Signal Transduction by Adrenergic Receptors 
newly synthesized receptors that have not under- 
gone the post-translational processing necessary 
to produce functional protein. We hope to iden- 
tify the requisite cytosolic and membrane factors. 
Cellular Biology of /32-Adrenergic Receptors 
-Following prolonged exposure to catechol- 
amines, the /32-adrenergic receptor becomes de- 
sensitized and is less efficient in activating adeny- 
lyl cyclase. Several mechanisms contribute to the 
process of desensitization, including receptor 
phosphorylation and the removal of receptors 
from the plasma membrane. A great deal has been 
learned about the role here of phosphorylation, 
but the mechanisms for receptor removal are 
poorly understood. We have obtained antibodies 
to the /Sj-adrenergic receptor and are using them 
to characterize the process of agonist-mediated 
receptor internalization. We hope to learn about 
the molecular mechanism by which these ago- 
nist-occupied receptors are identified and tar- 
geted, either for reversible sequestration into an 
endosomal compartment or for destruction. 
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