Early effects of denervation on Ca(2+)-handling proteins in skeletal muscle.
The adaptive response of skeletal muscle fibres depends on a variety of biological factors including loading conditions and neuromuscular activity. An extreme type of atrophy-inducing change in contractile activity is represented by the physical disconnection between the motor nerve and its respective fibre unit. Since fibre type alterations have a striking effect on the Ca(2+)-regulatory apparatus, we have investigated the fate of a key Ca(2+)-pump and essential Ca(2+)-binding proteins in extensor digitorum longus specimens two weeks after nerve crush or complete denervation. In contrast to increased levels of sarcalumenin, immunoblotting revealed that the expression of the fast SERCA1 Ca(2+)-ATPase isoform is drastically decreased and fast calsequestrin is slightly reduced. Analysis of myosin heavy chain isoforms agreed with this result and showed a fast-to-slow fibre type shifting process following denervation. Hence, changes in muscle activity appear to have a profound effect on the abundance and isoform expression pattern of Ca(2+)-handling elements.
Donoghue
Pamela
P
Department of Biology, National University of Ireland, Maynooth, Co. Kildare, Ireland.
Ribaric
Samo
S
Moran
Brendan
B
Cebasek
Vita
V
Erzen
Ida
I
Ohlendieck
Kay
K
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D009119:Muscle Contraction / Q000502:physiology*; D009121:Muscle Denervation; D018656:Muscle Fibers, Fast-Twitch / Q000502:physiology; D018657:Muscle Fibers, Slow-Twitch / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology*; D018995:Myosin Heavy Chains / Q000378:metabolism; D009409:Nerve Crush; D020033:Protein Isoforms / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D012584:Sciatic Nerve / Q000502:physiology / Q000601:surgery
C506945:Atp2a1 protein, rat; D008565:Membrane Proteins; D020033:Protein Isoforms; C070323:sarcalumenin; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D018995:Myosin Heavy Chains; D000252:Calcium-Transporting ATPases; D002118:Calcium