Calcium-dependent muscle contraction in obliquely striated Ascaris suum muscle.
The regulatory proteins of Ascaris suum striated skeletal muscle were partially purified and characterized. A tropomyosin isoform (Mr 41K) and three troponin subunits identified as troponin T (Mr 37.5K), troponin I (Mr 25.5K) and troponin C (Mr 18.5K) were purified. Three myosin light chains (Mr 25K, 19K, and 17K) were isolated from washed Ascaris actomyosin; the 19K subunit was phosphorylated in vitro. A calcium/calmodulin-dependent myosin light chain kinase activity was identified in the muscle. In contrast to previously reported data suggesting that Ascaris obliquely striated muscle contraction is regulated by a myosin-mediated mechanism, these data indicate that all of the proteins required for actin-mediated, calcium-dependent muscle contraction are present in this tissue.
D000818:Animals; D001200:Ascaris / Q000502:physiology*; D002118:Calcium / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D009119:Muscle Contraction / Q000187:drug effects*; D009124:Muscle Proteins / Q000302:isolation & purification; D009132:Muscles / Q000187:drug effects / Q000502:physiology; D009210:Myofibrils / Q000648:ultrastructure; D009219:Myosin-Light-Chain Kinase; D009218:Myosins / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D014335:Tropomyosin / Q000378:metabolism; D014336:Troponin / Q000378:metabolism
D009124:Muscle Proteins; D014335:Tropomyosin; D014336:Troponin; D011494:Protein Kinases; D009219:Myosin-Light-Chain Kinase; D009218:Myosins; D002118:Calcium