Molecular Interplay of ISG15/ISGylation in Neuropathologies

ISG15 is a 15 kDa ubiquitin-like protein that covalently associates with its target proteins by a sequential enzymatic process known as ISGylation. Research on protein ISGylation has increased in recent years, and some studies have suggested that ISG15 is involved in neuroprotection and neurodegeneration mechanisms. This review outlines the current state of research on the implications of ISG15/ISGylation in other neuropathies such as malignant tumors, ataxia telangiectasia, ischemia, depression, and neurodegenerative diseases such as Alzheimer's, Parkinson's diseases, multiple sclerosis, and amyotrophic lateral sclerosis. Based on the studies reported to date, ISG15/ ISGylation promotes the progression of brain tumors such as glioblastoma. Moreover, ISG15/ ISGylation seems to play a dual role in neuropathies, demonstrating a neuroprotective effect when there is acute brain damage, but ISG15/ISGylation is associated with reduced neuroprotection when there is chronic damage, such as in neurodegenerative diseases.