title: Adaptor protein 2-mediated endocytosis of the β-secretase BACE1 is dispensable for amyloid precursor protein processing.
abstract: The β-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) is a transmembrane aspartyl protease that catalyzes the proteolytic processing of APP and other plasma membrane protein precursors. BACE1 cycles between the trans-Golgi network (TGN), the plasma membrane, and endosomes by virtue of signals contained within its cytosolic C-terminal domain. One of these signals is the DXXLL-motif sequence DISLL, which controls transport between the TGN and endosomes via interaction with GGA proteins. Here we show that the DISLL sequence is embedded within a longer [DE]XXXL[LI]-motif sequence, DDISLL, which mediates internalization from the plasma membrane by interaction with the clathrin-associated, heterotetrameric adaptor protein 2 (AP-2) complex. Mutation of this signal or knockdown of either AP-2 or clathrin decreases endosomal localization and increases plasma membrane localization of BACE1. Remarkably, internalization-defective BACE1 is able to cleave an APP mutant that itself cannot be delivered to endosomes. The drug brefeldin A reversibly prevents BACE1-catalyzed APP cleavage, ruling out that this reaction occurs in the endoplasmic reticulum (ER) or ER-Golgi intermediate compartment. Taken together, these observations support the notion that BACE1 is capable of cleaving APP in late compartments of the secretory pathway.
authors.affiliation: Cell Biology and Metabolism Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Yogikala
authors.initials: Y
authors.lastname: Prabhu
authors.forename: Patricia V
authors.initials: PV
authors.lastname: Burgos
authors.forename: Christina
authors.initials: C
authors.lastname: Schindler
authors.forename: Ginny G
authors.initials: GG
authors.lastname: Farías
authors.forename: Javier G
authors.initials: JG
authors.lastname: Magadán
authors.forename: Juan S
authors.initials: JS
authors.lastname: Bonifacino
mesh_terms: D033962:Adaptor Protein Complex 2 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D053829:Amyloid Precursor Protein Secretases / Q000235:genetics / Q000378:metabolism*; D016564:Amyloid beta-Protein Precursor / Q000378:metabolism*; D016282:Aspartic Acid Endopeptidases / Q000235:genetics / Q000378:metabolism*; D020126:Brefeldin A / Q000494:pharmacology; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000378:metabolism; D002966:Clathrin / Q000235:genetics / Q000378:metabolism; D004705:Endocytosis; D004721:Endoplasmic Reticulum / Q000378:metabolism; D011992:Endosomes / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting; D008856:Microscopy, Fluorescence; D009154:Mutation; D011485:Protein Binding; D055503:Protein Multimerization; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D059748:Proteolysis / Q000187:drug effects; D034622:RNA Interference; D020798:Two-Hybrid System Techniques
chemical_list: D033962:Adaptor Protein Complex 2; D016564:Amyloid beta-Protein Precursor; D002966:Clathrin; D011500:Protein Synthesis Inhibitors; D049452:Green Fluorescent Proteins; D020126:Brefeldin A; D053829:Amyloid Precursor Protein Secretases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human