title: Ilimaquinone inhibits gap-junctional communication prior to Golgi fragmentation and block in protein transport.
abstract: Brefeldin A and ilimaquinone are compounds known to affect Golgi structure and function. In particular, the transport of proteins is blocked either at the level of exit from endoplasmic reticulum (brefeldin) or at cis-Golgi (ilimaquinone). Brefeldin caused a slow decrease in gap-junctional communication and a slow loss of all phosphorylated forms of connexin43 in hamster and rat fibroblasts, while ilimaquinone caused an abrupt decrease in gap-junctional communication and rapid loss of only the slowest migrating phosphorylated connexin43 band (P2). Ilimaquinone caused these effects prior to any significant Golgi fragmentation, especially in hamster fibroblasts. Concurrently, ilimaquinone minimally affected protein secretion, while brefeldin caused an instantaneous decrease. These results show that ilimaquinone inhibits gap-junctional communication in connexin43-expressing cells by a mechanism not dependent on Golgi fragmentation or block in protein transport.
authors.affiliation: Department of Environmental and Occupational Cancer, Institute for Cancer Research, The Norwegian Radium Hospital, N-0310, Oslo, Norway.
authors.forename: Véronique
authors.initials: V
authors.lastname: Cruciani
authors.forename: Edward
authors.initials: E
authors.lastname: Leithe
authors.forename: Svein Ole
authors.initials: SO
authors.lastname: Mikalsen
mesh_terms: D000818:Animals; D001324:Autoantigens; D020126:Brefeldin A / Q000494:pharmacology; D002450:Cell Communication / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D020756:Coatomer Protein / Q000187:drug effects / Q000378:metabolism; D018031:Connexin 43 / Q000187:drug effects / Q000378:metabolism; D006224:Cricetinae; D005057:Eukaryotic Cells / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D017629:Gap Junctions / Q000187:drug effects* / Q000378:metabolism; D006056:Golgi Apparatus / Q000187:drug effects* / Q000473:pathology / Q000648:ultrastructure; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000187:drug effects / Q000378:metabolism; D008854:Microscopy, Electron; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D021381:Protein Transport / Q000187:drug effects* / Q000502:physiology; D011809:Quinones / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D012717:Sesquiterpenes / Q000494:pharmacology*
chemical_list: D001324:Autoantigens; D020756:Coatomer Protein; D018031:Connexin 43; C097741:Golgin subfamily A member 2; D008565:Membrane Proteins; D011500:Protein Synthesis Inhibitors; D011809:Quinones; D012717:Sesquiterpenes; D020126:Brefeldin A; C467077:ilimaquinone