The DnaJ-domain protein RME-8 functions in endosomal trafficking

J Biol Chem. 2005 Dec 2;280(48):40135-43. doi: 10.1074/jbc.M505036200. Epub 2005 Sep 22.

Abstract

Through a proteomic analysis of clathrin-coated vesicles from rat liver we identified the mammalian homolog of receptor-mediated endocytosis 8 (RME-8), a DnaJ domain-containing protein originally identified in a screen for endocytic defects in Caenorhabditis elegans. Mammalian RME-8 has a broad tissue distribution, and affinity selection assays reveal the ubiquitous chaperone Hsc70, which regulates protein conformation at diverse membrane sites as the major binding partner for its DnaJ domain. RME-8 is tightly associated with microsomal membranes and co-localizes with markers of the endosomal system. Small interfering RNA-mediated knock down of RME-8 has no influence on transferrin endocytosis but causes a reduction in epidermal growth factor internalization. Interestingly, and consistent with a localization to endosomes, knock down of RME-8 also leads to alterations in the trafficking of the cation-independent mannose 6-phosphate receptor and improper sorting of the lysosomal hydrolase cathepsin D. Our data demonstrate that RME-8 functions in intracellular trafficking and provides the first evidence of a functional role for a DnaJ domain-bearing co-chaperone on endosomes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Biological Transport
  • COS Cells
  • Caenorhabditis elegans
  • Caenorhabditis elegans Proteins / metabolism
  • Caenorhabditis elegans Proteins / physiology*
  • Cathepsin D / chemistry
  • Cations
  • Cell Membrane / metabolism
  • Cell Separation
  • Chlorocebus aethiops
  • Cholera Toxin / chemistry
  • Clathrin / chemistry
  • DNA, Complementary / metabolism
  • Endocytosis
  • Endosomes / metabolism*
  • Epidermal Growth Factor / metabolism
  • Flow Cytometry
  • Fluorescent Antibody Technique, Indirect
  • Fluorescent Dyes / pharmacology
  • Glutathione Transferase / metabolism
  • HSC70 Heat-Shock Proteins / metabolism
  • HSP40 Heat-Shock Proteins / chemistry*
  • Humans
  • Liver / metabolism
  • Lysosomes / metabolism
  • Microscopy, Fluorescence
  • Microsomes, Liver / metabolism
  • Molecular Chaperones / genetics
  • Molecular Chaperones / metabolism
  • Molecular Chaperones / physiology*
  • Molecular Sequence Data
  • Protein Binding
  • Protein Conformation
  • Protein Structure, Tertiary
  • Proteomics
  • RNA, Small Interfering / metabolism
  • Rats
  • Receptor, IGF Type 2 / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Subcellular Fractions / metabolism
  • Tissue Distribution
  • Transferrin / chemistry
  • Transferrin / metabolism

Substances

  • Caenorhabditis elegans Proteins
  • Cations
  • Clathrin
  • DNA, Complementary
  • DNAJC13 protein, human
  • DNAJC13 protein, rat
  • Fluorescent Dyes
  • HSC70 Heat-Shock Proteins
  • HSP40 Heat-Shock Proteins
  • Molecular Chaperones
  • RME-8 protein, C elegans
  • RNA, Small Interfering
  • Receptor, IGF Type 2
  • Recombinant Fusion Proteins
  • Transferrin
  • Epidermal Growth Factor
  • Cholera Toxin
  • Glutathione Transferase
  • Cathepsin D

Associated data

  • GENBANK/AY779857