Engineering GFP-Family Member Protiens to Achieve Novel Functions: A Class of Proteins Limited Only by the Imagination

Abstract

The Green Fluorescent Protein (GFP) has single handedly revolutionized microscopy and molecular biology. A simple search for GFP in the NCBI Pubmed database yields over 29,900 unique publications as of April 2015 demonstrating the importance and influence GFP has had on the scientific community. It is because of this impact that the 2008 Nobel Prize in Chemistry was awarded jointly to Osamu Shimomura, Martin Chalfie, and Roger Y. Tsien for their ground breaking work on the discovery and characterization of GFP family proteins. GFP has come a long way since it was first isolated from Aquorea Victoria, a bioluminescent jellyfish native to the Pacific Northwest. In the past 2 decades since it was first cloned countless variants have been engineered. There are now literally hundreds of variants of GFP family proteins with more continuously being engineered. The choice of emission colors spans the entire visible spectrum and even beyond with some reaching into the infrared wavelengths. It would be a daunting task to attempt to cover all the amazing achievements in engineering of GFP family proteins and their diverse applications. Researchers are continuously improving on the constructs available, increasing their efficiency, sensitivity, and stability. GFP family proteins have been adapted to be everything from reporters of gene expression to labels for entire organelles or even entire tissues. GFP can be used to visualize protein binding and transient protein-protein interactions. GFP can also have its fluorescence put under the direct control of a small molecule ligand paving the way for switchable and biosensor GFPs. The more one reads about GFP the more it becomes clear that the applications of this amazing protein family are still expanding at a very rapid pace. Here, I will focus on a few of what I consider the most interesting, ambitious, and novel engineering applications of the GFP family of proteins.