Effect of fluoride on movement of concanavalin A-acceptor molecules of human neutrophils.
The effects of fluoride (F) on neutrophil protuberance formation and induced Con A acceptor molecule migration were assessed microscopically. Below 5 mM, F had little effect on acceptor migration, while it markedly inhibited formation of colchicine-induced protuberances. The anion also increased the rate at which preformed protuberances regressed. Since protuberance formation is enhanced by disassembly of microtubules, these data suggest that F promotes and/or stabilizes microtubule assembly. Microtubule assembly is favored by binding of GTP to tubulin subunits, while GDP binding favors disassembly of microtubules. Since F binds with GDP, forming a new complex that mimics GTP, the anion would be expected to enhance microtubule assembly. Over the same F concentration range, the anion failed to inhibit acceptor polarization, but did inhibit cytochalasin B-enhanced dispersion of prepolarized Con A acceptors, implying that, at low concentrations, F also affected microfilament cycling. Concentrations of F in excess of 5 mM inhibited acceptor migration as well as protuberance formation. At 20 mM, the anion abolished both events, yet at this same concentration F induced neutrophil superoxide generation and degranulation, suggesting that acceptor migration is not a prerequisite for these two neutrophil effector activities.
Gabler
W L
WL
Department of Biochemistry, Oregon Health Sciences University, School of Dentistry, Portland 97201.
Mugrditchian
M
M
Creamer
H R
HR
Bullock
W W
WW
D008841:Actin Cytoskeleton / Q000187:drug effects; D002465:Cell Movement; D003078:Colchicine / Q000494:pharmacology; D003080:Cold Temperature; D003571:Cytochalasin B / Q000494:pharmacology; D005459:Fluorides / Q000494:pharmacology*; D006801:Humans; D007152:Immunologic Capping / Q000187:drug effects*; D008856:Microscopy, Fluorescence; D008870:Microtubules / Q000187:drug effects; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D011940:Receptor Aggregation / Q000187:drug effects*; D011952:Receptors, Concanavalin A / Q000187:drug effects*
D011952:Receptors, Concanavalin A; D003571:Cytochalasin B; D005459:Fluorides; D003078:Colchicine