CISD1 is a mitochondrial iron-sulfur cluster-binding protein with dual catalytic and regulatory functions. As an L-cysteine transaminase, CISD1 catalyzes reversible transamination of L-cysteine to form 2-oxo-3-sulfanylpropanoate and L-glutamate using pyridoxal 5'-phosphate as a cofactor 1. Beyond catalysis, CISD1 functions as a redox sensor that transfers [2Fe-2S] clusters to apo-acceptor proteins in its oxidized state, regulating mitochondrial iron-sulfur cluster assembly and iron trafficking during oxidative stress 234. CISD1 holds substantial clinical significance across multiple diseases. In Parkinson's disease, CISD1 accumulation blocks mitophagy and impairs autophagy flux; genetic or pharmacological inhibition of CISD1/2 rescues neurodegenerative phenotypes in PINK1/parkin mutant models 56. In ferroptosis-related pathologies, CISD1 functions as a ferroptosis suppressor—its downregulation promotes ferroptosis in alcoholic liver disease 7, endometrial cancer 8, and atherosclerosis 9. Conversely, CISD1 overexpression associates with poor prognosis in gastric cancer 10. In COPD, smoke-induced CISD1 reduction in macrophages promotes M1 polarization and mitochondrial dysfunction 11. These findings position CISD1 as a critical node regulating mitochondrial homeostasis, ferroptosis, and neuroinflammation, making it a promising therapeutic target across neurodegenerative, metabolic, and malignant diseases.