Cells were lysed 48 h later with modified radioimmunoprecipitation assay buffer (RIPA buffer, 50 mM Tris - HCl, pH7.4, 150 mM NaCl, 1 % Nonidet P - 40 (NP - 40), 0.25 % sodium deoxycholic acid, 1
mM ethylenediaminetetraacetic acid (EDTA), 1 mM phenylmethylsulphonyl fluoride (PMSF), 1X Complete cocktail protease inhibitor (Roche, Penzberg, Germany)-RRB-.