A 40,000-dalton protein from Dictyostelium discoideum affects assembly properties of actin in a Ca2+-dependent manner.
A 40,000-dalton protein that affects the assembly properties of actin in a Ca2+-dependent manner has been purified from Dictyostelium discoideum. Gel filtration chromatography indicates that the native form of this protein is a monomer. A major effect of this protein is to reduce the sedimentability of F-actin in a stoichiometric fashion. Nearly complete loss of sedimentability is observed at ratios of the 40,000-dalton protein to actin of greater than 1:10. At low stoichiometries, this protein can accelerate the rate of actin assembly under certain experimental conditions. These effects of the 40,000-dalton protein on the actin assembly properties described above require calcium ion. The 40,000-dalton protein does not exert its effects by proteolyzing actin. Furthermore, peptide maps demonstrate that this protein is not a proteolytic fragment of actin.
D000199:Actins / Q000302:isolation & purification / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology*; D004023:Dictyostelium / Q000378:metabolism*; D005656:Fungal Proteins / Q000302:isolation & purification / Q000502:physiology*; D007700:Kinetics; D008970:Molecular Weight
D000199:Actins; D005656:Fungal Proteins; D002118:Calcium