title: SNAP-25 gene family members differentially support secretory vesicle fusion.
abstract: Neuronal dense-core vesicles (DCVs) transport and secrete neuropeptides necessary for development, plasticity and survival, but little is known about their fusion mechanism. We show thatSnap-25-null mutant (SNAP-25 KO) neurons, previously shown to degenerate after 4 daysin vitro(DIV), contain fewer DCVs and have reduced DCV fusion probability in surviving neurons at DIV14. At DIV3, before degeneration, SNAP-25 KO neurons show normal DCV fusion, but one day later fusion is significantly reduced. To test if other SNAP homologs support DCV fusion, we expressed SNAP-23, SNAP-29 or SNAP-47 in SNAP-25 KO neurons. SNAP-23 and SNAP-29 rescued viability and supported DCV fusion in SNAP-25 KO neurons, but SNAP-23 did so more efficiently. SNAP-23 also rescued synaptic vesicle (SV) fusion while SNAP-29 did not. SNAP-47 failed to rescue viability and did not support DCV or SV fusion. These data demonstrate a developmental switch, in hippocampal neurons between DIV3 and DIV4, where DCV fusion becomes SNAP-25 dependent. Furthermore, SNAP-25 homologs support DCV and SV fusion and neuronal viability to variable extents - SNAP-23 most effectively, SNAP-29 less so and SNAP-47 ineffectively.
authors.affiliation: Department of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit (VU) Amsterdam and VU Medical Center, de Boelelaan 1085, Amsterdam 1081 HV, The Netherlands.
authors.forename: Swati
authors.identifier: http://orcid.org/0000-0002-9442-3359
authors.initials: S
authors.lastname: Arora
authors.affiliation: Department of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit (VU) Amsterdam and VU Medical Center, de Boelelaan 1085, Amsterdam 1081 HV, The Netherlands.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Saarloos
authors.affiliation: Department of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit (VU) Amsterdam and VU Medical Center, de Boelelaan 1085, Amsterdam 1081 HV, The Netherlands.
authors.forename: Robbelien
authors.identifier: http://orcid.org/0000-0003-4576-8964
authors.initials: R
authors.lastname: Kooistra
authors.affiliation: Department of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit (VU) Amsterdam and VU Medical Center, de Boelelaan 1085, Amsterdam 1081 HV, The Netherlands.
authors.forename: Rhea
authors.initials: R
authors.lastname: van de Bospoort
authors.affiliation: Department of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit (VU) Amsterdam and VU Medical Center, de Boelelaan 1085, Amsterdam 1081 HV, The Netherlands matthijs.verhage@cncr.vu.nl ruud.toonen@cncr.vu.nl.
authors.forename: Matthijs
authors.identifier: http://orcid.org/0000-0002-2514-0216
authors.initials: M
authors.lastname: Verhage
authors.affiliation: Department of Functional Genomics and Clinical Genetics, Center for Neurogenomics and Cognitive Research, Neuroscience Campus Amsterdam, Vrije Universiteit (VU) Amsterdam and VU Medical Center, de Boelelaan 1085, Amsterdam 1081 HV, The Netherlands matthijs.verhage@cncr.vu.nl ruud.toonen@cncr.vu.nl.
authors.forename: Ruud F
authors.identifier: http://orcid.org/0000-0002-9900-4233
authors.initials: RF
authors.lastname: Toonen
mesh_terms: D000818:Animals; D001692:Biological Transport; D016923:Cell Death / Q000235:genetics; D004625:Embryo, Nonmammalian; D005089:Exocytosis; D005786:Gene Expression Regulation; D005816:Genetic Complementation Test; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology; D008561:Membrane Fusion; D051379:Mice; D018345:Mice, Knockout; D009474:Neurons / Q000378:metabolism* / Q000473:pathology; D017729:Presynaptic Terminals / Q000378:metabolism* / Q000473:pathology; D061251:Primary Cell Culture; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D050766:Qb-SNARE Proteins / Q000235:genetics / Q000378:metabolism; D050767:Qc-SNARE Proteins / Q000235:genetics / Q000378:metabolism; D022142:Secretory Vesicles / Q000378:metabolism* / Q000473:pathology; D009435:Synaptic Transmission; D050825:Synaptosomal-Associated Protein 25 / Q000172:deficiency / Q000235:genetics*
chemical_list: D020033:Protein Isoforms; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; C494209:Snap25 protein, mouse; C512318:Snap47 protein, mouse; D050825:Synaptosomal-Associated Protein 25
keywords: Fusion; Hippocampal neuron; Neuropeptide vesicle; SNAP-25