title: SNX15 links clathrin endocytosis to the PtdIns3P early endosome independently of the APPL1 endosome.
abstract: Sorting nexins (SNXs) are key regulators of the endosomal network. In designing an RNAi-mediated loss-of-function screen, we establish that of 30 human SNXs only SNX3, SNX5, SNX9, SNX15 and SNX21 appear to regulate EGF receptor degradative sorting. Suppression of SNX15 results in a delay in receptor degradation arising from a defect in movement of newly internalised EGF-receptor-labelled vesicles into early endosomes. Besides a phosphatidylinositol 3-phosphate- and PX-domain-dependent association to early endosomes, SNX15 also associates with clathrin-coated pits and clathrin-coated vesicles by direct binding to clathrin through a non-canonical clathrin-binding box. From live-cell imaging, it was identified that the activated EGF receptor enters distinct sub-populations of SNX15- and APPL1-labelled peripheral endocytic vesicles, which do not undergo heterotypic fusion. The SNX15-decorated receptor-containing sub-population does, however, undergo direct fusion with the Rab5-labelled early endosome. Our data are consistent with a model in which the EGF receptor enters the early endosome following clathrin-mediated endocytosis through at least two parallel pathways: maturation through an APPL1-intermediate compartment and an alternative more direct fusion between SNX15-decorated endocytic vesicles and the Rab5-positive early endosome.
authors.affiliation: The Henry Wellcome Integrated Signalling Laboratories, School of Biochemistry, Medical Sciences Building, University of Bristol, Bristol BS8 1TD, UK.
authors.forename: Chris
authors.initials: C
authors.lastname: Danson
authors.forename: Edward
authors.initials: E
authors.lastname: Brown
authors.forename: Oliver J
authors.initials: OJ
authors.lastname: Hemmings
authors.forename: Ian J
authors.initials: IJ
authors.lastname: McGough
authors.forename: Sam
authors.initials: S
authors.lastname: Yarwood
authors.forename: Kate J
authors.initials: KJ
authors.lastname: Heesom
authors.forename: Jeremy G
authors.initials: JG
authors.lastname: Carlton
authors.forename: Juan
authors.initials: J
authors.lastname: Martin-Serrano
authors.forename: Margaret T
authors.initials: MT
authors.lastname: May
authors.forename: Paul
authors.initials: P
authors.lastname: Verkade
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Cullen
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D002966:Clathrin / Q000235:genetics / Q000378:metabolism*; D022163:Clathrin-Coated Vesicles / Q000378:metabolism*; D004705:Endocytosis; D011992:Endosomes / Q000235:genetics / Q000378:metabolism*; D066246:ErbB Receptors / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism*; D021381:Protein Transport; D058305:Sorting Nexins / Q000235:genetics / Q000378:metabolism*
chemical_list: C464801:APPL1 protein, human; D048868:Adaptor Proteins, Signal Transducing; D002966:Clathrin; D018129:Phosphatidylinositol Phosphates; C429023:SNX15 protein, human; D058305:Sorting Nexins; C055525:phosphatidylinositol 3-phosphate; D066246:ErbB Receptors
keywords: APPL1; Clathrin; Endosome; Phosphoinositide; Sorting nexin