Biosensor maps localized cell activity

Abstract

A new type of fluorescent biosensor makes it possible to visualize enzymatic and cell-signaling activities occurring at highly specific locations in live cells. Such activities often occur at 100-nm-sized sites and observing them is currently difficult or impossible. For example, the diffraction limit of visible light prevents light microscopy from capturing dynamic events at sites smaller than 200 to 250 nm. Superresolution techniques such as SOFI (stochastic optical fluctuation imaging) break the diffraction limit of light microscopes. But they can image only static structures in cells, not dynamic bioactivities. Now, Jin Zhang of the University of California, San Diego, and coworkers have developed biosensors that light up cellular processes in a new way and are SOFI-detectable, down to a resolution of about 100 nm (Nat. Methods 2017, DOI: 10.1038/nmeth.4221). They discovered a new biosensing phenomenon called FLINC—Fluorescence fLuctuation INcrease by Contact—in which fluorescence fluctuations speed u...