Analysis of smooth muscle myosin phosphorylation with native pyrophosphate gels and its application to studies on myosin phosphorylation in contracting smooth muscle.
Gizzard smooth muscle myosin, the 20,000 Mr light chain (L20) of which had been phosphorylated in vitro with a calmodulin-myosin light chain kinase system, was separated into 5 isolated bands in a pyrophosphate polyacrylamide gel. Their mobilities were in the following order: myosin with 2 unphosphorylated L20 (GM) less than myosin with 1 unphosphorylated and 1 mono-phosphorylated L20 (GMP1) less than myosin with 2 mono-phosphorylated L20 (GMP2) less than myosin with 1 mono-phosphorylated and 1 di-phosphorylated L20 (GMP3) less than myosin with 2 di-phosphorylated L20 (GMP4). We used this pyrophosphate polyacrylamide gel electrophoresis to analyze the phosphorylated state of taenia coli smooth muscle during K+-induced contraction. During the initial 2 min contraction, phosphorylated forms corresponding to GMP1 and GMP2 were detected in addition to the unphosphorylated form.
D000818:Animals; D002645:Chickens; D011756:Diphosphates; D004591:Electrophoresis, Polyacrylamide Gel; D005895:Gizzard, Avian / Q000032:analysis; D006168:Guinea Pigs; D009119:Muscle Contraction; D009130:Muscle, Smooth / Q000032:analysis* / Q000502:physiology; D009218:Myosins / Q000032:analysis*
D011756:Diphosphates; D009218:Myosins