Procedure A: Preparation of the cell lysate Rinse a 60 mm culture dish of confluent cells with 10 mM Tris-HCl,PH 7.4, 0.15 M NaCl, 1 mM MnCl2 ,and 0.2 mM PMSF. Lyse the cells with 0.5ml cold buffer (10 mM Tris-HCl, PH 7.4,0.15 M NaCl, 1 mM MnCl2 ,3 mM PMSF, and 0.1 M Octyl glucoside) Maintain constant agitation for 20 minutes at 4 oC. Scrape the cells from the dish and centrifuge( 16,000xg, 4 oC) for 15 minutes,the supernatant is the "total cell lysate".
B : Immunoprecipitation Add 4 µg of antibody,400 µl of H2O,400 µg total protein to microcentrifuge tube. Vortex and incubate at 4celsius degree for 1 Hr. Add 10 µl 50% protein A : Agrose, vortex and incubate for 30 minutes at 4 oC. Centrifuge the agarose solution for 5 minutes( 16,000xg, 4 oC) and discard the supernatant. Wash with lysis buffer,by centrifuging 5 minutes (16,000xg,4 oC), repeat wash twice.
C: The crosslinking of ganglioside Add 200-400 µl 50-100 uM ganglioside (diluted in PBS from 5mM in DMSO stocking solution) to microcentrifuge tube. Add 2.5x 10,000 particles of 1 uM Fluosphere beads. Mix overnight at 4 oC with 200 µl 5mg/ml 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide. Wash with PBS, by centrifuging,repeat wash 3 times. Resuspend the bead in PBS solution.
D:The detection of protein and gangliosides binding Add 5-10 µl Fluoro-bead to microcentrifuge tube with immunoprecipitated protein. incubate 1 Hr at room temperature. Wash with PBS or lysis buffer for 3 times. Monitor by Fluoro-microscope.
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