title: Degradation of connexins from the plasma membrane is regulated by inhibitors of protein synthesis.
abstract: Little is known about the mechanism and regulation of connexin turnover from the plasma membrane. We have used a combination of cell surface biotinylation, immunofluorescence microscopy, and scrape-load dye transfer assays to investigate the effect of the protein synthesis inhibitor cycloheximide on connexin43 and connexin32 after their transport to the plasmalemma. The results obtained demonstrate that cycloheximide inhibits the turnover of connexins from the surface of both gap junction assembly-deficient and -efficient cells. Moreover, cell surface connexin saved from destruction by cycloheximide can assemble into long-lived, functional gap junctional plaques. These findings support the concept that downregulation of connexin degradation from the plasma membrane can serve as a mechanism to enhance gap junction-mediated intercellular communication.
authors.affiliation: Division of Molecular Medicine, Oregon Health Science University, Portland, OR 97239, USA.
authors.forename: Judy K
authors.initials: JK
authors.lastname: VanSlyke
authors.forename: Linda S
authors.initials: LS
authors.lastname: Musil
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D016466:CHO Cells; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D018031:Connexin 43 / Q000378:metabolism*; D017630:Connexins / Q000378:metabolism*; D006224:Cricetinae; D003412:Cricetulus; D003513:Cycloheximide / Q000494:pharmacology*; D017629:Gap Junctions / Q000378:metabolism; D008856:Microscopy, Fluorescence; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D000097002:Gap Junction beta-1 Protein
chemical_list: D018031:Connexin 43; D017630:Connexins; D003513:Cycloheximide; D011500:Protein Synthesis Inhibitors; D000097002:Gap Junction beta-1 Protein