Fluorescent phallotoxin, a tool for the visualization of cellular actin.

Abstract

A fluorescent derivative of phalloidin possessing high affinity to filamentous actin was synthesized. This compound was used for visualization of actin-containing structures in eukaryotic nonmuscle cells. Due to its low MW (1250), fixation by formaldehyde was sufficient to render the membrane permeable for the labeled peptide. Bundles of microfilaments are the predominant pattern in the flat rat kangaroo [kidney] PtK1 cells, whereas a net of concentric fibers characterizes the more spherical bovine kidney MDBK cells. Specificity of staining was confirmed by competition experiments with unlabeled phalloidin.