nArgBP2, a novel neural member of ponsin/ArgBP2/vinexin family that interacts with synapse-associated protein 90/postsynaptic density-95-associated protein (SAPAP)

J Biol Chem. 1999 Oct 22;274(43):30914-8. doi: 10.1074/jbc.274.43.30914.


Postsynaptic density (PSD)-95/synapse-associated protein (SAP) 90 and synaptic scaffolding molecule (S-SCAM) are synaptic membrane-associated guanylate kinases. Both the proteins interact with SAP90/PSD-95-associated protein (SAPAP) (also called guanylate kinase-associated protein/Dlg-associated protein). SAPAP is a protein highly enriched in the PSD fraction and may link PSD-95/SAP90 and S-SCAM to Triton X-100-insoluble structures. We found here a novel SAPAP-interacting protein, which was specifically expressed in neural tissue and was present in the postsynaptic density fraction in brain. This protein had a sorbin homology domain in the N terminus, a zinc finger motif in the middle region, and three src homology (SH) 3 domains in the C terminus and was homologous to the ponsin/ArgBP2/vinexin family proteins. We named this protein nArgBP2 because it was the most homologous to ArgBP2. nArgBP2 is a neural member of a growing family of SH3-containing proteins. nArgBP2 bound to the proline-rich region of SAPAP via its third SH3 domain and was coimmunoprecipitated with SAPAP from the extract of rat brain. Furthermore, nArgBP2 was colocalized with SAPAP at synapses in cerebellum. nArgBP2 bound to not only SAPAP but also vinculin and l-afadin, known to bind to ponsin and vinexin. nArgBP2 may be implicated in the protein network around SAPAP in the PSD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing*
  • Amino Acid Sequence
  • Animals
  • Binding Sites
  • Brain / metabolism*
  • Cloning, Molecular
  • Disks Large Homolog 4 Protein
  • Gene Expression
  • Homeodomain Proteins / metabolism
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins
  • Microfilament Proteins / metabolism
  • Molecular Sequence Data
  • Muscle Proteins / metabolism
  • Nerve Tissue Proteins / metabolism*
  • Organ Specificity
  • Rats
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / metabolism
  • SAP90-PSD95 Associated Proteins
  • Zinc Fingers
  • src Homology Domains


  • Adaptor Proteins, Signal Transducing
  • DLG4 protein, human
  • DLGAP1 protein, human
  • Disks Large Homolog 4 Protein
  • Dlg4 protein, rat
  • Homeodomain Proteins
  • Intracellular Signaling Peptides and Proteins
  • Membrane Proteins
  • Microfilament Proteins
  • Muscle Proteins
  • Nerve Tissue Proteins
  • Recombinant Proteins
  • SAP90-PSD95 Associated Proteins
  • SORBS3 protein, human
  • Sorbs2 protein, rat
  • ponsin
  • postsynaptic density proteins

Associated data

  • GENBANK/AF026505