The role of Ca2+ and calmodulin in insulin signalling in mammalian skeletal muscle.
The role of Ca2+ in mediating effects of insulin on skeletal muscle has been widely debated. It is believed that in skeletal muscle Ca2+ has a permissive role, necessary but not of prime importance in mediating the stimulatory actions of insulin. In this review, we present evidence that insulin causes a localized increase in the concentration of Ca2+. Specifically, insulin induces a rise in near-membrane Ca2+ but not the bulk Ca2+ in the myoplasm. The rise in near-membrane Ca2+ is because of an influx through channels that can be blocked by L-type Ca2+ channel inhibitors. Calcium appears to exert some of its subsequent effects via calmodulin-dependent processes as calmodulin inhibitors block the translocation of glucose transporters and other enzymes as well as the insulin-stimulated increase in glucose transport.
Bruton
J D
JD
Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
Katz
A
A
Westerblad
H
H
D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects; D002147:Calmodulin / Q000502:physiology*; D005947:Glucose / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D051379:Mice; D018485:Muscle Fibers, Skeletal / Q000187:drug effects / Q000378:metabolism; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D015398:Signal Transduction
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D002147:Calmodulin; D007328:Insulin; D005947:Glucose; D002118:Calcium