transcriptional coactivator and acts presumably by recruiting a chromatin‐remodeling complex to the site of the target gene.