Down-regulation of the alpha-2C adrenergic receptor: involvement of a serine/threonine motif in the third cytoplasmic loop.

ABSTRACT:

Background

The mechanisms by which alpha-2 adrenergic receptors are down-regulated following chronic exposure to agonist are not well understood. Interestingly, the human alpha-2C receptor does not down-regulate, whereas the opossum alpha-2C receptor does down-regulate. A comparison of the amino acid sequence of the third intracellular loop of these two receptors shows that the opossum alpha-2C receptor contains a potential G protein-coupled receptor kinase (GRK)phosphorylation motif (EESSTSE) with four hydroxyl residues, whereas the human alpha-2C receptor motif only contains two hydroxyl residues (DESSAAAAE). Because a similar acidic serine-rich motif (EESSSSD) in the human alpha-2 adrenergic receptor has been demonstrated to be phosphorylated by GRK and all four serines are requ

SUBMITTER: Deupree JD 

PROVIDER: S-EPMC103669 | biostudies-literature | 2002 Apr

REPOSITORIES: biostudies-literature