TY - JOUR
T1 - Phosphorylation of myosin in permeabilized mammalian cardiac and skeletal muscle cells
AU - Sweeney, H. L.
AU - Stull, J. T.
PY - 1986
Y1 - 1986
N2 - The effect of myosin phosphorylation on tension production at <50% maximal activation by Ca2+ was examined in rabbit psoas and ventricular muscle. For psoas fibers, tension was determined at pCa 6.0, 5.8, 5.6, 5.5, and 5.4. Myosin light chain kinase (0.15 μM) and calmodulin (2 μM) were added, and the fibers were incubated at pCa 5.4, which resulted in an increase in light chain phosphorylation (P-light chain) from 5-10 to 60-75%. After 5 min, the sequence of pCa activations was repeated. An identical protocol was followed for cardiac muscle, except the activation solutions were pCa 6.2, 6.0, 5.9, 5.8, and 5.6. Phosphorylation of P-light chain increased tension in both permeabilized cardiac and skeletal muscle fibers. The effect manifested itself as a leftward shift in the pCa-tension relationship at levels below 50% maximal activation, with a decrease in the slope of the pCa-tension relationship. These results indicate that P-light chain phosphorylation affects actin-myosin interactions in cardiac and skeletal muscles at submaximal levels of Ca2+ activation.
AB - The effect of myosin phosphorylation on tension production at <50% maximal activation by Ca2+ was examined in rabbit psoas and ventricular muscle. For psoas fibers, tension was determined at pCa 6.0, 5.8, 5.6, 5.5, and 5.4. Myosin light chain kinase (0.15 μM) and calmodulin (2 μM) were added, and the fibers were incubated at pCa 5.4, which resulted in an increase in light chain phosphorylation (P-light chain) from 5-10 to 60-75%. After 5 min, the sequence of pCa activations was repeated. An identical protocol was followed for cardiac muscle, except the activation solutions were pCa 6.2, 6.0, 5.9, 5.8, and 5.6. Phosphorylation of P-light chain increased tension in both permeabilized cardiac and skeletal muscle fibers. The effect manifested itself as a leftward shift in the pCa-tension relationship at levels below 50% maximal activation, with a decrease in the slope of the pCa-tension relationship. These results indicate that P-light chain phosphorylation affects actin-myosin interactions in cardiac and skeletal muscles at submaximal levels of Ca2+ activation.
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U2 - 10.1152/ajpcell.1986.250.4.c657
DO - 10.1152/ajpcell.1986.250.4.c657
M3 - Article
C2 - 3754389
AN - SCOPUS:0022458216
SN - 0363-6143
VL - 250
SP - C657-C660
JO - American Journal of Physiology - Cell Physiology
JF - American Journal of Physiology - Cell Physiology
IS - 4 (19/4)
ER -