<p>Transthyretin (prealbumin) is a thyroid hormone-binding protein that seems to transport thyroxine (T4) from the bloodstream to the brain. It is a protein of about 130 amino acids that assembles as a homotetramer and forms an internal channel that binds thyroxine. In humans, transthyretin is mainly synthesized in the brain choroid plexus; variants of the protein are associated with distinct forms of amyloidosis. </p><p>The sequence of transthyretin is highly conserved in vertebrates. A number of uncharacterised proteins also belong to this family: </p><ul><li> Escherichia coli hypothetical protein YedX. </li><li> Bacillus subtilis hypothetical protein YunM. </li><li> Caenorhabditis elegans hypothetical protein R09H10.3. </li><li> Caenorhabditis elegans hypothetical protein ZK697.8. </li></ul><p>The signature pattern in this entry is located at the C terminus. </p> Transthyretin, conserved site