title: Inhibition of smooth muscle myosin's activity and assembly by an anti-rod monoclonal antibody.
abstract: Monoclonal antibodies specific for the rod region can affect smooth muscle myosin's motor properties. Actin movement by phosphorylated myosin was inhibited by an antibody (LMM.4) which binds to the COOH-terminal end of the coiled-coil rod, a region thought to be involved in filament assembly. The actin-activated ATPase activity of the myosin-antibody LMM.4 complex was also reduced 10-fold at actin concentrations that gave maximal turnover rates with filamentous myosin. Metal-shadowing of the phosphorylated myosin-antibody complex at low ionic strength showed small bundles of parallel extended molecules, instead of filaments. Five other anti-rod antibodies had little or no effect on myosin's ability to act as a motor. This is the first demonstration that a muscle myosin's activity is affected by its state of assembly. A common theme that emerges from the studies on both muscle and non-muscle myosins is that assembly into a filamentous structure stimulates the activity of the individual myosin molecules.
authors: Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02254.
authors: A
authors: A
authors: Horowitz
authors: K M
authors: KM
authors: Trybus
mesh_terms: D000199:Actins / Q000378:metabolism; D000205:Actomyosin / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D005895:Gizzard, Avian / Q000378:metabolism; D015151:Immunoblotting; D007700:Kinetics; D008854:Microscopy, Electron; D009130:Muscle, Smooth / Q000378:metabolism*; D009218:Myosins / Q000302:isolation & purification / Q000378:metabolism* / Q000648:ultrastructure; D010766:Phosphorylation; D014422:Turkeys
chemical_list: D000199:Actins; D000911:Antibodies, Monoclonal; D000205:Actomyosin; D009218:Myosins