title: Novel insights into the transport mechanism of the human amino acid transporter LAT1 (SLC7A5). Probing critical residues for substrate translocation.
abstract: LAT1 (SLC7A5) is the transport competent unit of the heterodimer formed with the glycoprotein CD98 (SLC3A2). It catalyzes antiport of His and some neutral amino acids such as Ile, Leu, Val, Cys, Met, Gln and Phe thus being involved in amino acid metabolism. Interestingly, LAT1 is over-expressed in many human cancers that are characterized by increased demand of amino acids. Therefore LAT1 was recently acknowledged as a novel target for cancer therapy. However, knowledge on molecular mechanism of LAT1 transport is still scarce.
  
  
  
  Combined approaches of bioinformatics, site-directed mutagenesis, chemical modification, and transport assay in proteoliposomes, have been adopted to unravel dark sides of human LAT1 structure/function relationships.
  
  
  
  It has been demonstrated that residues F252, S342, C335 are crucial for substrate recognition and C407 plays a minor role. C335 and C407 cannot be targeted by SH reagents. The transporter has a preferential dimeric structure and catalyzes an antiport reaction which follows a simultaneous random mechanism.
  
  
  
  Critical residues of the substrate binding site of LAT1 have been probed. This site is not freely accessible by molecules other than substrate. Similarly to LeuT, K+has some regulatory properties on LAT1.
  
  
  
  The collected data represent a solid basis for deciphering molecular mechanism underlying LAT1 function.
authors.affiliation: Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy.
authors.forename: Lara
authors.initials: L
authors.lastname: Napolitano
authors.affiliation: Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Galluccio
authors.affiliation: Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy.
authors.forename: Mariafrancesca
authors.initials: M
authors.lastname: Scalise
authors.affiliation: Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Parravicini
authors.affiliation: Dipartimento di Scienze Farmacologiche e Biomolecolari e Dipartimento di Scienze Biomediche e Cliniche "L. Sacco", Università degli Studi di Milano, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Palazzolo
authors.affiliation: Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Italy.
authors.forename: Ivano
authors.initials: I
authors.lastname: Eberini
authors.affiliation: Department DiBEST (Biologia, Ecologia, Scienze della Terra) Unit of Biochemistry and Molecular Biotechnology, University of Calabria, Via P. Bucci 4C, 87036 Arcavacata di Rende, Italy. Electronic address: cesare.indiveri@unical.it.
authors.forename: Cesare
authors.initials: C
authors.lastname: Indiveri
mesh_terms: D000595:Amino Acid Sequence; D026905:Amino Acid Transport Systems / Q000378:metabolism*; D000596:Amino Acids / Q000378:metabolism*; D006801:Humans; D017136:Ion Transport / Q000502:physiology; D027283:Large Neutral Amino Acid-Transporter 1 / Q000378:metabolism*; D021381:Protein Transport / Q000502:physiology*; D011510:Proteolipids / Q000378:metabolism; D016415:Sequence Alignment
chemical_list: D026905:Amino Acid Transport Systems; D000596:Amino Acids; D027283:Large Neutral Amino Acid-Transporter 1; D011510:Proteolipids; C020485:proteoliposomes
keywords: Docking; Liposome; Membrane transporter reconstitution; Recombinant protein expression; Site-directed mutagenesis