Method for the Rapid Screening of Drug Candidates Using Single‐Protein Tracking in a Living Cell

Screening drug candidates rapidly is the first step for developing new pharmaceutical drugs. One of the most promising ways to reduce the number of screening steps and cost is to directly use living cells for screening instead of using purified target proteins. Compounds screened using living cells will have increased biological activity compared to those screened with in vitro assays. Here, we report a robust method for screening drug candidates in living cells based on single‐protein imaging. We employed single‐protein tracking to observe the variation in the diffusion coefficient of membrane proteins treated with the candidate compounds. The diffusion coefficient shift was introduced as a criterion for selecting the potential candidate compounds. We tested three different membrane proteins, epidermal growth factor receptor, ErbB2, and ErbB3, and found effective natural compounds for each protein. The screening method we introduce will be widely used for screening potential drug candidates using living cells. Screening drug candidates is the first step for developing new drugs. Cell‐based assays have multiple advantages compared with in vitro assays because cell‐based assays enable the screening of compounds that have biological activities. Here, we report a robust method for screening drug candidates in living cells. We employed single‐protein tracking to observe the variation in the diffusion coefficient of membrane proteins.