The M(r) 35,000 beta-adrenergic receptor mRNA-binding protein induced by agonists requires both an AUUUA pentamer and U-rich domains for RNA recognition.
Delineating the molecular basis for agonist-induced destabilization of mRNA of G-protein-linked receptors that contributes to receptor down-regulation is fundamental to our understanding of long-term regulation of receptors by agonist. Previously we identified a prominent, M(r) 35,000 cytosolic RNA-binding protein that (i) binds selectively to beta 1 and beta 2-adrenergic receptor mRNAs, both of which undergo agonist-induced down-regulation; (ii) does not bind either to alpha 1b-adrenergic receptor mRNA, which does not undergo agonist-induced down-regulation, or to beta-globin mRNA; (iii) displays binding to beta 2-adrenergic receptor mRNA that is selectively competed by poly(U) RNA, but not poly(A),-(C), or -(G) RNA; and (iv) its abundance varies inversely with the level of receptor mRNA, being induced by agonists that down-regulate receptor mRNA (Port, J. D., Huang, L.-y., and Malbon (1992) J. Biol. Chem. 267, 24103-24108). We demonstrate here that the binding of beta-adrenergic receptor mRNA by this protein, termed beta-ARB protein, is sensitive to competition by AU-rich domains of the 3'-untranslated regions of c-fos, c-myc, and human granulocyte-macrophage colony-stimulating factor. Using the AU-rich 3'-untranslated regions of wild-type adenovirus IVa2 mRNA and variants with defined mutations in the AUUUApentamer, AU-rich, and U-rich domains, we were able to define sequences critical to the binding of the beta 2-receptor mRNA by the beta-ARB protein. Recognition of beta-ARB protein requires not only an AUUUA destabilization pentamer, but also a flanking U-rich domain(s). Using radiolabeled 3'-untranslated regions of short-lived mRNA, we were able to identify this same M(r) 35,000 cytosolic RNA-binding protein(s), beta-ARB protein, as selective for beta 2-adrenergic receptor mRNA.
Huang
L Y
LY
Department of Pharmacology, School of Medicine, State University of New York, Stony Brook 11794-8651.
Tholanikunnel
B G
BG
Vakalopoulou
E
E
Malbon
C C
CC
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D006224:Cricetinae; D003600:Cytosol / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D016762:Genes, fos; D016259:Genes, myc; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009130:Muscle, Smooth / Q000378:metabolism; D016297:Mutagenesis, Site-Directed; D029543:Nucleocytoplasmic Transport Proteins; D015347:RNA Probes; D012333:RNA, Messenger / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism*; D011943:Receptors, Adrenergic, beta / Q000096:biosynthesis*; D012091:Repetitive Sequences, Nucleic Acid; D015183:Restriction Mapping; D013379:Substrate Specificity; D014158:Transcription, Genetic; D014649:Vas Deferens / Q000378:metabolism
D018076:DNA, Complementary; D029543:Nucleocytoplasmic Transport Proteins; D015347:RNA Probes; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011943:Receptors, Adrenergic, beta