DOES REGULATORY PROTEIN PLAY A ROLE IN GLUCOKINASE LOCALIZATION

The enzyme glucokinase has recently been found to be largely responsib le for glucose homeostatic responses of both the liver and pancreas. T he mechanism(s) of these responses remains unknown but recent studies suggest that the intracellular localization of glucokinase, controlled by glucokinase regulatory protein, may be important. This protein is known to bind to and inhibit glucokinase in a phosphofructose-sensitiv e manner, and we present evidence for the interaction of these protein s with F-actin. Glucokinase regulatory protein gelled F-actin, and gel ation was specifically inhibited by glucokinase and the regulatory pro tein effecters fructose-1-phosphate (F1P) and fructosed-phosphate (F6P ). These results suggest that glucokinase regulatory protein may play a role in metabolism-sensitive glucokinase localization in vivo.