Molecular and biochemical characterization of the mouse brain corticotropin-releasing hormone-binding protein.
A 37 kDa corticotropin-releasing hormone-binding protein (CRH-BP), distinct from the CRH receptor, is expressed in rat anterior pituitary corticotrophs and many regions of the brain, suggesting that CRH-BP may modulate the biological activity of CRH. In these studies a mouse brain CRH-BP (mCRH-BP) cDNA has been isolated and characterized. The 1666 nucleotide mCRH-BP cDNA is expressed in brain and pituitary and encodes a 322 amino acid protein that is highly homologous to human and rat CRH-BPs. Recombinant mCRH-BP, expressed in cultured mammalian cells, binds human CRH (Kd(app) = 0.56 nM and Ki(app) = 0.37 nM) and the alpha-helical (9-41) CRH antagonist (Ki(app) = 0.28 nM) with high affinity, but exhibits much weaker affinity for ovine CRH (Ki(app) = 206 nM). Recombinant mCRH-BP also blocks CRH-induced adrenocorticotropin release from AtT-20 cells. Additional biochemical characterization of the binding activity of mCRH-BP indicates that CRH-BP and CRH receptor utilize different molecular interactions to bind CRH.
Cortright
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DN
Department of Biological Chemistry, University of Michigan, Ann Arbor, USA.
Nicoletti
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A
Seasholtz
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AF
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001923:Brain Chemistry; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000494:pharmacology; D003346:Corticotropin-Releasing Hormone / Q000737:chemistry / Q000378:metabolism*; D003432:Cross-Linking Reagents; D018076:DNA, Complementary / Q000737:chemistry / Q000302:isolation & purification; D015870:Gene Expression; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D010902:Pituitary Gland / Q000737:chemistry; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011994:Recombinant Proteins / Q000378:metabolism; D017385:Sequence Homology
D002352:Carrier Proteins; D003432:Cross-Linking Reagents; D018076:DNA, Complementary; D012333:RNA, Messenger; D011994:Recombinant Proteins; C067133:corticotropin releasing factor-binding protein; D003346:Corticotropin-Releasing Hormone