Abstract LB-333: A CREBZF/Zhangfei isoform activates CHOP and promotes apoptosis during prolonged endoplasmic reticulum stress

Abstract The basic leucine zipper transcription factor CREBZF (Zhangfei or ZF) was identified through its interaction with Herpes Simplex Virus-1 related cellular protein HCF-1, and has been implicated in cellular stress responses through its interaction with other proteins, such as CREB3/Luman and ATF4. Here we investigated the production of four CREBZF isoforms, which arise from translational initiation of a downstream AUG at codon 83 and mRNA alternative splicing that adds an IFFFR pentapeptidyl tail to the C-terminus. We found that in addition to transcriptional induction, the short-tailed CREBZF (stZF) isoform was specifically induced by prolonged ER stress treatment and amino acid deprivation. This stZF isoform is a potent transcriptional activator of the pro-apoptotic protein CHOP. Overexpression of stZF activates transcription of CHOP through a CCAAT enhancer binding protein (C/EBP)-ATF site, and promotes apoptosis. We propose that 1) CREBZF is a key component of the integrated stress response; 2) stZF is tightly regulated and induced primarily under prolonged cellular stress, and is essential for the role of CREBZF in inducing CHOP and promoting cell death. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-333.