Regulation of epidermal growth factor receptor endocytosis by wortmannin through activation of Rab5 rather than inhibition of phosphatidylinositol 3-kinase.

ABSTRACT: The involvement of phosphatidylinositol 3-kinase (PI3K) in membrane trafficking in mammalian cells has largely come from experiments with wortmannin. This compound inhibits endosome fusion in vitro, possibly by inhibiting the production of phosphatidylinositol (PtdIns)-3-P, which co-regulates EEA1 with Rab5. However, the results from wortmannin inhibition experiments performed in vivo differ significantly. We have recently shown that wortmannin enlarges endosomes containing the epidermal growth factor receptor (EGFR) and enhances the lysosomal degradation of EGFR. In this report, we demonstrate that addition of the PI3K reaction products does not suppress wortmannin-induced enlargement of EGFR-containing endosomes and enhancement of EGFR degradation. Moreover, the effects of wortmannin on

SUBMITTER: Chen X 

PROVIDER: S-EPMC1084034 | biostudies-literature | 2001 Sep

REPOSITORIES: biostudies-literature