title: Structural bases for the interaction and stabilization of the human amino acid transporter LAT2 with its ancillary protein 4F2hc.
abstract: Heteromeric amino acid transporters (HATs) are the unique example, known in all kingdoms of life, of solute transporters composed of two subunits linked by a conserved disulfide bridge. In metazoans, the heavy subunit is responsible for the trafficking of the heterodimer to the plasma membrane, and the light subunit is the transporter. HATs are involved in human pathologies such as amino acidurias, tumor growth and invasion, viral infection and cocaine addiction. However structural information about interactions between the heavy and light subunits of HATs is scarce. In this work, transmission electron microscopy and single-particle analysis of purified human 4F2hc/L-type amino acid transporter 2 (LAT2) heterodimers overexpressed in the yeast Pichia pastoris, together with docking analysis and crosslinking experiments, reveal that the extracellular domain of 4F2hc interacts with LAT2, almost completely covering the extracellular face of the transporter. 4F2hc increases the stability of the light subunit LAT2 in detergent-solubilized Pichia membranes, allowing functional reconstitution of the heterodimer into proteoliposomes. Moreover, the extracellular domain of 4F2hc suffices to stabilize solubilized LAT2. The interaction of 4F2hc with LAT2 gives insights into the structural bases for light subunit recognition and the stabilizing role of the ancillary protein in HATs.
authors: Institute for Research in Biomedicine (IRB Barcelona), E-08028 Barcelona, Spain.
authors: Albert
authors: A
authors: Rosell
authors: Marcel
authors: M
authors: Meury
authors: Elena
authors: E
authors: Álvarez-Marimon
authors: Meritxell
authors: M
authors: Costa
authors: Laura
authors: L
authors: Pérez-Cano
authors: Antonio
authors: A
authors: Zorzano
authors: Juan
authors: J
authors: Fernández-Recio
authors: Manuel
authors: M
authors: Palacín
authors: Dimitrios
authors: D
authors: Fotiadis
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000378:metabolism*; D015153:Blotting, Western; D002846:Chromatography, Affinity; D002850:Chromatography, Gel; D027282:Fusion Regulatory Protein 1, Heavy Chain / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D010843:Pichia; D011485:Protein Binding; D011487:Protein Conformation
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D027282:Fusion Regulatory Protein 1, Heavy Chain; C419196:LAT2 protein, human; C545989:SLC3A2 protein, human
keywords: 4F2hc ectodomain; CD98hc