Coimmunoprecipitation of the LCB2 subunit with the LCB1 subunit and its HSN1-like mutants. After transfection of CHO-K1 cells with expression plasmids encoding wild-type and mutated cLCB1 with or without the amino-terminal FLAG-tag, cell membranes were prepared. The membranes were solubilized with 1% (wt/vol) sucrose monolaurate, and the solubilized fraction was subjected to an anti-FLAG Ab–coupled matrix. After washing of the matrix, proteins bound to the matrix were eluted by incubation in the SDS-sample buffer at 70°C for 5 minutes, and analyzed by Western blotting with anti-cLCB2 Ab as described in Methods.