Published online 12 May 2006
Article |
GAS41 interacts with transcription factor AP-2ß and stimulates AP-2ß-mediated transactivation
1 Key Laboratory of Protein Chemistry and Developmental Biology of State Education Ministry of China, College of Life Science, Hunan Normal University Changsha, Hunan 410081, China 2 Model Organism Division, E-Institutes of Shanghai Universities, Shanghai Second Medical University Shanghai 200025, China
*To whom correspondence should be addressed. Tel/Fax: +86 731 8872792; Email: zhangjian{at}hunnu.edu.cn
Received April 12, 2006. Revised April 13, 2006. Accepted April 13, 2006.
Transcription factor AP-2 regulates transcription of a number of genes involving mammalian development, differentiation and carcinogenesis. Recent studies have shown that interaction partners can modulate the transcriptional activity of AP-2 over the downstream targets. In this study, we reported the identification of GAS41 as an interaction partner of AP-2ß. We documented the interaction both in vivo by co-immunoprecipitation as well as in vitro through glutathione S-transferase (GST) pull-down assays. We also showed that the two proteins are co-localized in the nuclei of mammalian cells. We further mapped the interaction domains between the two proteins to the C-termini of both AP-2ß and GAS41, respectively. Furthermore, we have identified three critical residues of GAS41 that are important for the interaction between the two proteins. In addition, by transient co-expression experiments using reporter containing three AP-2 consensus binding sites in the promoter region, we found that GAS41 stimulates the transcriptional activity of AP-2ß over the reporter. Finally, electrophoretic mobility shift assay (EMSA) suggested that GAS41 enhances the DNA-binding activity of AP-2ß. Our data provide evidence for a novel cellular function of GAS41 as a transcriptional co-activator for AP-2ß.