screw-cap vial containing pink-colored liquid that is being withdrawn using a pipette

This protocol provides general instructions for labeling F-actin in fixed and permeabilized cells. Actin is one of the most abundant proteins found in cells and can be labeled with a fluorophore very easily when the monomers form a certain type of microfilament, referred to as F-actin. When phalloidin, a molecule that binds F-actin, is conjugated to a fluorophore, it becomes a very useful tool for cell biologists who are using fluorescence microscopy to study their cells. Labeling F-actin can help show the overall shape and structure of the cell and provide context for other fluorescent labels.

Download this protocol

Protocol tip
If you’re using fluorescent phalloidin to visualize actin in your experiment, you’ll get better results if you perm for 20 minutes instead of 15.
What you need
  • Cells that have been fixed and permeabilized (See Fix, Perm, and Block protocol)
  • Phosphate-buffered saline (PBS)
  • Phalloidin conjugated to fluorophore
  • Fluorescence microscope with filter set matched to your fluorophore


F-actin dyes—basic labeling protocol

  • For fixed and permeabilized cells
  • Can be used before or after immunolabeling
  • The volumes given in this protocol are good for a single well in a 6-well vessel or a single 35 mm vessel

1Prepare 1 mL F-actin staining solution in PBS from conjugated fluorophore. Phalloidins are typically very water soluble and stain F-actin at 100–200 nM concentrations. If you are optimizing for dye concentration, you will need to prepare a staining solution for each concentration you want to test.
2Remove PBS from fixed and permeabilized cells.
3Add 1 mL of staining solution.
4Incubate for 20 minutes at room temperature.
5Remove dye solution.
6Wash 3 times with PBS. Learn how to wash 
7Image cells.
8Optional: To preserve your sample for long-term storage, you can also mount your sample in mounting medium. Before you start your staining experiment, it’s a good idea to check that your fluorophores are compatible with the mounting medium you want to use.

仅供科研使用,不可用于诊断目的。