Transthyretin (TTR)

Transthyretin (TTR), formerly known as thyroxine-binding prealbumin, is a tetrameric protein transporting hormones in the plasma and brain. It forms a complex with retinol-binding protein (RBP), which facilitates the transport of thyroid hormones and vitamin A in the blood and cerebrospinal fluid. TTR is a positive indicator of nutrition status and is negatively correlated with inflammation. TTR is a neuroprotective and oxidative-stress-suppressing factor. The TTR structure is destabilized by mutations, oxidative modifications, aging, proteolysis, and metal cations, including Ca²⁺. Destabilized TTR molecules form amyloid deposits, resulting in senile and familial amyloidopathies.