Protein interaction AP-MS data for TAP-CSAG1 and TAP-CSAG2 from HEK293 cells

Ten 15 cm2 plates of HEK293 cells stably expressing TAP-vector, TAP-CSAG1, or TAP-CSAG2 were lysed with TAP lysis buffer (10% (v/v) glycerol, 50 mM HEPES-KOH pH 7.5, 100 mM KCl, 2 mM EDTA, 0.1% (v/v) NP-40, 10 mM NaF, 0.25 mM Na3VO4, 50 mM β-glyerolphosphate, 2 mM DTT, and 1X protease inhibitor cocktail (Sigma)) and cleared supernatants were bound to IgG-Sepharose beads (GE Amersham) and then washed in lysis buffer and TEV buffer (10 mM HEPES-KOH pH 8.0, 150 mM NaCl, 0.1% (v/v) NP-40, 0.5 mM EDTA, 1 mM DTT, and 1X protease inhibitor cocktail). Protein complexes were cleaved off the beads by TEV protease (Sigma) and incubated with calmodulin-Sepharose beads (GE Amersham) in calmodulin binding buffer (10 mM HEPES-KOH pH 8.0, 150 mM NaCl, 1 mM Mg acetate, 1 mM imidazole, 0.1% (v/v) NP-40, 6 mM CaCl2, 10 mM 2-mercaptoethanol) and then washed in calmodulin rinse buffer (50 mM Ammonium bicarbonate pH 8.0, 75 mM NaCl, 1 mM Mg Acetate, 1 mM Imidazole, 2 mM CaCl2) before eluted with SDS sample buffer, subjected to SDS-PAGE, and stained with GelCode Blue stain (Thermo Fisher Scientific) before protein identification by LC-MS/MS.