title: Clathrin and Cx43 gap junction plaque endoexocytosis.
abstract: In earlier transmission electron microscopic studies, we have described pentilaminar gap junctional membrane invaginations and annular gap junction vesicles coated with short, electron-dense bristles. The similarity between these electron-dense bristles and the material surrounding clathrin-coated pits led us to suggest that the dense bristles associated with gap junction structures might be clathrin. To confirm that clathrin is indeed associated with annular gap junction vesicles and gap junction plaques, quantum dot immuno-electron microscopic techniques were used. We report here that clathrin associates with both connexin 43 (Cx43) gap junction plaques and pentilaminar gap junction vesicles. An important finding was the preferential localization of clathrin to the cytoplasmic surface of the annular or of the gap junction plaque membrane of one of the two contacting cells. This is consistent with the possibility that the direction of gap junction plaque internalization into one of two contacting cells is regulated by clathrin.
authors.affiliation: Department of Cell Biology and Physiology, University of Pittsburgh, School of Medicine, 324 South Biomedical Science Tower, Pittsburgh, PA 15261, USA.
authors.forename: Beth M
authors.initials: BM
authors.lastname: Nickel
authors.forename: B Hewa
authors.initials: BH
authors.lastname: DeFranco
authors.forename: Vernon L
authors.initials: VL
authors.lastname: Gay
authors.forename: Sandra A
authors.initials: SA
authors.lastname: Murray
mesh_terms: D045744:Cell Line, Tumor; D002966:Clathrin / Q000378:metabolism*; D018031:Connexin 43 / Q000378:metabolism*; D005089:Exocytosis; D017629:Gap Junctions / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D046529:Microscopy, Electron, Transmission / Q000379:methods; D016253:Microscopy, Immunoelectron / Q000379:methods; D045663:Quantum Dots
chemical_list: D002966:Clathrin; D018031:Connexin 43