Interaction of Neuronal Nitric-oxide Synthase with α1-Syntrophin in Rat Brain

• Published in: The Journal of biological chemistry Vol. 274; no. 17; p. 11736
• Main Authors: Akiko Hashida-Okumura, Nobuaki Okumura, Akihiro Iwamatsu, Ruud M. Buijs, Herms J. Romijn, Katsuya Nagai
• Format: Journal Article
• Language: English
• Published: American Society for Biochemistry and Molecular Biology 23.04.1999
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.274.17.11736

Neuronal nitric-oxide synthase (nNOS) has a PSD-95/Dlg/ZO-1 (PDZ) domain that can interact with multiple proteins. nNOS has been known to interact with PSD-95 and a related protein, PSD-93, in brain and with α1-syntrophin in skeletal muscle in mammals. In this study, we have purified an nNOS-interacting protein from bovine brain using an affinity column made of Sepharose conjugated with glutathione S -transferase-rat nNOS fusion protein and identified it as α1-syntrophin by microsequencing. Immunostaining of primary cultures of rat embryonic brain neuronal cells with antibodies against these proteins showed that nNOS and α1-syntrophin were colocalized in neuronal cell bodies and neurites. Immunohistochemical analysis indicated that the nNOS- and α1-syntrophin-like immunoreactive substances were highly expressed in the rat hypothalamic suprachiasmatic nucleus (SCN) and paraventricular nucleus. In the SCN, nNOS- and α1-syntrophin-like immunoreactive substances were colocalized in the same neurons as detected by confocal microscopy. These results indicate that nNOS in brain interacts with α1-syntrophin in specific neurons of the SCN and paraventricular nucleus and that this interaction might play a physiological role in functions of these neurons.