Fig. 1. Immunoprecipitation and western blot of the SR Ca²⁺ ATPase. (Left) Oocytes injected with both cRNAs for the SR Ca²⁺ ATPase and the ß-subunit of the Na⁺/K⁺ ATPase (each 10 ng oocyte^–1) were incubated in modified Barth's medium at 19°C for 10 hours. The oocytes were subsequently transferred to Barth's medium containing [³⁵S]methionine and [³⁵S]cysteine, and labeled for 60 minutes. The extracts of the labeled oocytes were immunoprecipitated and the precipitates were separated by SDS-PAGE followed by autoradiography. (Right) The separated proteins in lanes 1-4 of the left panel were transferred to PVDF membrane. After washing the blotted PVDF membrane three times with 2% SDS containing 0.7% 2-mercaptoethanol at 70°C for 30 minutes, the proteins were stained with antiserum specific for the SR Ca²⁺ ATPase raised in goat. The primary antibody was detected with anti-goat secondary antibody (20,000x dilution) that was labeled with peroxidase.