Photosensitive GFP mutants containing an azobenzene unnatural amino acid

The incorporation of unnatural amino acids represents a unique mechanism for the modulation of protein function. This approach has been utilized to generate photoswitchable GFP mutants, capable of demonstrating modulated fluorescence upon exposure to UV irradiation. Overall these photosensitive GFP mutants can be employed in various biosensing and diagnostic techniques to better understand protein function and processing.

Signal transduction: From the atomic age to the post-genomic era

We have come a long way in the 55 years since Edmond Fischer and the late Edwin Krebs discovered that the activity of glycogen phosphorylase is regulated by reversible protein phosphorylation. Many of the fundamental molecular mechanisms that operate in biological signaling have since been characterized and the vast web of interconnected pathways that make up the cellular signaling network has been mapped in considerable detail. Nonetheless, it is important to consider how fast this field is still moving and the issues at the current boundaries of our understanding. One must also appreciate what experimental strategies have allowed us to attain our present level of knowledge. We summarize here some key issues (both conceptual and methodological), raise unresolved questions, discuss potential pitfalls, and highlight areas in which our understanding is still rudimentary. We hope these wide-ranging ruminations will be useful to investigators who carry studies of signal transduction forward during the rest of the 21st century.