SAPAPs
A FAMILY OF PSD-95/SAP90-ASSOCIATED PROTEINS LOCALIZED AT POSTSYNAPTIC DENSITY*
- From ‡Takai Biotimer Project, ERATO, Japan Science and Technology Corporation, c/o JCR Pharmaceuticals Co., Ltd., 2-2-10 Murotani, Nishi-ku, Kobe 651-22 and the §Department of Molecular Biology and Biochemistry, Osaka University Medical School, Suita 565, Japan
Abstract
PSD-95/SAP90 is a member of membrane-associated guanylate kinases localized at postsynaptic density (PSD) in neuronal cells. Membrane-associated guanylate kinases are a family of signaling molecules expressed at various submembrane domains which have the PDZ (DHR) domains, the SH3 domain, and the guanylate kinase domain. PSD-95/SAP90 interacts withN-methyl-d-aspartate receptors 2A/B, Shaker-type potassium channels, and brain nitric oxide synthase through the PDZ (DHR) domains and clusters these molecules at synaptic junctions. However, neither the function of the SH3 domain or the guanylate kinase domain of PSD-95/SAP90, nor the protein interacting with these domains has been identified. We have isolated here a novel protein family consisting of at least four members which specifically interact with PSD-95/SAP90 and its related proteins through the guanylate kinase domain, and named these proteins SAPAPs (SAP90/PSD-95-AssociatedProteins). SAPAPs are specifically expressed in neuronal cells and enriched in the PSD fraction. SAPAPs induce the enrichment of PSD-95/SAP90 to the plasma membrane in transfected cells. Thus, SAPAPs may have a potential activity to maintain the structure of PSD by concentrating its components to the membrane area.
Footnotes
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↵* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
The nucleotide sequence(s) reported in this paper has been submitted to the GenBank™/EMBL Data Bank with accession number(s) U67137–67140 for SAPAPs and U53367 for PSRP1.
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↵¶ To whom correspondence should be addressed: Dept. of Molecular Biology and Biochemistry, Osaka University Medical School, Suita 565, Osaka, Japan. Tel.: 81-6-879-3410; Fax: 81-6-879-3419; E-mail:ytakai{at}molbio.med.osaka-u.ac.jp.
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↵1 The abbreviations used are: PSD, postsynaptic density; NMDA, N-methyl-d-aspartate; MAGUK, membrane-associated guanylate kinase; SAPAP, SAP90/PSD-95-associated protein; GST, glutathione S-transferase; MBP, maltose-binding protein; PAGE, polyacrylamide gel electrophoresis; PSRP1, PSD-95/SAP90-related protein 1; kb, kilobase pair(s).
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↵2 M. Irie, unpublished observation.
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- Received November 27, 1996.
- Revision received January 23, 1997.
