title: Evolution of the family of intracellular lipid binding proteins in vertebrates.
abstract: Members of the family of intracellular lipid binding proteins (iLBPs) have been implicated in cytoplasmic transport of lipophilic ligands, such as long-chain fatty acids and retinoids. iLBPs are low molecular mass proteins (14-16 kDa) sharing a common structural fold. The iLBP family likely arose through duplication and diversification of an ancestral iLBP gene. Phylogenetic analysis undertaken in the present study indicates that the ancestral iLBP gene arose after divergence of animals from fungi and plants. The first gene duplication was dated around 930 millions of years ago, and subsequent duplications in the succeeding 550 millions of years gave rise to the 16 iLBP types currently recognized in vertebrates. Four clusters of proteins, each binding a characteristic range of ligands, are evident from the phylogenetic tree. Evolution of different binding properties probably allowed cytoplasmic trafficking of distinct ligands. It is speculated that recruitment of an iLBP during evolution of animals enabled the mitochondrial oxidation of long-chain fatty acids.
authors.affiliation: Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands. f.g.schaap@amc.uva.nl
authors.forename: Frank G
authors.initials: FG
authors.lastname: Schaap
authors.forename: Ger J
authors.initials: GJ
authors.lastname: van der Vusse
authors.forename: Jan F C
authors.initials: JF
authors.lastname: Glatz
mesh_terms: D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000145:classification* / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D020440:Gene Duplication; D006801:Humans; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins; D010802:Phylogeny; D025521:Tumor Suppressor Proteins; D014714:Vertebrates / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; C107608:FABP7 protein, human; D000071438:Fatty Acid-Binding Protein 7; D050556:Fatty Acid-Binding Proteins; D009363:Neoplasm Proteins; D025521:Tumor Suppressor Proteins