Preparation of membrane proteins from Drosophila embryos

INTRODUCTIONDrosophila embryos provide a unique system for the study of membrane proteins because of an extensive database in both genetics and biochemistry. Drosophila early embryos have an extraordinary peak in membrane biogenesis with a 23-fold increase in membrane area over ~45 minutes. This protocol describes purification of Drosophila membranes using equilibrium sedimentation in a sucrose density step gradient (0.5 M, 2.0 M, 2.5 M). It also includes two methods to determine the membrane association of a protein of interest: (1) alkaline wash and (2) Triton X-114 phase separation.