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" Turkey beta-adrenergic receptors: "
F. Del Toro, Jr.
R. A. Nicholas
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Latin Dissertation
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| Language of Document
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English
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| Record Number
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1104008
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| Doc. No
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TLpq304439660
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| Main Entry
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F. Del Toro, Jr.
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R. A. Nicholas
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| Title & Author
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Turkey beta-adrenergic receptors:\ F. Del Toro, Jr.R. A. Nicholas
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| College
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The University of North Carolina at Chapel Hill
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| Date
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1998
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| student score
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1998
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| Degree
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Ph.D.
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| Page No
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134-134 p.
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| Abstract
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The mammalian usd\betausd-AR family has three well-characterized subtypes, the usd\beta\sb1usd-, usd\beta\sb2usd-, and usd\beta\sb3usd-adrenergic receptors. Recent cloning of a novel turkey usd\betausd-adrenergic receptor (usd\betausd-AR), called the usd\beta\sb{\rm 4c}usd-AR, has suggested the possibility of the existence of an additional mammalian usd\betausd-AR. We utilized PCR, Southern blot analysis, and library screening in an effort to clone a potential human homologue of the turkey usd\beta\sb{\rm 4c}usd-AR. Screening of two human genomic libraries resulted in the isolation of 29 clones encoding human usd\betausd-ARs: 19 usd\beta\sb1usd-AR clones, 3 usd\beta\sb2usd-AR clones, and 7 usd\beta\sb3usd-AR clones. In addition, two clones encoding the 5HT1a receptor were isolated. Since all of the known usd\betausd-AR genes were cloned by this method, but no usd\beta\sb{\rm 4c}usd-AR homologue, these studies suggest that a mammalian homologue of the turkey usd\beta\sb{\rm 4c}usd-AR does not exist. Turkeys also express a usd\beta\sb2usd-AR with 82% identity to the human usd\beta\sb2usd-AR that terminates 16 aminoacids earlier than the human usd\beta\sb2usd-AR. Furthermore, the turkey usd\beta\sb2usd-AR lacks multiple serine and threonine residues in its carboxy-terminus, suggesting a potential alteration in the desensitization properties of the turkey receptor compared to human. We expressed both turkey and human usd\beta\sb2usd-ARs in the same cell line at similar receptor densities and showed that the affinities of a series of agonists and antagonists were nearly identical at both receptors. Functionally, both turkey and human usd\beta\sb2usd-ARs couple to elevations in cellular cyclic AMP and their propensities to undergo both homologous and long-term desensitization were nearly identical. These data indicate that the desensitization properties of the turkey and human usd\beta\sb2usd-adrenergic receptors are very similar, even though the turkey usd\beta\sb2usd-AR lacks multiple phosphorylation sites.
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| Subject
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Adrenergic
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Beta adrenergic receptor
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Biological sciences
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Health and environmental sciences
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Pharmacology
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Turkey receptor
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