A number of proteins related to the homotetrameric trans-port protein transthyretin (TTR) forms a highly conserved protein family, whichwe present in an integrated analysis of data from different sources combined with an initial bio-chemical of the transthyretin-relatedprotein (TRP) canbe found inawide rangeof species including bacteria, plants and animals, whereas transthyre-tinshave so faronlybeen identified invertebrates.