Endothelial nitric oxide synthase and its negative regulator caveolin-1 localize to distinct perinuclear organelles.
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.
Govers
Roland
R
Department of Vascular Medicine, UMC Utrecht, Utrecht, The Netherlands. r.govers@garvan.org.au
van der Sluijs
Peter
P
van Donselaar
Elly
E
Slot
Jan-Willem
JW
Rabelink
Ton J
TJ
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
D051242:Caveolin 1; D022461:Caveolins; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D015739:Nocodazole