A new 120,000-dalton actin-binding protein isolated from Dictyostelium discoideum increases the initial rate of actin polymerization and decreases the critical concentration of actin at steady state.
A novel 120,000-dalton actin-binding protein from Dictyostelium discoideum was identified as a regulator of actin cytoskeleton assembly.
Abstract A new actin binding protein has been purified to homogeneity from amoebae of Dictyostelium discoideum. This protein is a single polypeptide with a molecular weight of 120,000 upon sodium dodecyl sulfate gel electrophoresis. It is soluble and trypsin‐sensitive, contains no carbohydrate, increases the viscosity and sedimentation rate of F actin, and inhibits the actin‐stimulated Mg ATPase of rabbit muscle heavy meromyosin. The interaction of 120,000‐dalton protein with F actin is not inhibited by millimolar ATP, pyrophosphate, or micromolar calcium. The 120,000‐dalton actin binding protein increases the initial rate of actin polymerization and decreases the critical concentration of actin at steady state. These properties demonstrate that 120,000‐dalton protein from Dictyostelium discoidum is not a myosinlike protein. Rather, this protein is probably involved in regulating the assembly of the actin cytoskeletion.
Condeelis et al. (Fri,) reported a other. A new 120,000-dalton actin-binding protein isolated from Dictyostelium discoideum increases the initial rate of actin polymerization and decreases the critical concentration of actin at steady state.