Now you see it, now you don't…or vice versa

Abstract

When researchers cloned green fluorescent protein (GFP) from Aequoria victoria nearly ten years ago, they gave us molecular biologists a bright new future. Since then, many variants of GFP have been generated from more photostable ones (pEGFP) to those with altered excitation spectra, giving us different colors (pEYFP, pECFP). Then came Discosoma red fluorescent protein (RFP) (DsRed) and Heteractis crispa far-red RFP (HcRed), with all their might. And you thought it was all over…Patterson and Lippincott-Schwartz [1xA photoactivatable GFP for selective labelling of proteins and cells. Patterson, G.H. and Lippincott-Schwartz, J. Science. 2002; 297: 1873–1877Crossref | PubMed | Scopus (970)See all References[1] now unveil a photoactivatable version of GFP, which, not surprisingly, they named PA-GFP. Although based on wild-type GFP, their T302H mutant has an initially lower minor absorbance peak at ∼400 nm, producing a stark visual contrast of nearly 100-fold under 488 nm excitation, compared to only threefold contrast produced by GFP. PA-GFP protein transfected into the cells can then be photoactivated in one subcellular location, and the movement of the protein can then be easily monitored. The authors demonstrate the success of their photoactivatable PA-GFP in observing protein dynamics across nuclear membranes, and study movement within subcellular structures such as lysosomes.This new protein will no doubt prove useful for molecular and cellular biologists alike. It can, for example, be successfully employed in combination with fluorescence resonance energy transfer (FRET)-type assays, and we should certainly expect to see more of this variant used in future studies.