IMPROVED EFFICIENCY SOS RECRUITMENT SYSTEM - EXPRESSION OF THE MAMMALIAN GAP REDUCES ISOLATION OF RAS GTPASE FALSE POSITIVES

The Sos recruitment system (SRS) is a novel genetic method for detecti ng protein-protein interactions, The method is based on localizing Sos , a Ras guanyl nucleotide exchange factor (GEF), to the plasma membran e through interaction between two fusion proteins, Mammalian Ras can b ypass the requirement for a functional Ras GEF and represents a predic table false positive in this system, This report demonstrates that int roduction of mammalian GTPase activating protein (mGAP) reduces the is olation of Ras false positives in SRS screens of mammalian cDNA librar ies, thereby significantly enhancing the efficiency of the system.