Filamin-actin interaction. Dissociation of binding from gelation by Ca2+-activated proteolysis. Academic Article uri icon


  • Chicken gizzard filamin has been digested with purified Ca2+-activated protease. The subunits of (Mr = 250,000) of the protein are cleaved asymmetrically into two fragments, heavy merofilamin, Mr = 240,000, and light merofilamin, Mr = 9,500. Digestion is complete at substrate to enzyme ratios of 100:1 and requires Ca2+ concentrations in excess of 0.3 mM. Heavy merofilamin binds to F-actin as evidenced by cosedimentation with F-actin, by direct observation under the electron microscope, and by its ability to inhibit actin activation of heavy meromyosin ATPase. Heavy merofilamin does not form a gel when mixed with actin, except at very low concentrations of KCl. Thus, actin binding and gelation are separable activities of filamin. We speculate that Ca2+-stimulated proteolysis may play a role in the regulation of actin-filamin interactions.

published proceedings

  • J Biol Chem

author list (cited authors)

  • Davies, P. J., Wallach, D., Willingham, M. C., Pastan, I., Yamaguchi, M., & Robson, R. M.

citation count

  • 102

complete list of authors

  • Davies, PJ||Wallach, D||Willingham, MC||Pastan, I||Yamaguchi, M||Robson, RM

publication date

  • January 1978