Interactions of actin, myosin, and an actin-binding protein of chronic myelogenous leukemia leukocytes.

摘要: Actin, myosin, and a high molecular weight actin-binding protein were purified from chronic myelogenous leukemia (CML) leukocytes. CML leukocyte actin resembled skeletal muscle other cytoplasmic actins by its subunit weight, ability to polymerize in the presence of salts, activate Mg2+-ATPase activity rabbit myosin. myosin was similar vertebrate myosins having heavy chains two light subunits. However, apparent heavy-chain Stokes radius suggested that it variably degraded during purification. Purified had average specific EDTA- AND Ca2+-activated ATPase activities 125 151 nmol Pi released/mg per min, respectively low activity. The increased 200-fold F-actin, but relative actin-activated low. like myosins, formed filaments 0.1 M KCl solutions. Reduced denatured leukocyte-actin-binding single recently described pulmonary macrophages which promotes polymerization gelation actin. Cytoplasmic extracts leukocytes prepared with ice-cold 0.34-M sucrose solutions containing Mg2+-ATP, dithiothreitol, EDTA at pH 7.0 underwent rapid when warmed 25 degrees C. Initially, gel could be liquified cooling ice-bath temperature. With time, extract gels shrunk ("contracted") into aggregates. following findings indicated promoted temperature-dependent involved contraction gels: (a) initially contained as their major polypeptide component consistent tangled thin filaments; (b) Contracted aggregates large quantities well actin; (c) temperature-dependent, reversible aggregation caused concentrations or solutions; (d) plus slowly contracted not absence myosin; (e) Rabbit antiserum against inhibited extracts. Antiserum no effect on partially curtailed