Filamentous actin was targeted in the culture of rat kangaroo kidney (PtK2) cells presented in the digital image above with BODIPY FL conjugated to phallacidin, a bicyclic peptide derived from a toxic mushroom. In addition, the cells were treated with the mitochondrion-selective stain MitoTracker Red CMXRos and a nuclear counterstain, TO-PRO-3 (pseudocolored cyan). Images were recorded with a 60x oil immersion objective using a zoom factor of 2.5 and sequential scanning with the 488-nanometer spectral line of an argon-ion laser, the 543-nanometer line from a green helium-neon laser, and the 633-nanometer line of a red helium-neon laser. During the processing stage, individual image channels were pseudocolored with RGB values corresponding to each of the fluorophore emission spectral profiles unless otherwise noted above.