Figure 1.

Neomycin precipitates β- and β′-COP in cytosol from CHO cells. Cytosol from CHO cells was incubated with the indicated concentrations of neomycin for 2 h at 4°C in 100 μl of reaction buffer containing 25 mM HEPES, pH 7.4, 50 mM KCl, and 2.5 mM Mg(OAc)₂ at a final cytosol protein concentration of 1.5 mg/ml. The mixture was centrifuged and β-COP or β′-COP in the pellets or supernatants were assayed by immunoblotting as described in MATERIAL AND METHODS. (A) Detection of β-COP in pellets and supernatants by immunoblotting. (B) Quantitation of the β-COP bands in A. (C) Detection of β′-COP in pellets by immunoblotting. (D) Detection of β-COP precipitated from cytosol that was adjusted to the indicated concentrations of KCl prior to adding 1 mM neomycin.