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Light‐Induced Tyrosine Phosphorylation of BIT in the Rat Suprachiasmatic Nucleus
Author(s) -
Nakahata Yasukazu,
Okumura Nobuaki,
Shima Takaki,
Okada Masato,
Nagai Katsuya
Publication year - 2000
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2000.0742436.x
Subject(s) - suprachiasmatic nucleus , phosphorylation , tyrosine phosphorylation , tyrosine , protein tyrosine phosphatase , proto oncogene tyrosine protein kinase src , circadian clock , biology , circadian rhythm , chemistry , medicine , microbiology and biotechnology , endocrinology , biochemistry
Abstract: Circadian changes of protein tyrosine phosphorylation in the hypothalamic suprachiasmatic nucleus have been studied using rats maintained under 12‐h light/ 12‐h dark cycles as well as constant dark conditions. We found that tyrosine phosphorylation of BIT ( b rain i mmunoglobulin‐like molecule with t yrosine‐based activation motifs), a transmembrane glycoprotein of 90‐95 kDa, was higher in the light period than in the dark period and was increased after light exposure in the dark period. Similar changes in tyrosine phosphorylation were observed under constant dark conditions, but its amplitude was weaker than that in 12‐h light/12‐h dark cycles. As the tyrosine‐phosphorylated form of BIT is able to bind to the Src homology 2 domain of a protein tyrosine phosphatase, SHP‐2, we examined association of these proteins in suprachiasmatic nucleus extracts and found that SHP‐2 was coprecipitated with BIT in parallel with its tyrosine phosphorylation. These results suggest that tyrosine phosphorylation of BIT might be involved in light‐induced entrainment of the circadian clock.