A bright and photostable photoconvertible fluorescent protein

An improved version of the green-to-red photoconverting EosPF is presented. mEos2 is a functional fusion partner for many cellular proteins and retains the high localization precision of EosFP in super-resolution imaging. Also in this issue, Subach et al. present an inducible mCherry variant for super-resolution imaging. Photoconvertible fluorescent proteins are potential tools for investigating dynamic processes in living cells and for emerging super-resolution microscopy techniques. Unfortunately, most probes in this class are hampered by oligomerization, small photon budgets or poor photostability. Here we report an EosFP variant that functions well in a broad range of protein fusions for dynamic investigations, exhibits high photostability and preserves the ∼10-nm localization precision of its parent.