title: Cloning and characterization of E-dlg, a novel splice variant of mouse homologue of the Drosophila discs large tumor suppressor binds preferentially to SAP102.
abstract: Membrane-associated guanylate kinases (MAGUKs) act as scaffolds to coordinate signaling events through their multiple domains at the plasma membrane. The MAGUK SH3 domain is noncanonical and its function remains unclear. To identify potential binding partners of MAGUK SH3, the synapse-associated protein 102 (SAP102) SH3 domain was used as bait in a yeast two-hybrid screen of a mouse embryonic cDNA library. A mouse homologue of the Drosophila discs large tumor suppressor (Dlg, also known as SAP97) bound preferentially to SAP102 SH3. The 4347bp cDNA sequence encoded an 893 amino acid protein with 94% identity to mouse SAP97. A deleted region (33-aa) strongly suggests this is a novel splice variant, which we call Embryonic-dlg/SAP97 (E-dlg). The interaction of SAP102 and E-dlg was confirmed in mammalian cells. E-dlg can also bind to potassium channel Kv1.4 in a pull-down assay. E-dlg was highly expressed in embryonic and some adult mouse tissues, such as brain, kidney, and ovary. Furthermore, in situ hybridization showed that E-dlg was mostly expressed in olfactory bulb and cerebellum.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA. maop@ohsu.edu
authors.forename: Peizhong
authors.initials: P
authors.lastname: Mao
authors.forename: Yuan-Xiang
authors.initials: YX
authors.lastname: Tao
authors.forename: Masahiro
authors.initials: M
authors.lastname: Fukaya
authors.forename: Feng
authors.initials: F
authors.lastname: Tao
authors.forename: Dechun
authors.initials: D
authors.lastname: Li
authors.forename: Masahiko
authors.initials: M
authors.lastname: Watanabe
authors.forename: Roger A
authors.initials: RA
authors.lastname: Johns
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000378:metabolism; D000074288:Discs Large Homolog 1 Protein; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D016147:Genes, Tumor Suppressor; D051528:Guanylate Kinases; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D009830:Olfactory Bulb / Q000166:cytology / Q000378:metabolism; D011485:Protein Binding; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D014018:Tissue Distribution; D020798:Two-Hybrid System Techniques; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000074288:Discs Large Homolog 1 Protein; C000614189:Dlg1 protein, mouse; D029721:Drosophila Proteins; D008565:Membrane Proteins; D009479:Neuropeptides; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; C491075:Dlgh3 protein, mouse; D051528:Guanylate Kinases