Interaction of filamin with f-actin in solution.

Abstract

Filamin is a major high MW protein in smooth muscle which was recently identified and isolated. Highly purified chicken gizzard filamin and muscle F-actin react in solution formed aggregates containing both proteins. These aggregates coagulated and contracted into a dense gel in the absence of MgATP or CaATP. Immunofluorescence and EM studies suggested that the F-actin filaments were collected into fiber bundles and a crosslinked fiber meshwork by the binding of filamin molecules. The function of filamin in intact cells may be to regulate the ultrastructural state of F-actin filaments in a variety of dynamic cellular processes.