Figure 4.

Immunogold electron microscopic localization of Syn7 in MDCK cells. (A) Ultrathin cryosections were labeled with a specific affinity-purified antibody against Syn7 (anti-Syn7#1) followed by 15-nm protein A–gold. Specific labeling (arrowheads) was observed in the perinuclear region of the cell associated with multivesicular endosomes (e). (B–D) Intracellular MDCK membranes were fixed with paraformaldehyde and adsorbed to Formvar-coated grids. Membranes were then sequentially double labeled for Syn7 (15-nm protein A–gold; S7) and CI-MPR (20-nm protein A–gold; MPR) (B); Syn7 (20-nm protein A–gold; S7) and Rab7 (10-nm protein A–gold; R7) (C); or Syn7 (10-nm protein A–gold; S7) and EEA1 (15-nm protein A–gold) (D). Bar, 300 nm