title: Ancestry and progeny of nutrient amino acid transporters.
abstract: The biosynthesis of structural and signaling molecules depends on intracellular concentrations of essential amino acids, which are maintained by a specific system of plasma membrane transporters. We identify a unique population of nutrient amino acid transporters (NATs) within the sodium-neurotransmitter symporter family and have characterized a member of the NAT subfamily from the larval midgut of the Yellow Fever vector mosquito, Aedes aegypti (aeAAT1, AAR08269), which primarily supplies phenylalanine, an essential substrate for the synthesis of neuronal and cuticular catecholamines. Further analysis suggests that NATs constitute a comprehensive transport metabolon for the epithelial uptake and redistribution of essential amino acids including precursors of several neurotransmitters. In contrast to the highly conserved subfamily of orthologous neurotransmitter transporters, lineage-specific, paralogous NATs undergo rapid gene multiplication/substitution that enables a high degree of evolutionary plasticity of nutrient amino acid uptake mechanisms and facilitates environmental and nutrient adaptations of organisms. These findings provide a unique model for understanding the molecular mechanisms, physiology, and evolution of amino acid and neurotransmitter transport systems and imply that monoamine and GABA transporters evolved by selection and conservation of earlier neuronal NATs.
authors.affiliation: The Whitney Laboratory for Marine Bioscience, University of Florida, 9505 Ocean Shore Boulevard, St. Augustine, FL 32080, USA. boudko@whitney.ufl.edu
authors.forename: Dmitri Y
authors.initials: DY
authors.lastname: Boudko
authors.forename: Andrea B
authors.initials: AB
authors.lastname: Kohn
authors.forename: Ella A
authors.initials: EA
authors.lastname: Meleshkevitch
authors.forename: Michelle K
authors.initials: MK
authors.lastname: Dasher
authors.forename: Theresa J
authors.initials: TJ
authors.lastname: Seron
authors.forename: Bruce R
authors.initials: BR
authors.lastname: Stevens
authors.forename: William R
authors.initials: WR
authors.lastname: Harvey
mesh_terms: D000330:Aedes / Q000254:growth & development; D000595:Amino Acid Sequence; D026905:Amino Acid Transport Systems / Q000145:classification / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers; D005260:Female; D017403:In Situ Hybridization; D007814:Larva; D008564:Membrane Potentials / Q000502:physiology; D008969:Molecular Sequence Data; D009865:Oocytes / Q000502:physiology; D018408:Patch-Clamp Techniques; D010802:Phylogeny; D015183:Restriction Mapping; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic; D014982:Xenopus laevis
chemical_list: D026905:Amino Acid Transport Systems; D017931:DNA Primers