Different requirements for NSF, SNAP, and Rab proteins in apical and basolateral transport in MDCK cells.
We used an in vitro system based on streptolysin O-permeabilized MDCK cells to study the involvement of NSF, SNAP, SNAREs, and Rab proteins in polarized membrane transport of epithelial cells. In MDCK cells, transport from the trans-Golgi network (TGN) to the basolateral plasma membrane is inhibited by anti-NSF antibodies and stimulated by alpha-SNAP. In contrast, transport from the TGN to the apical cell surface is not affected by anti-NSF antibodies or alpha-SNAP. Furthermore, apical transport is insensitive to Rab-GDI and tetanus and botulinum neurotoxins, which inhibit basolateral transport. These results provide evidence that the Rab-NSF-SNAP-SNARE mechanism operates in basolateral transport, while other molecules constitute the machinery for vesicular delivery in the apical pathway.
Ikonen
E
E
Cell Biology Programme, European Molecular Biology Laboratory, Heidelberg, Federal Republic of Germany.
Tagaya
M
M
Ullrich
O
O
Montecucco
C
C
Simons
K
K
D000818:Animals; D001692:Biological Transport; D002352:Carrier Proteins / Q000378:metabolism*; D016764:Cell Polarity; D002478:Cells, Cultured; D004285:Dogs; D004848:Epithelium / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D052066:N-Ethylmaleimide-Sensitive Proteins; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D033921:Vesicular Transport Proteins
D002352:Carrier Proteins; D008565:Membrane Proteins; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D033921:Vesicular Transport Proteins; D019204:GTP-Binding Proteins; D052066:N-Ethylmaleimide-Sensitive Proteins