Table 2.

Density of lgp120 immunogold labelling over endosomes and lysosomes

Tf-HRP endosomes Lamin A siRNA TSG101 siRNA
Membrane (μm) 14.07 16.11
Total lgp120 particles 9 17
Particles per μm membrane 0.6 1.1
Lysosomes Lamin A siRNA TSG101 siRNA
Membrane (μm) 14.32 16.11
Total lgp120 particles 237 268
Particles per μm membrane 16.6 16.6
  • TSG101-depleted and lamin A-depleted cells were incubated with EGF and 108 anti-EGFR 10 nm gold for 30 minutes at 4°C, washed, and incubated at 37°C for a further 1 hour, with TfHRP added for the final 30 minutes. The cells were then post-fix labelled with 5 nm gold for lgp120. Measurements were made of membrane length of Tf-HRP-containing endosomes and of lysosomes (scored by morphology; heterogeneous content, and single perimeter membrane containing at least one lgp120 gold particle) in control cells (from 6 cells) and of Tf-HRP-containing multicisternal endosomes and of lysosomes from TSG101-depleted cells (6 cells; only membrane exposed to cytosol was measured, based on the assumption that antibody would be excluded from intercisternal areas). Lgp120 gold particles on measured membrane were counted.