Opposite effects of alfa-actinin and of fructose 1,6-bisphosphate aldolase on the microfilament network. The role of orthophosphate revisited.
At pH 7.5, in the presence of 0.1 M KCl, 2 mM MgCl2 and 15 mM phosphate, the binding of 1 molecule of alfa-actinin for each strand of 1000 actin monomers doubles the apparent viscosity of an F-actin solution (12 microM as the monomer). Further binding of one molecule of aldolase for each strand of 280 actin monomers halves the apparent viscosity of the alfa-actinin-F-actin system without any desorption of alfa-actinin. The effect of aldolase is not hindered by the addition of 0.1 mM fructose 1,6-bisphosphate. It is shown that orthophosphate acts as a damper of the regulatory effect of fructose bisphosphate on the interaction between aldolase and microfilaments.
Grazi
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Istituto di Chimica Biologica, Università di Ferrara, Italy.
Guidoboni
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D008841:Actin Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D000185:Actinin / Q000378:metabolism* / Q000648:ultrastructure; D000199:Actins / Q000378:metabolism; D000818:Animals; D002645:Chickens; D003599:Cytoskeleton / Q000378:metabolism*; D005033:Ethylmaleimide / Q000378:metabolism; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism*; D008854:Microscopy, Electron; D010710:Phosphates / Q000378:metabolism*; D011817:Rabbits; D014783:Viscosity
D000199:Actins; D010710:Phosphates; D000185:Actinin; D005634:Fructose-Bisphosphate Aldolase; D005033:Ethylmaleimide