Figure 6.

Immuno-EM of p62-positive structures in Vps24- and Tsg101-depleted cells. Cryosections of HeLa cells transfected with Vps24 (A, C, and E) or Tsg101 (B, D, and F) siRNA were incubated with antibodies against p62 (15-nm protein A gold, 10-nm in D). Membrane-free p62-positive aggregates (C and D) or p62-positive structures contained within dense clusters of vesicular-tubular elements (A and B) were detected. Vesicles with early endosomal morphology (EE) or multivesicular appearance (MVB) associated with these clusters. We also observed p62 labeling in electron-dense structures sequestered within amphisomes in cell depleted of Vps24 (E) or Tsg101 (F). The amphisomes typically consist of an electron-dense p62 positive body (E and F, arrowhead), and a multivesicular endosomal structure (E and F, arrow). Bars, 200 nm.