Translational activator of cytochrome c oxidase 1

TACO1 (translational activator of cytochrome c oxidase 1) is a 297-amino acid protein that functions as a translational activator for mitochondrially-encoded cytochrome c oxidase 1 (UniProt: Q9BSH4). It plays a critical role in mitochondrial oxidative phosphorylation by regulating synthesis of a core component of respiratory complex IV.

Mutations in TACO1 cause mitochondrial complex IV deficiency, nuclear type 8 (MC4DN8), a rare autosomal recessive disorder characterized by cognitive dysfunction, dystonia, visual impairment, white matter abnormalities, and elevated serum lactate. These clinical features highlight the importance of TACO1 in neurological function and cellular energy metabolism.

In Alzheimer's disease, TACO1 is significantly upregulated in post-mortem AD brain tissue compared to age-matched controls (mean log2 fold-change: 0.433; Chaparral AD proteomics). This elevation suggests altered mitochondrial bioenergetic responses in AD pathology, potentially reflecting compensatory mechanisms or mitochondrial stress associated with neurodegeneration.