Transcription factor that binds the cAMP response element (CRE) (consensus: 5'-GTGACGT[AC][AG]-3') and acts both as a regulator of normal metabolic and redox processes, and as a master transcription factor during the integrated stress response (ISR) . Binds to asymmetric CRE's as a heterodimer and to palindromic CRE's as a homodimer .