title: Zinc transporter-1: a novel NMDA receptor-binding protein at the postsynaptic density.
abstract: Zinc (Zn(2+) ) is believed to play a relevant role in the physiology and pathophysiology of the brain. Hence, Zn(2+) homeostasis is critical and involves different classes of molecules, including Zn(2+) transporters. The ubiquitous Zn(2+) transporter-1 (ZNT-1) is a transmembrane protein that pumps cytosolic Zn(2+) to the extracellular space, but its function in the central nervous system is not fully understood. Here, we show that ZNT-1 interacts with GluN2A-containing NMDA receptors, suggesting a role for this transporter at the excitatory glutamatergic synapse. First, we found that ZNT-1 is highly expressed at the hippocampal postsynaptic density (PSD) where NMDA receptors are enriched. Two-hybrid screening, coimmunoprecipitation experiments and clustering assay in COS-7 cells demonstrated that ZNT-1 specifically binds the GluN2A subunit of the NMDA receptor. GluN2A deletion mutants and pull-down assays indicated GluN2A(1390-1464) domain as necessary for the binding to ZNT-1. Most importantly, ZNT-1/GluN2A complex was proved to be dynamic, since it was regulated by induction of synaptic plasticity. Finally, modulation of ZNT-1 expression in hippocampal neurons determined a significant change in dendritic spine morphology, PSD-95 clusters and GluN2A surface levels, supporting the involvement of ZNT-1 in the dynamics of excitatory PSD. Zn(2+) transporter-1 (ZNT-1) pumps cytosolic Zn(2+) to the extracellular space, but its function in the central nervous system is not fully understood. We show that ZNT-1 interacts with GluN2A-containing NMDA receptors at the glutamatergic synapse. Most importantly, ZNT-1/GluN2A complex is regulated by induction of synaptic plasticity. Modulation of ZNT-1 expression in hippocampal neurons determined a shrinkage of dendritic spines and a reduction of GluN2A surface levels supporting the involvement of ZNT-1 in the dynamics of the excitatory synapse.
authors.affiliation: DiSFeB, Dipartimento di Scienze Farmacologiche e Biomolecolari, Università degli Studi di Milano, Milano, Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Mellone
authors.forename: Silvia
authors.initials: S
authors.lastname: Pelucchi
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Alberti
authors.forename: Armando A
authors.initials: AA
authors.lastname: Genazzani
authors.forename: Monica
authors.initials: M
authors.lastname: Di Luca
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Gardoni
mesh_terms: D000818:Animals; D019556:COS Cells; D002118:Calcium / Q000378:metabolism; D027682:Cation Transport Proteins / Q000378:metabolism*; D002522:Chlorocebus aethiops; D003712:Dendrites / Q000648:ultrastructure; D019706:Excitatory Postsynaptic Potentials / Q000502:physiology; D005260:Female; D006624:Hippocampus / Q000166:cytology / Q000378:metabolism; D017136:Ion Transport; D008297:Male; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009473:Neuronal Plasticity; D057907:Post-Synaptic Density / Q000378:metabolism*; D011247:Pregnancy; D061251:Primary Cell Culture; D025941:Protein Interaction Mapping; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D015032:Zinc / Q000378:metabolism
chemical_list: D002118:Calcium; D027682:Cation Transport Proteins; D009419:Nerve Tissue Proteins; D016194:Receptors, N-Methyl-D-Aspartate; D015032:Zinc; C121001:NR2B NMDA receptor; C092392:Slc30a1 protein, rat
keywords: NMDA receptor; ZNT-1; dendritic spine; postsynaptic density; proteinߝprotein interaction