title: Sorting and activity-dependent secretion of BDNF require interaction of a specific motif with the sorting receptor carboxypeptidase e.
abstract: Activity-dependent secretion of BDNF is important in mediating synaptic plasticity, but how it is achieved is unclear. Here we uncover a sorting motif receptor-mediated mechanism for regulated secretion of BDNF. X-ray crystal structure analysis revealed a putative sorting motif, I(16)E(18)I(105)D(106), in BDNF, which when mutated at the acidic residues resulted in missorting of proBDNF to the constitutive pathway in AtT-20 cells. A V20E mutation to complete a similar motif in NGF redirected a significant proportion of it from the constitutive to the regulated pathway. Modeling and binding studies showed interaction of the acidic residues in the BDNF motif with two basic residues in the sorting receptor, carboxypeptidase E (CPE). (35)S labeling experiments demonstrated that activity-dependent secretion of BDNF from cortical neurons was obliterated in CPE knockout mice. Thus, we have identified a mechanism whereby a specific motif I(16)E(18)I(105)D(106) interacts with CPE to sort proBDNF into regulated pathway vesicles for activity-dependent secretion.
authors.affiliation: Section on Cellular Neurobiology, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Lou
authors.forename: Soo-Kyung
authors.initials: SK
authors.lastname: Kim
authors.forename: Eugene
authors.initials: E
authors.lastname: Zaitsev
authors.forename: Chris R
authors.initials: CR
authors.lastname: Snell
authors.forename: Bai
authors.initials: B
authors.lastname: Lu
authors.forename: Y Peng
authors.initials: YP
authors.lastname: Loh
mesh_terms: D020816:Amino Acid Motifs / Q000502:physiology; D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D019208:Brain-Derived Neurotrophic Factor / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D043423:Carboxypeptidase H / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D002490:Central Nervous System / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism; D018360:Crystallography, X-Ray; D005260:Female; D006624:Hippocampus / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics; D010902:Pituitary Gland / Q000378:metabolism; D017729:Presynaptic Terminals / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D021381:Protein Transport / Q000502:physiology; D009435:Synaptic Transmission / Q000502:physiology*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D043423:Carboxypeptidase H