Monkey Kidney Cells with mRuby-LC Myosin
The African green monkey kidney fibroblast cells (CV-1 line) featured in the digital video in this section were labeled with mRuby fused to light chain myosin. Mysoins are a large superfamily of motor proteins that were once thought to be found only in muscle cells. Now known to be present in virtually all eukaryotic cells, myosin isoforms hold several abilities in common, such as binding actin, transducing force, and hydrolyzing ATP. Some isoforms carry out additional specialized activities in certain tissue types.
The red fluorescent protein employed to label light chain myosin in this video, mRuby, is a monomeric derivative of eqFP611, which was originally isolated from a sea anemone. mRuby displays a large Stokes shift, similar to eqFP611, but with the advantage of improved brightness. Peak excitation and emission of mRuby occur at 558 and 605 nanometers, respectively.