ADP-ribosylation factor 6 and endocytosis at the apical surface of Madin-Darby canine kidney cells

J Cell Biol. 1999 Oct 4;147(1):7-12. doi: 10.1083/jcb.147.1.7.


We report that the small GTPase, ADP-ribosylation factor 6 (ARF6), is present only on the apical surface of polarized MDCK epithelial cells. Overexpression of a mutant of ARF6, ARF6-Q67L, which is predicted to be in the GTP-bound form, stimulates endocytosis exclusively at this surface. Surprisingly, overexpression of the mutant ARF6-T27N, which is predicted to be in the GDP-bound form, also stimulated apical endocytosis, though to a lesser extent. ARF6-stimulated endocytosis is inhibited by a dominant-negative form of dynamin, or a dominant-negative hub fragment of clathrin heavy chain, indicating that it is mediated by clathrin. Correspondingly, overexpression of either mutant of ARF6 leads to an increase in the number of clathrin-coated pits at the apical plasma membrane. When ARF6-Q67L is overexpressed in the presence of the dominant-negative dynamin, the ARF6-Q67L colocalizes with clathrin and with IgA bound to its receptor. We conclude that ARF6 is an important modulator of clathrin-mediated endocytosis at the apical surface of epithelial cells.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • ADP-Ribosylation Factor 6
  • ADP-Ribosylation Factors / genetics
  • ADP-Ribosylation Factors / metabolism*
  • Animals
  • Cell Line
  • Cell Polarity*
  • Clathrin / genetics
  • Clathrin / metabolism*
  • Clathrin Heavy Chains
  • Coated Pits, Cell-Membrane / metabolism
  • Coated Pits, Cell-Membrane / ultrastructure
  • Dogs
  • Dynamins
  • Endocytosis*
  • Epithelial Cells / cytology*
  • Epithelial Cells / metabolism
  • Epithelial Cells / ultrastructure
  • GTP Phosphohydrolases / genetics
  • GTP Phosphohydrolases / metabolism
  • Genes, Dominant / genetics
  • Guanosine Diphosphate / metabolism
  • Guanosine Triphosphate / metabolism
  • Immunoglobulin A / immunology
  • Kidney
  • Microscopy, Electron
  • Mutation
  • Peptide Fragments / genetics
  • Peptide Fragments / metabolism
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism


  • ADP-Ribosylation Factor 6
  • Clathrin
  • Immunoglobulin A
  • Peptide Fragments
  • Recombinant Proteins
  • Clathrin Heavy Chains
  • Guanosine Diphosphate
  • Guanosine Triphosphate
  • GTP Phosphohydrolases
  • ADP-Ribosylation Factors
  • Dynamins