title: Phosphatidylinositol 3-kinase regulation of fluid phase endocytosis.
abstract: Endocytosis of the fluid phase marker, horse radish peroxidase, into baby hamster kidney cells is inhibited by treatment of cells with the fungal metabolite wortmannin. The IC50 of approximately 5 nM is consistent with the well-described action of wortmannin upon phosphatidylinositol (PI) 3-kinase. Analysis of the kinetics of uptake indicates a > 50% decrease in the initial rate of marker internalisation, a concomitant decrease in the volume of the early endosome and an increased efficiency of recycling of that marker which is internalised. As PI 3-kinase binds to activated growth factor receptors our data suggest that receptor activation can be coupled to receptor internalisation (down regulation) by localising PI 3-kinase stimulation of endocytosis.
authors.affiliation: Physiological Laboratory, University of Liverpool, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: Clague
authors.forename: C
authors.initials: C
authors.lastname: Thorpe
authors.forename: A T
authors.initials: AT
authors.lastname: Jones
mesh_terms: D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D004705:Endocytosis / Q000187:drug effects; D066298:In Vitro Techniques; D007295:Inositol Phosphates / Q000502:physiology; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000502:physiology*; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism; D015398:Signal Transduction; D000077191:Wortmannin
chemical_list: D000730:Androstadienes; D007295:Inositol Phosphates; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); D020794:Receptor Protein-Tyrosine Kinases; D000077191:Wortmannin