Abstract Activating transcription factor 4 (ATF4) is a multifunctional transcription regulatory
protein in the basic leucine zipper superfamily. ATF4 can be expressed in most if not all
mammalian cell types, and it can participate in a variety of cellular responses to specific
environmental stresses, intracellular derangements, or growth factors. Because ATF4 is
involved in a wide range of biological processes, its roles in human health and disease are
not yet fully understood. Much of our current knowledge about ATF4 comes from …