Article abstract
Nature Cell Biology 5, 126 - 136 (2003)
Published online: 27 January 2003 | doi:10.1038/ncb917
Three-dimensional analysis of post-Golgi carrier exocytosis in epithelial cells
Geri Kreitzer1, Jan Schmoranzer3,4, Seng Hui Low5, Xin Li5, Yunbo Gan1, Thomas Weimbs5, Sanford M Simon3 & Enrique Rodriguez-Boulan1,2
Abstract
Targeted delivery of proteins to distinct plasma membrane domains is critical to the development and maintenance of polarity in epithelial cells. We used confocal and time-lapse total internal reflection fluorescence microscopy (TIR-FM) to study changes in localization and exocytic sites of post-Golgi transport intermediates (PGTIs) carrying GFP-tagged apical or basolateral membrane proteins during epithelial polarization. In non-polarized Madin Darby Canine Kidney (MDCK) cells, apical and basolateral PGTIs were present throughout the cytoplasm and were observed to fuse with the basal domain of the plasma membrane. During polarization, apical and basolateral PGTIs were restricted to different regions of the cytoplasm and their fusion with the basal membrane was completely abrogated. Quantitative analysis suggested that basolateral, but not apical, PGTIs fused with the lateral membrane in polarized cells, correlating with the restricted localization of Syntaxins 4 and 3 to lateral and apical membrane domains, respectively. Microtubule disruption induced Syntaxin 3 depolarization and fusion of apical PGTIs with the basal membrane, but affected neither the lateral localization of Syntaxin 4 or Sec6, nor promoted fusion of basolateral PGTIs with the basal membrane.
- Margaret M. Dyson Vision Research Institute, Weill Medical College of Cornell University, New York, NY 10021, USA
- Department of Cell Biology, Weill Medical College of Cornell University, New York, NY 10021, USA
- Laboratory of Cellular Biophysics, Rockefeller University, New York, NY 10021, USA
- Department of Biology, Chemistry, Pharmacology, Free University, Berlin 14195, Germany
- Department of Cell Biology, Lerner Research Institute and the Glickman Urological Institute, The Cleveland Clinic, Cleveland, OH 44195, USA
Correspondence to: Geri Kreitzer1 e-mail: ggurlan@med.cornell.edu
Correspondence to: Enrique Rodriguez-Boulan1,2 e-mail: boulan@med.cornell.edu
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