He was my "academic grandfather" (I did research in Amy Palmer's lab at CU Boulder). The number of applications of the fluorescent proteins he helped develop into research tools is staggering. The article mentions their use in cancer and HIV research, but those are just a couple of applications -- at CU we used fluorescent proteins in combination with the phenomenon of fluorescence resonance energy transfer (https://en.m.wikipedia.org/wiki/Förster_resonance_energy_tra...) to measure metal ion concentrations in various parts of the cell (my work was specifically calcium ions in mitochondria) in real-time (we were looking at amyloid precursor proteins to investigate Alzheimer's disease). It's hard to overstate how useful this research tool is. Roger will be missed.