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

TLDR

The fluorescent phalloidin derivative was used to visualize actin in eukaryotic nonmuscle cells; its low molecular weight allowed formaldehyde fixation to permeabilize membranes, and specificity was confirmed by competition with unlabeled phalloidin. The derivative binds filamentous actin with high affinity, revealing that flat rat kangaroo PtK1 cells display bundled microfilaments while spherical bovine kidney MDBK cells show a net of concentric fibers.

Abstract

A fluorescent derivative of phalloidin has been synthesized possessing high affinity to filamentous actin. This compound was used for visualization of actin-containing structures in eukaryotic nonmuscle cells. Due to its low molecular weight (1250), fixation for formaldehyde was sufficient to render the membrane permeable for the labeled peptide. Bundles of microfilaments are the predominant pattern in the flat rat kangaroo 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.