Förster resonance energy transfer (FRET) is a widespread technology used to analyze and quantify protein interactions in multiple settings. While FRET is traditionally measured by microscopy, flow cytometry based-FRET is becoming popular within the last decade and more commonly used. Flow cytometry based-FRET offers the possibility to assess FRET in a short time-frame in a high number of cells thereby allowing stringent and statistically robust quantification of FRET in multiple samples. Furthermore, established, simple and easy to implement gating strategies facilitate the adaptation of flow cytometry based-FRET measurements to most common flow cytometers. We here summarize the basics of flow cytometry based-FRET, highlight recent novel developments in this field and emphasize on exciting future perspectives.

Inside Back Cover Caption: The cover image is based on the Research Article Native and activated antithrombin inhibits TMPRSS2 activity and SARS‐CoV‐2 infection by Lukas Wettstein et al., https://doi.org/10.1002/jmv.28124. Image Credit: Yasser Almeida‐Hernández.