title: EGF stimulates annexin 1-dependent inward vesiculation in a multivesicular endosome subpopulation.
abstract: Here we show that EGF and EGF receptor (EGFR) are trafficked through a subpopulation of multivesicular endosomes/bodies (MVBs) that are distinct from morphologically identical vacuoles that label for the late endosomal marker lyso-bisphosphatidic acid (LBPA). EGF stimulation increases both MVB biogenesis and inward vesiculation within EGFR-containing MVBs. Deletion of annexin 1, a substrate of EGFR tyrosine kinase, abolishes the effect of EGF stimulation on inward vesiculation. This phenotype is reversible by transfection with wild-type but not Y21F phosphorylation mutant annexin 1. Deletion of annexin 1 has no effect on EGF-stimulated MVB biogenesis, suggesting that MVB biogenesis and inward vesiculation within MVB are mediated by separate mechanisms. Loss or depletion of annexin 1 has no effect on EGF degradation and causes only a small delay in EGFR degradation, indicating that annexin 1 operates downstream of Hrs- and ESCRT-mediated sorting and is required solely for EGF-stimulated inward vesiculation. Annexin 1 accumulates on internal vesicles of MVB after EGF-stimulated inward vesiculation, suggesting that it may be required for a late stage in inward vesiculation.
authors.affiliation: Division of Cell Biology, Institute of Ophthalmology, London, UK.
authors.forename: Ian J
authors.initials: IJ
authors.lastname: White
authors.forename: Lorna M
authors.initials: LM
authors.lastname: Bailey
authors.forename: Minoo Razi
authors.initials: MR
authors.lastname: Aghakhani
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Moss
authors.forename: Clare E
authors.initials: CE
authors.lastname: Futter
mesh_terms: D000818:Animals; D017305:Annexin A1 / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D011992:Endosomes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D004815:Epidermal Growth Factor / Q000378:metabolism* / Q000494:pharmacology*; D066246:ErbB Receptors / Q000032:analysis / Q000378:metabolism*; D017353:Gene Deletion; D006801:Humans; D008246:Lysophospholipids / Q000032:analysis / Q000378:metabolism; D051379:Mice; D050178:Monoglycerides / Q000032:analysis / Q000378:metabolism; D010766:Phosphorylation; D021381:Protein Transport; D022161:Transport Vesicles / Q000378:metabolism* / Q000648:ultrastructure; D014617:Vacuoles / Q000737:chemistry
chemical_list: D017305:Annexin A1; D008246:Lysophospholipids; D050178:Monoglycerides; C012786:bis(monoacylglyceryl)phosphate; D004815:Epidermal Growth Factor; D066246:ErbB Receptors