Fig. 3. BRO1 is not essential for CPY sorting. (A) Newly synthesized CPY was immunoprecipitated from the intracellular fraction (I) and the extracellular medium (E) from cells that had been pulse-labeled with [³⁵S]methionine/cysteine for 10 minutes, chased in non-radioactive medium for 30 minutes, then converted to spheroplasts. Immunoprecipitates were resolved by SDS-PAGE and examined by fluorography. p2CPY, Golgi-modified precursor CPY; mCPY, mature CPY. (B) Fluorescence microscopic localization of Vps10-GFP and FM 4-64. The arrows indicate class E compartments.