PDZ domain interaction controls the endocytic recycling of the cystic fibrosis transmembrane conductance regulator

Agnieszka Swiatecka-Urban, Marc Duhaime, Bonita Coutermarsh, Katherine H. Karlson, James Collawn, Michal Milewski, Garry R. Cutting, William B. Guggino, George Langford, Bruce A. Stanton

Research output: Contribution to journalArticle

161 Scopus citations

Abstract

The C terminus of CFTR contains a PDZ interacting domain that is required for the polarized expression of cystic fibrosis transmembrane conductance regulator (CFTR) in the apical plasma membrane of polarized epithelial cells. To elucidate the mechanism whereby the PDZ interacting domain mediates the polarized expression of CFTR, Madin-Darby canine kidney cells were stably transfected with wild type (wt-CFTR) or C-terminally truncated human CFTR (CFTR-ΔTRL). We tested the hypothesis that the PDZ interacting domain regulates sorting of CFTR from the Golgi to the apical plasma membrane. Pulse-chase studies in combination with domain-selective cell surface biotinylation revealed that newly synthesized wt-CFTR and CFTR-ΔTRL were targeted equally to the apical and basolateral membranes in a nonpolarized fashion. Thus, the PDZ interacting domain is not an apical sorting motif. Deletion of the PDZ interacting domain reduced the half-life of CFTR in the apical membrane from ∼24 to ∼13 h but had no effect on the half-life of CFTR in the basolateral membrane. Thus, the PDZ interacting domain is an apical membrane retention motif. Next, we examined the hypothesis that the PDZ interacting domain affects the apical membrane half-life of CFTR by altering its endocytosis and/or endocytic recycling. Endocytosis of wt-CFTR and CFTR-ΔTRL did not differ. However, endocytic recycling of CFTR-ΔTRL was decreased when compared with wt-CFTR. Thus, deletion of the PDZ interacting domain reduced the half-life of CFTR in the apical membrane by decreasing CFTR endocytic recycling. Our results identify a new role for PDZ proteins in regulating the endocytic recycling of CFTR in polarized epithelial cells.

Original languageEnglish (US)
Pages (from-to)40099-40105
Number of pages7
JournalJournal of Biological Chemistry
Volume277
Issue number42
DOIs
StatePublished - Oct 18 2002

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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