HeLa Cell (IMAGE) University of Montreal Caption HeLa cell expressing the proximity interaction probe BirA*-Flag-active RAC1. Actin filaments are in green and biotinylated proteins are in magenta. Credit Amélie Robert (IRCM) Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.