mKO2 Fused to a Farnesylated Membrane Target
Kusabira Orange is a fluorescent protein that was isolated from the mushroom coral Fungia concinna (known in Japanese as Kusabira-Ishi). Through site-directed and random mutagenesis, researchers developed a monomeric form of the protein known as mKusabira Orange (mKO) that exhibits excellent photostability under arc lamp illumination and is approximately equivalent to EGFP in brightness. An enhanced version, mKO2, contains additional mutations that improve folding and brightness. The digital image above demonstrates the localization of a fusion between mKusabira Orange 2 and a farnesylated membrane targeting peptide. The plasma membrane, which is a universal feature of all cells, is a selectively permeable phospholipid bilayer that hosts a number of different proteins critical to cell activity, including transmembrane proteins, lipid anchored proteins, and peripheral proteins.