Abstract
The transcription factor ATF-2 (also called CRE-BP1), whose DNA-binding domain consists of a basic amino acid cluster and a leucine zipper (b-ZIP) region, binds to the cAMP response element as a homodimer or as a heterodimer with c-Jun. The amino-terminal region of ATF-2 containing the transcriptional activation domain is phosphorylated by stress-activated kinases, which leads to activation of ATF-2. We report here that CBP, which was originally identified as a co-activator of CREB, directly binds to the b-ZIP region of ATF-2 via a Cys/His-rich region termed C/H2, and potentiates trans-activation by ATF-2. The b-ZIP region of ATF-2 was previously shown to interact with the amino-terminal region intramolecularly and to inhibit trans-activating capacity. The binding of CBP to the b-ZIP region abrogates this intramolecular interaction. The adenovirus 13S E1A protein which binds to the b-ZIP region of ATF-2 also inhibited this intramolecular interaction, suggesting that both CBP and 13S E1A share a similar function as positive regulators of ATF-2. We found that the b-ZIP regions of c-Jun and CREB also interact with the C/H2 domain of CBP, suggesting that CBP acts as a regulator for a group of b-ZIP-containing proteins. These results shed light on a novel aspect of CBP function as a regulator for a group of b-ZIP-containing proteins.
Highlights
A number of transcription factors of the ATF/CREB family have been identified
The two amino-truncated mutants, NT253 and NT341, lacking the amino-terminal 253 and 341 amino acids, respectively, bound to CBP as efficiently as the wild type. These results indicate that CBP binds to the carboxyl-terminal 164-amino acid region containing the b-ZIP region
These results indicate that CBP binds to the b-ZIP region of ATF-2 and that the region downstream from the b-ZIP region enhances the interaction with CBP
Summary
A number of transcription factors of the ATF/CREB family have been identified. We found that the b-ZIP regions of c-Jun and CREB interact with the C/H2 domain of CBP, suggesting that CBP acts as a regulator for a group of b-ZIP-containing proteins. The plasmid encoding the VP16 fusion protein containing the carboxyl-terminal region of ATF-2 (amino acids 291–505), CREB (amino acids 191–341), or c-Jun (amino acids 201–334) joined to the VP16 activation domain was constructed .
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
