title: Okadaic acid induces Golgi apparatus fragmentation and arrest of intracellular transport.
abstract: The specific phosphatase inhibitor okadaic acid (OA) induced fragmentation of the Golgi apparatus in interphase HeLa cells. Immunoelectron microscopy for galactosyltransferase identified a major Golgi fragment composed of a cluster of vesicles and tubules that was morphologically indistinguishable from the 'Golgi cluster' previously described in mitotic cells. The presence of homogeneous immunofluorescence staining for galactosyltransferase in OA-treated cells also suggested that isolated Golgi vesicles, previously found in mitotic cells, existed along with the clusters. After removal of OA, both clusters and vesicles appeared to participate in a reassembly pathway that strongly resembled that occurring during telophase. OA also induced inhibition of intracellular transport, another feature of mitotic cells. OA treatment prevented newly synthesised G protein of vesicular stomatitis virus (VSV) from acquiring resistance to endoglycosidase H and from arriving at the cell surface. In addition, fluid phase endocytosis of horseradish peroxidase (HRP) was reduced to less than 10% of control values. All these effects were dose-dependent and reversible. OA should be a useful tool to study the Golgi division and membrane traffic.
authors.affiliation: Department of Anatomy, University of Berne, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Lucocq
authors.forename: G
authors.initials: G
authors.lastname: Warren
authors.forename: J
authors.initials: J
authors.lastname: Pryde
mesh_terms: D001692:Biological Transport / Q000502:physiology; D004705:Endocytosis / Q000502:physiology*; D004988:Ethers, Cyclic / Q000494:pharmacology*; D005700:Galactosyltransferases / Q000378:metabolism; D006056:Golgi Apparatus / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D006367:HeLa Cells; D006735:Horseradish Peroxidase / Q000378:metabolism; D006801:Humans; D007399:Interphase / Q000502:physiology*; D007476:Ionophores / Q000494:pharmacology; D008562:Membrane Glycoproteins; D008856:Microscopy, Fluorescence / Q000379:methods; D009024:Morphogenesis; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors; D014759:Viral Envelope Proteins / Q000378:metabolism
chemical_list: D004988:Ethers, Cyclic; C028391:G protein, vesicular stomatitis virus; D007476:Ionophores; D008562:Membrane Glycoproteins; D014759:Viral Envelope Proteins; D019319:Okadaic Acid; D006735:Horseradish Peroxidase; D005700:Galactosyltransferases; D010749:Phosphoprotein Phosphatases