Decrease in cytoskeleton-bound phosphofructokinase in muscle induced by high intracellular calcium, serotonin and phospholipase A2 in vivo.
1. Particulate (cytoskeleton-bound) and soluble phosphofructokinase (PFK), separated from rat muscle, exhibited different allosteric properties; in contrast to the soluble PFK, the bound enzyme was not sensitive to allosteric regulation. 2. Treatment of muscle with Ca2(+)-ionophore A23187, serotonin, or phospholipase A2, reduced the binding of PFK and aldolase. 3. The decrease in enzymes' binding was most probably mediated by the rise in free intracellular Ca2+ induced by these agents, as we found that direct addition of Ca2+ to the particulate fraction of muscle, caused solubilization of bound PFK and aldolase. 4. The reduction in binding of PFK and aldolase to cytoskeletal proteins, may have a deleterious effect on muscle function and structure, and may be involved in the mechanism of muscle damage in pathological conditions where accumulation of Ca2+ occurs.
Lilling
G
G
Department of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel.
Beitner
R
R
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism / Q000494:pharmacology*; D003599:Cytoskeleton / Q000201:enzymology*; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism; D009132:Muscles / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D010732:Phosphofructokinase-1 / Q000378:metabolism*; D010741:Phospholipases A / Q000494:pharmacology*; D054467:Phospholipases A2; D051381:Rats; D012701:Serotonin / Q000494:pharmacology*
D012701:Serotonin; D000001:Calcimycin; D010732:Phosphofructokinase-1; D010741:Phospholipases A; D054467:Phospholipases A2; D005634:Fructose-Bisphosphate Aldolase; D002118:Calcium