Fig. 4. Coimmunoprecipitation of Pdc and 14-3-3 protein in Blepharisma. Total cell lysates were subjected to immunoprecipitation with antibody against Pdc. The precipitated proteins in lysates from dark-adapted cells (lane 1), light-stimulated cells (lane 2) and cells incubated with okadaic acid prior to illumination (lane 3) were resolved by SDS-PAGE and immunoblotted for 14-3-3 protein. Arrows mark a coimmunoprecipitated protein of 33 kDa (lanes 1–3). Western blot analysis confirmed that this polypeptide represents a putative 14-3-3 protein (lane 4). Lower panel shows a densitometric quantification diagram of 14-3-3 protein levels in cell lysate under different experimental conditions (lysate from dark-adapted or illuminated cells and cells incubated with okadaic acid prior to illumination, respectively). The level of 14-3-3 protein in lysate from the control dark-adapted cells was taken as 100%. Bars represent the mean values ± s.e.m. of three experiments.