Coatomer, but not P200/myosin II, is required for the in vitro formation of trans-Golgi network-derived vesicles containing the envelope glycoprotein of vesicular stomatitis virus

Proc Natl Acad Sci U S A. 1998 Feb 3;95(3):1073-8. doi: 10.1073/pnas.95.3.1073.

Abstract

Using a cytosol and nucleotide dependent assay that we previously developed, we have investigated the requirement for coat proteins in the in vitro production of trans-Golgi network (TGN)-derived vesicles from a Madin-Darby canine kidney (MDCK) cell Golgi fraction that contains the 35S-labeled, terminally glycosylated, envelope glycoprotein of vesicular stomatitis virus (VSV-G) accumulated in the TGN. We found that the TGN-derived vesicles, like those involved in intra-Golgi transport and in retrograde transport to the endoplasmic reticulum, contain a coatomer coat and that coatomer is required for their formation. Thus, after they are produced with GTPgammaS, the coated vesicles could be captured on beads containing anticoatomer antibody. Moreover, a cytosolic protein fraction depleted of coatomer could not support vesicle formation but it did so after purified coatomer was added. We also determined that P200/myosin II does not play an essential role in the in vitro generation of TGN-derived vesicles. Thus, removal of this protein from the cytosol, by differential salt precipitation or binding to phalloidin-induced actin filaments, had no effect on vesicle generation. Nevertheless, immunodepletion of cytosol using the anti-P200/myosin II AD7 antibody abolished vesicle generation and that antibody was capable of effectively immunocapturing coated vesicles, even when these were generated in the absence of P200/myosin II. These effects, however, are explained by the unexpected finding that the AD7 antibody interacts with undenatured coatomer.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antibodies / metabolism
  • Cell Line
  • Coated Vesicles / metabolism*
  • Coated Vesicles / ultrastructure
  • Coatomer Protein
  • Cytosol / metabolism
  • Dogs
  • Golgi Apparatus / metabolism*
  • Golgi Apparatus / ultrastructure
  • Liver / metabolism
  • Membrane Glycoproteins*
  • Membrane Proteins / metabolism*
  • Microscopy, Electron
  • Myosins / immunology
  • Myosins / metabolism*
  • Rats
  • Viral Envelope Proteins / metabolism*

Substances

  • Antibodies
  • Coatomer Protein
  • G protein, vesicular stomatitis virus
  • Membrane Glycoproteins
  • Membrane Proteins
  • Viral Envelope Proteins
  • Myosins