Translocator protein

Translocator protein (TSPO) is an 18.8 kDa mitochondrial membrane protein encoded by the TSPO gene (UniProt: P30536). It functions in the transport of cholesterol across mitochondrial membranes and may modulate lipid metabolism; it can also bind protoporphyrin IX and benzodiazepines, though its precise physiological role remains debated (UniProt: P30536).

TSPO is localized to mitochondria and plays roles in porphyrin and steroid metabolism. No disease associations are explicitly documented in UniProt for this protein, though its mitochondrial function suggests relevance to cellular bioenergetics.

TSPO shows increased abundance in Alzheimer's disease brain tissue, with a mean log2 fold-change of +0.64 relative to age-matched controls (Chaparral AD proteomics). This upregulation was detected across a human post-mortem study using TMT-labeled quantitative mass spectrometry across multiple subcellular fractions, suggesting potential involvement in compensatory mitochondrial lipid metabolism or immune-related microglial activation in AD pathology.