Evidence for novel 30,000-50,000Mr cofactor in the activation of muscle.
A new approach is described for reconstituting a fully desensitized skeletal muscle fiber to restore its contractility. These studies revealed a novel regulatory cofactor, 30-50,000Mr by filtration (26-55kDa by SDS PAGE). It was shown to be critical for the Ca2+-activation in the physiological milieu. The cofactor was present in skeletal and cardiac muscles as well as in brain, but not in kidney and liver. The cofactor may be a second Ca2+ switch in a dual-regulation scheme for vertebrate muscle, or could provide an essential link in the cross-bridge cycle beyond activation.
Gulati
J
J
Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461.
Babu
A
A
D000818:Animals; D001923:Brain Chemistry; D002118:Calcium / Q000494:pharmacology; D006224:Cricetinae; D004591:Electrophoresis, Polyacrylamide Gel; D007668:Kidney / Q000032:analysis; D008099:Liver / Q000032:analysis; D008970:Molecular Weight; D009119:Muscle Contraction; D009124:Muscle Proteins / Q000032:analysis / Q000502:physiology*; D009132:Muscles / Q000032:analysis / Q000502:physiology*; D009206:Myocardium / Q000032:analysis; D014462:Ultrafiltration
D009124:Muscle Proteins; D002118:Calcium