title: SAP97 promotes the stability of Nax channels at the plasma membrane.
abstract: Na(x) is a sodium-level sensor for body fluids expressed in the circumventricular organs in the brain. Na(x) has a putative PSD-95/Disc-large/ZO-1 (PDZ)-binding motif at the carboxyl (C)-terminus. Here we found that several PDZ proteins bind to Na(x) by PDZ-array overlay assay. Among them, synapse-associated protein 97 (SAP97/DLG1) was coexpressed with Na(x) in the subfornical organ. In C6 glioblastoma cells, destruction of the PDZ-binding motif of Na(x) or depletion of SAP97 resulted in a decrease in cell-surface Na(x), which was attenuated with inhibitors of endocytosis. These results indicate that SAP97 contributes to the stabilization of Na(x) channels at the plasma membrane.
authors.affiliation: Division of Molecular Neurobiology, National Institute for Basic Biology, Okazaki, Aichi, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Matsumoto
authors.forename: Akihiro
authors.initials: A
authors.lastname: Fujikawa
authors.forename: Ryoko
authors.initials: R
authors.lastname: Suzuki
authors.forename: Hidetada
authors.initials: H
authors.lastname: Shimizu
authors.forename: Kazuya
authors.initials: K
authors.lastname: Kuboyama
authors.forename: Takeshi Y
authors.initials: TY
authors.lastname: Hiyama
authors.forename: Randy A
authors.initials: RA
authors.lastname: Hall
authors.forename: Masaharu
authors.initials: M
authors.lastname: Noda
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000235:genetics / Q000378:metabolism*; D000074288:Discs Large Homolog 1 Protein; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D020868:Gene Silencing; D051528:Guanylate Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D047468:Immunoprecipitation; D017403:In Situ Hybridization; D008297:Male; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D054731:PDZ Domains; D010957:Plasmids; D034741:RNA, Small Interfering / Q000235:genetics; D013356:Subfornical Organ / Q000166:cytology / Q000378:metabolism*; D014162:Transfection; D061566:Voltage-Gated Sodium Channels / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000074288:Discs Large Homolog 1 Protein; C000614189:Dlg1 protein, mouse; D008565:Membrane Proteins; D034741:RNA, Small Interfering; C503483:Scn7a protein, mouse; D061566:Voltage-Gated Sodium Channels; D051528:Guanylate Kinases