Ca-ATPase isozyme expression in sarcoplasmic reticulum is altered by chronic stimulation of skeletal muscle.
Chronic stimulation of a predominantly fast skeletal muscle enhanced the expression of type I (slow muscle) Ca-ATPase and suppressed the expression of the type II (fast muscle) Ca-ATPase. Monoclonal antibodies IID8 and IIH11 against type I (slow) and type II (fast) isozymes respectively, were used to type the Ca-ATPases of the isolated SR (sarcoplasmic reticulum) by Western blots, and the Ca-ATPases of the muscle fibers by immunohistochemistry. Of the fibers from control muscles 80% stained for the type II isozyme and 20% for the type I isozyme. Following chronic stimulation all fibers stained for type I isozyme and none stained for type II isozyme. Ca-ATPase isozyme distribution in isolated SR confirmed this effect of chronic stimulation. The calcium uptake activities of homogenates of stimulated muscles were 22% of the control muscles. The Ca-ATPase and calcium-uptake activities of the isolated SR from stimulated muscles were, respectively, 32 and 45% of the control muscles.
Briggs
F N
FN
Department of Physiology, Medical College of Virginia, Richmond 23298.
Lee
K F
KF
Feher
J J
JJ
Wechsler
A S
AS
Ohlendieck
K
K
Campbell
K
K
D000818:Animals; D000911:Antibodies, Monoclonal; D000252:Calcium-Transporting ATPases / Q000096:biosynthesis* / Q000302:isolation & purification; D004285:Dogs; D004558:Electric Stimulation; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D015151:Immunoblotting; D007527:Isoenzymes / Q000096:biosynthesis* / Q000302:isolation & purification; D008970:Molecular Weight; D009132:Muscles / Q000201:enzymology / Q000294:innervation / Q000502:physiology*; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*
D000911:Antibodies, Monoclonal; D007527:Isoenzymes; D000252:Calcium-Transporting ATPases