title: Cell-specific expression of NADPH-dependent cytosolic 3,5,3'-triiodo-L-thyronine-binding protein (p38CTBP).
abstract: We have previously shown that cytosolic 3,5,3'-triiodo-L-thyronine (T3)-binding protein (CTBP) possesses a high affinity for T3 binding in the presence of nicotinamide adenine dinucleotide phosphate in vitro, and that p38CTBP increases intracellular content of T3, and suppresses T3-mediated transactivity. Screening of mRNA expression in 73 different human tIssues has demonstrated that p38CTBP mRNA is expressed at high levels in brain and heart. We have examined the intracellular localization and tissue-specific distribution of this protein by using a specific antibody against human p38CTBP. Western blotting and immunoprecipitation studies have shown that the antibody recognizes human p38CTBP. Interaction of p38CTBP with the antibody did not affect the T3-binding activity of p38CTBP, and its dimer formation in vitro. Western blotting analysis has shown that p38CTBP is expressed in brain and heart predominantly, similar to the distribution of mRNA. Immunohistochemical studies have demonstrated p38CTBP in neural cells and cardiac muscle cells. p38CTBP localizes in cytoplasm rather than in nuclei in neural cells. The evidence for the presence of tIssue-specific localization of p38CTBP has indicated that p38CTBP has a tIssue-specific function, such as the regulation of T3 delivery from cytoplasm to nuclei.
authors.affiliation: Department of Aging Medicine and Geriatrics, Shinshu University School of Medicine, 3-1-1, Asahi, Matsumoto, Nagano 390-8621, Japan. soutaro@hsp.md.shinshu-u.ac.jp
authors.forename: Satoru
authors.initials: S
authors.lastname: Suzuki
authors.forename: Jun-ichirou
authors.initials: J
authors.lastname: Mori
authors.forename: Mutsuhiro
authors.initials: M
authors.lastname: Kobayashi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Inagaki
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Inaba
authors.forename: Ai
authors.initials: A
authors.lastname: Komatsu
authors.forename: Koh
authors.initials: K
authors.lastname: Yamashita
authors.forename: Teiji
authors.initials: T
authors.lastname: Takeda
authors.forename: Takahide
authors.initials: T
authors.lastname: Miyamoto
authors.forename: Kazuo
authors.initials: K
authors.lastname: Ichikawa
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Hashizume
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism; D016466:CHO Cells; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D006224:Cricetinae; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009206:Myocardium / Q000166:cytology / Q000378:metabolism; D009249:NADP / Q000502:physiology*; D009417:Nerve Tissue / Q000166:cytology / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013963:Thyroid Hormones / Q000235:genetics / Q000378:metabolism*; D014018:Tissue Distribution; D000097810:Thyroid Hormone-Binding Proteins
chemical_list: D002352:Carrier Proteins; D008565:Membrane Proteins; D009249:NADP; D012333:RNA, Messenger; D013963:Thyroid Hormones; D000097810:Thyroid Hormone-Binding Proteins