Boron dipyrromethene as a fluorescent caging group for single-photon uncaging with long-wavelength visible light.

Caged compounds are useful tools for precise spatiotemporal modulation of cell functions, but in most cases uncaging requires ultraviolet (UV) light, which is cytotoxic and has limited tissue penetration. Therefore, caged compounds that can be activated by longer-wavelength light are required. Here we describe a novel photoelimination reaction of 4-aryloxy boron dipyrromethene (BODIPY) derivatives and show that BODIPY can function as a caging group for phenol groups. We developed a novel BODIPY-caged histamine compound, which is photoactivatable with blue-green visible light to stimulate cultured HeLa cells in a spatiotemporally well-controlled manner. This caging strategy is expected to be widely applicable to develop tools for probing various cellular functions.