Fig. 1. Depletion of TSG101 causes intracellular retention of undegraded EGF. (A) Duplicate samples of lamin A-depleted (L) or TSG101-depleted (T) cells were lysed in SDS-PAGE sample buffer and analysed by western blotting for TSG101, VPS28, and tubulin. (B) Lamin A-depleted (upper panel) or TSG101-depleted (lower panel) HeLa cells were incubated with ¹²⁵I-EGF for 15 minutes at 37°C. After a brief wash to remove cell surface ¹²⁵I-EGF, cells were incubated at 37°C for the indicated times. Samples were analysed for degraded ¹²⁵I-EGF (circles), undegraded recycled EGF (triangles) and remaining cell-associated ¹²⁵I-EGF (squares). Note that initial binding of EGF was reduced by 27.4%±10.0% in TSG101-depleted cells. Values are means from three experiments, each performed in duplicate, ± s.e.m.