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Association of synapse‐associated protein 90/ postsynaptic density‐95‐associated protein (SAPAP) with neurofilaments
Author(s) -
Hirao Kazuyo,
Hata Yutaka,
Deguchi Maki,
Yao Ikuko,
Ogura Misa,
Rokukawa Chiaki,
Kawabe Hiroshi,
Mizoguchi Akira,
Takai Yoshimi
Publication year - 2000
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1046/j.1365-2443.2000.00318.x
Subject(s) - neurofilament , postsynaptic density , biology , guanylate kinase , postsynaptic potential , biochemistry , synapse , protein subunit , microbiology and biotechnology , amino acid , biophysics , receptor , membrane protein , gene , membrane , immunology , immunohistochemistry , neuroscience
Background Synapse‐associated protein (SAP) 90/Postsynaptic density (PSD)‐95‐associated protein (SAPAP) (also called Guanylate kinase‐associated protein/hDLG‐associated protein) interacts with the guanylate kinase domains of PSD‐95 and synaptic scaffolding molecule (S‐SCAM) via the middle region containing 5 repeats of 14 amino acids. SAPAP also binds the recently identified proteins, nArgBP2 and synamon (also called Shank 1a), via the proline‐rich region and the C‐terminus, respectively. SAPAP is highly enriched in the Triton X‐100‐insoluble PSD fraction, and recruits PSD‐95 into the Triton X‐100‐insoluble fraction in transfected cells. We have further characterized here the Triton X‐100‐insolubility of SAPAP and tried to identify the Triton X‐100‐insoluble structures which SAPAP interacts with. Results N‐Methyl‐ d ‐aspartate receptors were recruited into the Triton X‐100‐insoluble fraction with PSD‐95 by SAPAP. The N‐terminal region of SAPAP was Triton X‐100‐insoluble, whereas the middle and C‐terminal regions were Triton X‐100‐soluble. We identified proteins interacting with 35 S‐methionine‐labelled SAPAP in the overlay assay, determined their amino acid sequences, and found them to be neurofilaments. SAPAP interacted with neurofilaments via the N‐terminal region, was co‐immunoprecipitated with neurofilaments from the rat brain, and co‐localized with neurofilaments in transfected cells. Conclusion SAPAP associates with neurofilaments via the N‐terminal region and may link various components of the PSD to neurofilaments.