title: Polarized transport of MHC class II molecules in Madin-Darby canine kidney cells is directed by a leucine-based signal in the cytoplasmic tail of the beta-chain.
abstract: MHC class II molecules are found on the basolateral plasma membrane domain of polarized epithelial cells, where they can present Ag to intraepithelial lymphocytes in the vascular space. We have analyzed the sorting information required for efficient intracellular localization and polarized distribution of MHC class II molecules in stably transfected Madin-Darby canine kidney cells. These cells were able to present influenza virus particles to HLA-DR1-restricted T cell clones. Wild-type MHC class II molecules were located on the basolateral plasma membrane domain, in basolateral early endosomes, and in late multivesicular endosomes, the latter also containing the MHC class II-associated invariant chain and an HLA-DM fusion protein. A phenylalanine-leucine residue within the cytoplasmic tail of the beta-chain was required for basolateral distribution, efficient internalization, and localization of the MHC class II molecules to basolateral early endosomes. However, distribution to apically located, late multivesicular endosomes did not depend on signals in the class II cytoplasmic tails as both wild-type class II molecules and mutant molecules lacking the phenylalanine-leucine motif were found in these compartments. Our results demonstrate that sorting information in the tails of class II dimers is an absolute requirement for their basolateral surface distribution and intracellular localization.
authors.affiliation: Department of Biology, University of Oslo, Norway.
authors.forename: A
authors.initials: A
authors.lastname: Simonsen
authors.forename: K W
authors.initials: KW
authors.lastname: Pedersen
authors.forename: T W
authors.initials: TW
authors.lastname: Nordeng
authors.forename: A
authors.initials: A
authors.lastname: von der Lippe
authors.forename: E
authors.initials: E
authors.lastname: Stang
authors.forename: E O
authors.initials: EO
authors.lastname: Long
authors.forename: O
authors.initials: O
authors.lastname: Bakke
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017951:Antigen Presentation / Q000235:genetics; D000944:Antigens, Differentiation, B-Lymphocyte / Q000502:physiology*; D001692:Biological Transport / Q000276:immunology; D002451:Cell Compartmentation / Q000235:genetics / Q000276:immunology; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology / Q000378:metabolism; D016764:Cell Polarity / Q000276:immunology*; D003593:Cytoplasm / Q000276:immunology*; D004285:Dogs; D011992:Endosomes / Q000276:immunology / Q000378:metabolism; D006681:HLA-D Antigens / Q000235:genetics / Q000378:metabolism; D015798:HLA-DR1 Antigen / Q000378:metabolism*; D000949:Histocompatibility Antigens Class II / Q000502:physiology*; D006801:Humans; D007668:Kidney; D007930:Leucine / Q000502:physiology*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology*; D014162:Transfection
chemical_list: D000944:Antigens, Differentiation, B-Lymphocyte; C416189:H2-M antigens; D006681:HLA-D Antigens; C084245:HLA-DM antigens; D015798:HLA-DR1 Antigen; D000949:Histocompatibility Antigens Class II; D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; C045084:invariant chain; D007930:Leucine