Raft association of SNAP receptors acting in apical trafficking in Madin-Darby canine kidney cells

Proc Natl Acad Sci U S A. 1999 Mar 30;96(7):3734-8. doi: 10.1073/pnas.96.7.3734.

Abstract

We have investigated the relationships between the apical sorting mechanism using lipid rafts and the soluble N-ethyl maleimide-sensitive factor attachment protein receptor (SNARE) machinery, which is involved in membrane docking and fusion. We first confirmed that anti-alpha-SNAP antibodies inhibit the apical pathway in Madin- Darby canine kidney (MDCK) cells; in addition, we report that a recombinant SNAP protein stimulates the apical transport whereas a SNAP mutant inhibits this transport step. Based on t-SNARE overexpression experiments and the effect of botulinum neurotoxin E, syntaxin 3 and SNAP-23 have been implicated in apical membrane trafficking. Here, we show in permeabilized MDCK cells that antisyntaxin 3 and anti-SNAP-23 antibodies lower surface delivery of an apical reporter protein. Moreover, using a similar approach, we show that tetanus toxin-insensitive, vesicle-associated membrane protein (TI-VAMP; also called VAMP7), a recently described apical v-SNARE, is involved. Furthermore, we show the presence of syntaxin 3 and TI-VAMP in isolated apical carriers. Polarized apical sorting has been postulated to be mediated by the clustering of apical proteins into dynamic sphingolipid-cholesterol rafts. We provide evidence that syntaxin 3 and TI-VAMP are raft-associated. These data support a raft-based mechanism for the sorting of not only apically destined cargo but also of SNAREs having functions in apical membrane-docking and fusion events.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies / pharmacology
  • Carrier Proteins / metabolism
  • Cell Line
  • Dogs
  • Genes, Reporter
  • Kidney
  • Membrane Proteins / analysis
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Membrane Proteins / physiology*
  • Molecular Sequence Data
  • Peptide Fragments / immunology
  • Qa-SNARE Proteins
  • Qb-SNARE Proteins
  • Qc-SNARE Proteins
  • R-SNARE Proteins
  • Rabbits
  • Recombinant Proteins / analysis
  • Recombinant Proteins / metabolism
  • SNARE Proteins
  • Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins
  • Vesicular Transport Proteins*

Substances

  • Antibodies
  • Carrier Proteins
  • Membrane Proteins
  • Peptide Fragments
  • Qa-SNARE Proteins
  • Qb-SNARE Proteins
  • Qc-SNARE Proteins
  • R-SNARE Proteins
  • Recombinant Proteins
  • SNAP23 protein, human
  • SNARE Proteins
  • Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins
  • VAMP7 protein, human
  • Vesicular Transport Proteins