Cold exposure induces tyrosine phosphorylation of BIT through NMDA receptors in the rat hypothalamus.
The hypothalamus has a central role in maintaining homeostases of physiological conditions including body temperature and energy balance. To examine molecular responses to cold exposure in the hypothalamus, we examined changes in protein tyrosine phosphorylation in the suprachiasmatic nucleus of the hypothalamus after acute cold exposure in rats. It was found that brain immunoglobulin-like molecule with tyrosine-based inhibitory motifs (BIT, also called SHPS-1, SIRPalpha or p84), a transmembrane glycoprotein with two ITIM motifs, showed enhanced tyrosine phosphorylation after cold exposure. Its tyrosine phosphorylation induced by cold exposure was also found in other hypothalamic nuclei including the paraventricular nucleus, lateral hypothalamic area, ventromedial hypothalamus, and arcuate nucleus. This phosphorylation was blocked by AP-5, an NMDA receptor antagonist, indicating that it was mediated by NMDA receptors. These results suggest that BIT is involved in the mechanism of neuronal responses to cold exposure in the hypothalamus.
Taniguchi
Hiroyuki
H
Division of Protein Metabolism, Institute for Protein Research, Osaka University, 3-2, Yamadaoka, Suita, Osaka 565-0871, Japan.
Okumura
Nobuaki
N
Hamada
Juri
J
Inagaki
Miho
M
Nakahata
Yasukazu
Y
Sano
Shin-ichiro
S
Nagai
Katsuya
K
D020816:Amino Acid Motifs; D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D003080:Cold Temperature; D003208:Concanavalin A / Q000494:pharmacology; D007031:Hypothalamus / Q000378:metabolism*; D015151:Immunoblotting; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D039842:Neural Cell Adhesion Molecule L1 / Q000378:metabolism*; D010766:Phosphorylation; D011233:Precipitin Tests; D051381:Rats; D017208:Rats, Wistar; D011971:Receptors, Immunologic / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D012685:Sepharose / Q000737:chemistry; D013493:Suprachiasmatic Nucleus / Q000378:metabolism; D013696:Temperature; D013997:Time Factors; D014443:Tyrosine / Q000737:chemistry*
D000943:Antigens, Differentiation; D008562:Membrane Glycoproteins; D039842:Neural Cell Adhesion Molecule L1; D011971:Receptors, Immunologic; D016194:Receptors, N-Methyl-D-Aspartate; C501924:Sirpa protein, rat; D003208:Concanavalin A; D014443:Tyrosine; D012685:Sepharose