SNARE protein trafficking in polarized MDCK cells.
A key feature of polarized epithelial cells is the ability to maintain the specific biochemical composition of the apical and basolateral plasma membrane domains. This polarity is generated and maintained by the continuous sorting of apical and basolateral components in the secretory and endocytic pathways. Soluble N-ethyl maleimide-sensitive factor attachment protein receptors (SNARE) proteins of vesicle-associated membrane protein (VAMP) and syntaxin families have been suggested to play a role in the biosynthetic transport to the apical and basolateral plasma membranes of polarized cells, where they likely mediate membrane fusion. To investigate the involvement of SNARE proteins in membrane trafficking to the apical and basolateral plasma membrane in the endocytic pathway we have monitored the recycling of various VAMP and syntaxin molecules between intracellular compartments and the two plasma membrane domains in Madin-Darby canine kidney (MDCK) cells. Here we show that VAMP8/endobrevin cycles through the apical but not through the basolateral plasma membrane. Furthermore, we found that VAMP8 localizes to apical endosomal membranes in nephric tubule epithelium and in MDCK cells. This asymmetry in localization and cycling behavior suggests that VAMP8/endobrevin may play a role in apical endosomal trafficking in polarized epithelium cells.
Steegmaier
M
M
Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Stanford University School of Medicine, Stanford, CA 94305-5345, USA.
Lee
K C
KC
Prekeris
R
R
Scheller
R H
RH
D000818:Animals; D002460:Cell Line; D016764:Cell Polarity; D004285:Dogs; D004705:Endocytosis; D004847:Epithelial Cells / Q000378:metabolism; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins; D007425:Intracellular Membranes / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000378:metabolism*; D008164:Luminescent Proteins / Q000032:analysis / Q000235:genetics; D008565:Membrane Proteins / Q000378:metabolism*; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D021381:Protein Transport; D050765:Qa-SNARE Proteins; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D050600:SNARE Proteins; D014162:Transfection; D033921:Vesicular Transport Proteins
D008164:Luminescent Proteins; D008565:Membrane Proteins; D050765:Qa-SNARE Proteins; D011993:Recombinant Fusion Proteins; D050600:SNARE Proteins; D033921:Vesicular Transport Proteins; D049452:Green Fluorescent Proteins