S-NO-actin: S-nitrosylation kinetics and the effect on isolated vascular smooth muscle.
We describe the modification of reactive actin sulfhydryls by S-nitrosoglutathione. Kinetics of S-nitrosylation and denitrosylation suggest that only one cysteine of actin is involved in the reactions. By using the bifunctional sulfhydryl cross-linking reagent N,N'-1,4-phenylenebismaleimide and the monofunctional reagent N-iodoacetyl-N'-(5-sulpho-1-naphthyl)ethylenediamine, we identified this residue as Cys374. The time course of filament formation followed by high-shear viscosity changes revealed that S-nitrosylated G-actin polymerizes less efficiently than native monomers. The observed decrease in specific viscosity at steady state is due mainly to a marked inhibition of filament end-to-end annealing and, partially, to a reduction in F-actin concentration. Finally, S-nitrosylated actin acts as nitric oxide donor showing a fast, potent vasodilating activity at unusually low concentrations, being comparable with that of low molecular weight nitrosothiols.
Dalle-Donne
I
I
Lab. Biochem. Biophys. Cytoskel., Department of Biology, University of Milan, Italy.
Milzani
A
A
Giustarini
D
D
Di Simplicio
P
P
Colombo
R
R
Rossi
R
R
D000199:Actins / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D003432:Cross-Linking Reagents / Q000494:pharmacology; D005978:Glutathione / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000378:metabolism* / Q000494:pharmacology; D009574:Nitro Compounds / Q000378:metabolism* / Q000494:pharmacology; D011817:Rabbits
D000199:Actins; D003432:Cross-Linking Reagents; D020030:Nitric Oxide Donors; D009574:Nitro Compounds; C116027:S-nitroglutathione; D005978:Glutathione