Translocator protein (TSPO), also known as the 18-kDa translocator protein, is a protein located in the outer mitochondrial membrane, composed of five transmembrane domains. It is widely expressed in various tissues, particularly in the adrenal glands, liver, and central nervous system. TSPO is involved in regulating mitochondrial function, cell apoptosis, steroid hormone synthesis, and inflammatory responses. By interacting with other mitochondrial proteins such as VDAC and ANT, it influences cellular metabolism and signaling. In diseased states, such as neurodegenerative diseases, cancer, and cardiovascular diseases, the expression levels of TSPO often change. The specific expression and mutations of the TSPO gene are associated with the development of various diseases.