ATF4 and chronic kidney disease: ER stress was triggered by Ang II in podocytes of CKD, manifested by elevated levels of ER stress-related proteins, including glucose-regulated protein 78, activating transcription factor 4 (ATF4), eukaryotic initiation factor-2α (eIF2α), and C/EBP homologous protein (CHOP) (Yu et al., 2020).