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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
18
pubmed:dateCreated
2001-4-30
pubmed:abstractText
The beta2 adrenergic receptor (beta2AR) undergoes desensitization by a process involving its phosphorylation by both protein kinase A (PKA) and G protein-coupled receptor kinases (GRKs). The protein kinase A-anchoring protein AKAP79 influences beta2AR phosphorylation by complexing PKA with the receptor at the membrane. Here we show that AKAP79 also regulates the ability of GRK2 to phosphorylate agonist-occupied receptors. In human embryonic kidney 293 cells, overexpression of AKAP79 enhances agonist-induced phosphorylation of both the beta2AR and a mutant of the receptor that cannot be phosphorylated by PKA (beta2AR/PKA-). Mutants of AKAP79 that do not bind PKA or target to the beta2AR markedly inhibit phosphorylation of beta2AR/PKA-. We show that PKA directly phosphorylates GRK2 on serine 685. This modification increases Gbetagamma subunit binding to GRK2 and thus enhances the ability of the kinase to translocate to the membrane and phosphorylate the receptor. Abrogation of the phosphorylation of serine 685 on GRK2 by mutagenesis (S685A) or by expression of a dominant negative AKAP79 mutant reduces GRK2-mediated translocation to beta2AR and phosphorylation of agonist-occupied beta2AR, thus reducing subsequent receptor internalization. Agonist-stimulated PKA-mediated phosphorylation of GRK2 may represent a mechanism for enhancing receptor phosphorylation and desensitization.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
4
pubmed:volume
276
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
15192-9
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
2001
pubmed:articleTitle
Regulation of membrane targeting of the G protein-coupled receptor kinase 2 by protein kinase A and its anchoring protein AKAP79.
pubmed:affiliation
Howard Hughes Medical Institute, Departments of Medicine and Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.