Applications for Green Fluorescent Protein in Cell Signaling

The discovery of green fluorescent protein (GFP) as a naturally fluorescing protein and its subsequent modification to allow easy detection with standard fluorescent equipment such as the fluorescence-activated cell sorter (FACS) has revolutionized our ability to detect the presence of transfected proteins and to determine their location in whole cells and in organisms. GFP was found in the bioluminescent jellyfish Aequorea (1 ,2 ). It has since been modified to change its excitation and emision (3 –5 ). Expression vectors are now supplied commercially that allow proteins to be tagged easily (6 ,7 ). Furthermore, it is a small protein, only 29 kDa, and the DNA encoding it can be easily modified using polymerase chain reaction to introduce any restriction sites for any subcloning work required.