title: Endothelial nitric oxide synthase and its negative regulator caveolin-1 localize to distinct perinuclear organelles.
abstract: Caveolin-1 is a member of a subset of intracellular proteins that regulate endothelial nitric oxide synthase (eNOS) activity. In caveolae, caveolin-1 inhibits eNOS activity via a direct interaction with the enzyme. Previous work has indicated that both eNOS and caveolin-1 are also localized at the perinuclear Golgi complex. Whether caveolin-1 is involved in eNOS regulation in this cell compartment is unknown. Here we studied the localization of eNOS and caveolin-1 in the perinuclear region of primary bovine aortic endothelial cells. By immunofluorescence microscopy we show that both eNOS and caveolin-1 co-localize with Golgi markers. On treatment of the cells with the microtubule-depolymerizing drug nocodazole, the Golgi complex is scattered and caveolin-1 is found in vesicles at the periphery of the cell, while eNOS is localized at large structures near the nucleus. The nocodazole-induced redistribution of eNOS is similar to that of cis-, medial-, and trans-Golgi markers, while the caveolin-1 redistribution resembles that of sec22, a marker for the intermediate compartment. The localization of eNOS and caveolin-1 at distinct perinuclear compartments that behave differently in the presence of nocodazole indicates that eNOS activity is not regulated by caveolin-1 in the Golgi complex.
authors.affiliation: Department of Vascular Medicine, UMC Utrecht, Utrecht, The Netherlands. r.govers@garvan.org.au
authors.forename: Roland
authors.initials: R
authors.lastname: Govers
authors.forename: Peter
authors.initials: P
authors.lastname: van der Sluijs
authors.forename: Elly
authors.initials: E
authors.lastname: van Donselaar
authors.forename: Jan-Willem
authors.initials: JW
authors.lastname: Slot
authors.forename: Ton J
authors.initials: TJ
authors.lastname: Rabelink
mesh_terms: D000818:Animals; D001011:Aorta / Q000166:cytology; D002417:Cattle; D051242:Caveolin 1; D022461:Caveolins / Q000378:metabolism*; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000201:enzymology / Q000378:metabolism* / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000201:enzymology / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III; D015739:Nocodazole / Q000494:pharmacology
chemical_list: D051242:Caveolin 1; D022461:Caveolins; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D015739:Nocodazole