title: Tropomyosin binding to F-actin protects the F-actin from disassembly by brain actin-depolymerizing factor (ADF).
abstract: Brain or muscle F-actin is rapidly depolymerized to monomeric actin in vitro by actin-depolymerizing factor, a protein isolated from chick embryo brain. Binding of muscle tropomyosin to muscle F-actin protects the F-actin from depolymerization by this factor. A 8.4/1.0 molar ratio of actin subunits to tropomyosin, achieved by incubation of the F-actin with excess tropomyosin, protects 58% of the F-actin from depolymerization by excess actin-depolymerizing factor for at least 3 hr at 25 degrees C. Thus, actin-depolymerizing factor seems to be specifically directed toward actin filaments lacking tropomyosin.
mesh_terms: D051339:Actin Depolymerizing Factors; D000199:Actins / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism; D002642:Chick Embryo; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D051345:Destrin; D066298:In Vitro Techniques; D008840:Microfilament Proteins; D009132:Muscles / Q000378:metabolism; D011487:Protein Conformation / Q000187:drug effects; D011506:Proteins / Q000494:pharmacology*; D011817:Rabbits; D014335:Tropomyosin / Q000378:metabolism*
chemical_list: D051339:Actin Depolymerizing Factors; D000199:Actins; D051345:Destrin; D008840:Microfilament Proteins; D011506:Proteins; D014335:Tropomyosin