EIF2AK3 and brain disorder: The ISRIB molecule, which is a very promising drug intensively investigated in malignant brain conditions and age-related memory decline [58, 59], as well as in some metastatic tumors [16, 42–44, 60, 61], in contrast to PERK inhibitors, acts downstream of phosphorylated eIF2α and directly inhibits the executive part of the ISR [37, 42, 44].