MOLECULAR EVOLUTION OF THE MULTIGENE FAMILY OF INTRACELLULAR LIPID-BINDING PROTEINS

The intracellular lipid-binding proteins are a group of homologous pro teins which bind and facilitate the transport of fatty acids, bile aci ds and retinoids. The evolutionary relationship of 51 family members f rom vertebrates and invertebrates was analyzed. The inferred phylogeny implies the occurrence of at least 14 gene duplications and contains five regions where the branching order is statistically non-significan t-this uncertainty explaining most inconsistencies between previous ph ylogenetic analyses. The phylogeny also suggests that the intestinal f atty acid-binding protein and the liver fatty acid-binding protein/ile al lipid-binding protein subfamilies diverged from the other subfamili es before the vertebrate-invertebrate split. Finally, results presente d herein indicate that the putative fatty acid-binding domain of NMDA receptor 1 is unlikey to be a member of this family.