Photocleavable Fluorescent Membrane Tension Probes: Fast Release with Spatiotemporal Control in Inner Leaflets of Plasma Membrane, Nuclear Envelope, and Secretory Pathway

Mechanosensitive flipper probes are attracting interest as fluorescent reporters of membrane order and tension in biological systems. We introduce PhotoFlippers, which contain a photocleavable linker and an ultralong tether between mechanophore and various targeting motifs. Upon irradiation, the original probe is released and labels the most ordered membrane that is accessible by intermembrane transfer. Spatiotemporal control from photocleavable flippers is essential to access open, dynamic or elusive membrane motifs without chemical or physical interference. For instance, fast release with light is shown to place the original small-molecule probes into the innermost leaflet of the nuclear envelope to image changes in membrane tension, at specific points in time of membrane trafficking along the secretory pathway, or in the inner leaflet of the plasma membrane to explore membrane asymmetry. These results identify PhotoFlippers as useful chemistry tools to enable research in biology.

Automated summary

Mechanosensitive flipper probes, such as PhotoFlippers, containing a photocleavable linker and an ultralong tether, are able to release and label the most ordered membrane accessible by intermembrane transfer upon irradiation. This spatiotemporal control is essential for accessing open, dynamic or elusive membrane motifs without chemical or physical interference. PhotoFlippers have been shown to be useful chemistry tools for studying changes in membrane tension, membrane trafficking, and membrane asymmetry in biological systems.