Co-immunoprecipitation (Co-IP)

Immunoprecipitation was performed as described previously ²⁶. The cell lysates were incubated with IgG (Santa Cruz Biotechnology) and protein A/G Sepharose beads (Invitrogen) at 4ºC for 1 h. The supernatant was mixed with appropriate primary antibody overnight at 4ºC, followed by a 4 h incubation with protein A/G Sepharose beads. After washing with PBS and lysis buffer, the beads were mixed with 5 × SDS/PAGE loading buffer for Western blotting analysis.