title: D-amino acid oxidase activity is inhibited by an interaction with bassoon protein at the presynaptic active zone.
abstract: Schizophrenia is a highly heritable neuropsychiatric disorder affecting ∼1% of the world's population. Linkage and association studies have identified multiple candidate schizophrenia susceptibility genes whose functions converge on the glutamatergic neurotransmitter system. One such susceptibility gene encoding D-amino acid oxidase (DAO), an enzyme that metabolizes the NMDA receptor (NMDAR) co-agonist D-serine, has the potential to modulate NMDAR function in the context of schizophrenia. To further investigate its cellular regulation, we sought to identify DAO-interacting proteins that participate in its functional regulation in rat cerebellum, where DAO expression is especially high. Immunoprecipitation with DAO-specific antibodies and subsequent mass spectrometric analysis of co-precipitated proteins yielded 24 putative DAO-interacting proteins. The most robust interactions occurred with known components of the presynaptic active zone, such as bassoon (BSN) and piccolo (PCLO). The interaction of DAO with BSN was confirmed through co-immunoprecipitation assays using DAO- and BSN-specific antibodies. Moreover, DAO and BSN colocalized with one another in cultured cerebellar granule cells and in synaptic junction membrane protein fractions derived from rat cerebellum. The functional consequences of this interaction were studied through enzyme assay experiments, where DAO enzymatic activity was significantly inhibited as a result of its interaction with BSN. Taking these results together, we hypothesize that synaptic D-serine concentrations may be under tight regulation by a BSN-DAO complex. We therefore predict that this mechanism plays a role in the modulation of glutamatergic signaling through NMDARs. It also furthers our understanding of the biology underlying this potential therapeutic entry point for schizophrenia and other psychiatric disorders.
authors.affiliation: Neuroscience Research Unit, Pfizer Global Research and Development, Groton, Connecticut 06340.
authors.forename: Michael
authors.initials: M
authors.lastname: Popiolek
authors.affiliation: Aileron Therapeutics, Cambridge, Massachusetts, Germany.
authors.forename: John F
authors.initials: JF
authors.lastname: Ross
authors.affiliation: Neuroscience Research Unit, Pfizer Global Research and Development, Groton, Connecticut 06340.
authors.forename: Erik
authors.initials: E
authors.lastname: Charych
authors.affiliation: Neuroscience Research Unit, Pfizer Global Research and Development, Groton, Connecticut 06340.
authors.forename: Pranab
authors.initials: P
authors.lastname: Chanda
authors.affiliation: Leibniz Institute for Neurobiology, Magdenburg, Germany.
authors.forename: Eckart D
authors.initials: ED
authors.lastname: Gundelfinger
authors.affiliation: Tufts University, Boston, Massachusetts, 19486.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Moss
authors.affiliation: Neuroscience Research Unit, Pfizer Global Research and Development, Groton, Connecticut 06340,. Electronic address: nick.brandon@pfizer.com.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Brandon
authors.affiliation: Neuroscience Research Unit, Pfizer Global Research and Development, Groton, Connecticut 06340,; Merck, West Point, Pennsylvania 19486.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Pausch
mesh_terms: D000818:Animals; D002531:Cerebellum / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism; D003605:D-Amino-Acid Oxidase / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D017729:Presynaptic Terminals / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000378:metabolism; D012559:Schizophrenia / Q000235:genetics / Q000378:metabolism; D012694:Serine / Q000235:genetics / Q000378:metabolism*; D013570:Synaptic Membranes / Q000235:genetics / Q000378:metabolism*
chemical_list: C498440:BSN protein, human; C113688:Bsn protein, rat; D003598:Cytoskeletal Proteins; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; C498630:PCLO protein, human; C405514:Pclo protein, rat; D016194:Receptors, N-Methyl-D-Aspartate; D012694:Serine; C417983:DAO protein, human; D003605:D-Amino-Acid Oxidase