Potent inhibition of dynein adenosinetriphosphatase and of the motility of cilia and sperm flagella by vanadate.

AUTOR(ES)

Gibbons, I R

RESUMO

The motility of demembranated sea urchin sperm flagella and that of embryo cilia reactivated with 0.1 mM ATP are completely inhibited by 4 micron and 0.5 micron vanadium(V) [V(V), in vanadate], respectively. The Mg2+-activated ATPase activity (ATP phosphohydrolase, EC 3.6.1.3)of the latent form of dynein 1 is inhibited 50% by 0.5-1 micron V(V), while the Ca2+-activated ATPase activity is much less sensitive. The inhibition of flagellar beat frequency and of dynein 1 ATPase activity by V(V) appears not to be competitive with ATP. In agreement with other reports, the inhibition of (Na,K)-ATPase by V(V) shows a slow onset in the presence of ATP and is relatively rapid in its absence. With dynein, however, the inhibition occurs at a rapid rate whether or not ATP is present. Catechol at a concentration of 1 mM reverses the V(V) inhibition of reactivated sperm motility, dynein ATPase, and (Na, K)-ATPase. Myosin and actomyosin ATPases show no inhibition by concentrations of V(V) up to 500 micron. The inhibition by V(V) provides a possible technique for distinguishing between the actions of dynein and myosin in different forms of cell motility.

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