Does Regulatory Protein Play a Role in Glucokinase Localization?

The enzyme glucokinase has recently been found to be largely responsible for glucose homeostatic responses of both the liver and pancreas. The 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-sensitive manner, and we present evidence for the interaction of these proteins with F-actin. Glucokinase regulatory protein gelled F-actin, and gelation was specifically inhibited by glucokinase and the regulatory protein effectors fructose-1-phosphate (F1P) and fructose-6-phosphate (F6P). These results suggest that glucokinase regulatory protein may play a role in metabolism-sensitive glucokinase localization in vivo.