The BioPlex method is a technique for studying the interaction between proteins. Using molecular biology, proteins are tagged with hemagglutinin or FLAG and expressed in cultured cells. The proteins are then affinity purified using antibodies that recognize the FLAG or HA tag and interacting proteins are identified by mass spectrometry. Screen capture from the BioPlex site (http://bioplex.hms.harvard.edu/index.php) on 23 June 2017 with permission.