Basic methods to visualize actin filaments in vitro using fluorescence microscopy for observation of filament severing and bundling

Abstract

Dynamics of actin fi laments are regulated by a number of actin-binding proteins. To understand the function of an actin-binding protein, it is necessary to characterize effects of the protein on actin fi lament dynamics in vitro. This chapter describes basic microscopic methods to visualize fl uorescently labeled actin fi laments using commonly available fl uorescence microscope settings. Direct microscopic observation of actin fi laments provides strong evidence for severing or bundling of actin fi laments.