Syntaxin 16 binds to cystic fibrosis transmembrane conductance regulator and regulates its membrane trafficking in epithelial cells

J Biol Chem. 2010 Nov 12;285(46):35519-27. doi: 10.1074/jbc.M110.162438. Epub 2010 Sep 8.

Abstract

The cystic fibrosis transmembrane conductance regulator (CFTR) is a key membrane protein in the complex network of epithelial ion transporters regulating epithelial permeability. Syntaxins are one of the major determinants in the intracellular trafficking and membrane targeting of secretory proteins. In the present study we demonstrate the biochemical and functional association between CFTR and syntaxin 16 (STX16) that mediates vesicle transport within the early/late endosomes and trans-Golgi network. Immunoprecipitation experiments in rat colon and T84 human colonic epithelial cells indicate that STX16 associates with CFTR. Further analyses using the domain-specific pulldown assay reveal that the helix domain of STX16 directly interacts with the N-terminal region of CFTR. Immunostainings in rat colon and T84 cells show that CFTR and STX16 highly co-localize at the apical and subapical regions of epithelial cells. Interestingly, CFTR-associated chloride current was reduced by the knockdown of STX16 expression in T84 cells. Surface biotinylation and recycling assays indicate that the reduction in CFTR chloride current is due to decreased CFTR expression on the plasma membrane. These results suggest that STX16 mediates recycling of CFTR and constitutes an important component of CFTR trafficking machinery in intestinal epithelial cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Cell Line, Tumor
  • Cell Membrane / metabolism*
  • Cystic Fibrosis Transmembrane Conductance Regulator / genetics
  • Cystic Fibrosis Transmembrane Conductance Regulator / metabolism*
  • Endosomes / metabolism
  • Epithelial Cells / metabolism*
  • HEK293 Cells
  • Humans
  • Immunoblotting
  • Immunoprecipitation
  • Protein Binding
  • Protein Transport
  • RNA Interference
  • Rats
  • Rats, Sprague-Dawley
  • Syntaxin 16 / genetics
  • Syntaxin 16 / metabolism*
  • trans-Golgi Network / metabolism

Substances

  • Syntaxin 16
  • Cystic Fibrosis Transmembrane Conductance Regulator