CHOP/GADD153 plays a critical role in endoplasmic reticulum (ER) stress-mediated apoptosis and is involved in various diseases such as diabetes, brain ischemia, and neurodegenerative disorders. ER stress occurs when the ER is unable to properly fold proteins, leading to the accumulation of misfolded proteins. In response, the ER activates several signaling pathways, including translational attenuation, upregulation of ER chaperones, and degradation of misfolded proteins. However, severe ER stress can trigger apoptosis through the activation of CHOP, which is a transcription factor that promotes apoptosis by inducing the expression of pro-apoptotic genes. CHOP is a 29 kDa protein with an N-terminal transcriptional activation domain and a C-terminal basic-leucine zipper (bZIP) domain. It is induced by various stressors, including ER stress, nutrient deprivation, and DNA damage. CHOP is primarily regulated at the transcriptional level and is induced by three main signaling pathways: PERK, ATF6, and Ire1. These pathways lead to the activation of transcription factors such as ATF4, pATF6, and XBP-1, which in turn induce the expression of CHOP. CHOP-mediated apoptosis is involved in the pathogenesis of several diseases. In diabetes, ER stress in pancreatic β-cells leads to apoptosis, which is a major cause of β-cell loss. CHOP induction in β-cells contributes to this process. In brain ischemia, ER stress and CHOP induction are associated with neuronal cell death. In neurodegenerative diseases, protein misfolding and ER stress are implicated in the pathogenesis, and CHOP may play a role in the progression of these diseases. CHOP is also involved in the regulation of cell survival and death. It can interact with other transcription factors and modulate the expression of genes involved in apoptosis. The role of CHOP in disease development suggests that targeting CHOP could be a potential therapeutic strategy for diseases associated with ER stress. However, the exact mechanisms by which CHOP induces apoptosis and its role in disease progression are still being studied.CHOP/GADD153 plays a critical role in endoplasmic reticulum (ER) stress-mediated apoptosis and is involved in various diseases such as diabetes, brain ischemia, and neurodegenerative disorders. ER stress occurs when the ER is unable to properly fold proteins, leading to the accumulation of misfolded proteins. In response, the ER activates several signaling pathways, including translational attenuation, upregulation of ER chaperones, and degradation of misfolded proteins. However, severe ER stress can trigger apoptosis through the activation of CHOP, which is a transcription factor that promotes apoptosis by inducing the expression of pro-apoptotic genes. CHOP is a 29 kDa protein with an N-terminal transcriptional activation domain and a C-terminal basic-leucine zipper (bZIP) domain. It is induced by various stressors, including ER stress, nutrient deprivation, and DNA damage. CHOP is primarily regulated at the transcriptional level and is induced by three main signaling pathways: PERK, ATF6, and Ire1. These pathways lead to the activation of transcription factors such as ATF4, pATF6, and XBP-1, which in turn induce the expression of CHOP. CHOP-mediated apoptosis is involved in the pathogenesis of several diseases. In diabetes, ER stress in pancreatic β-cells leads to apoptosis, which is a major cause of β-cell loss. CHOP induction in β-cells contributes to this process. In brain ischemia, ER stress and CHOP induction are associated with neuronal cell death. In neurodegenerative diseases, protein misfolding and ER stress are implicated in the pathogenesis, and CHOP may play a role in the progression of these diseases. CHOP is also involved in the regulation of cell survival and death. It can interact with other transcription factors and modulate the expression of genes involved in apoptosis. The role of CHOP in disease development suggests that targeting CHOP could be a potential therapeutic strategy for diseases associated with ER stress. However, the exact mechanisms by which CHOP induces apoptosis and its role in disease progression are still being studied.