Multiple pathways of rapid beta 2-adrenergic receptor desensitization.
Delineation with specific inhibitors
M. Lohse, J. Benovic, M. Caron, and R. Lefkowitz. J Biol Chem, 265 (6):
3202-11(February 1990)Lohse, M J Benovic, J L Caron, M G Lefkowitz, R J Research Support,
Non-U.S. Gov't United states The Journal of biological chemistry
J Biol Chem. 1990 Feb 25;265(6):3202-11..
Abstract
Exposure of beta-adrenergic receptors (beta ARs) to agonists causes
rapid desensitization of the receptor-stimulated adenylyl cyclase
response. Three main mechanisms have been implicated in this process:
phosphorylation of the receptors by the cAMP-dependent protein kinase
(PKA), phosphorylation by the specific agonist-dependent beta AR
kinase, and sequestration of the receptors away from the cell surface.
By applying inhibitors of these processes to digitonin-permeabilized
A431 cells we investigated their contributions to beta AR desensitization.
Each process could be selectively inhibited: PKA-dependent phosphorylation
by an inhibitor peptide (amino acids 1-24 of the heat-stable inhibitor
of PKA (PKI, beta AR kinase-dependent phosphorylation by heparin,
and sequestration by concanavalin A. In permeabilized cells, heparin
plus PKI completely blocked agonist-induced phosphorylation of the
beta ARs. Desensitization was assessed by quantitating the signal
transduction efficacy of the system. At high agonist concentrations
(approximately 1 microM) up to 70% desensitization occurred. Complete
blockade of this desensitization required the concurrent inhibition
of all three pathways. When individual pathways were blocked it could
be demonstrated that either the PKA or beta AR kinase mechanisms
alone resulted in 40-50% desensitization whereas sequestration alone
caused 20-30% desensitization. At low agonist concentrations (approximately
10 nM), the PKA pathway was selectively activated. These data indicate
that while desensitization mediated via the three different mechanisms
can occur independently, the quantitative contributions are not additive.
Such findings suggest distinct but overlapping physiological roles
for each mechanism in controlling receptor function.
Lohse, M J Benovic, J L Caron, M G Lefkowitz, R J Research Support,
Non-U.S. Gov't United states The Journal of biological chemistry
J Biol Chem. 1990 Feb 25;265(6):3202-11.
%0 Journal Article
%1 Lohse1990
%A Lohse, M. J.
%A Benovic, J. L.
%A Caron, M. G.
%A Lefkowitz, R. J.
%D 1990
%J J Biol Chem
%K *Intracellular A/pharmacology Adenylate Carcinoma, Carrier Cell Concanavalin Cyclase/metabolism Enzyme Heparin/*pharmacology Humans Inhibitors/*pharmacology Isoproterenol/*pharmacology Kinetics Line Magnesium/pharmacology Membrane Peptides Peptides/pharmacology Permeability Proteins Proteins/*pharmacology Signaling Squamous and beta/*drug effects/metabolism Receptor Adrenergic
%N 6
%P 3202-11
%T Multiple pathways of rapid beta 2-adrenergic receptor desensitization.
Delineation with specific inhibitors
%U http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=2154473
%V 265
%X Exposure of beta-adrenergic receptors (beta ARs) to agonists causes
rapid desensitization of the receptor-stimulated adenylyl cyclase
response. Three main mechanisms have been implicated in this process:
phosphorylation of the receptors by the cAMP-dependent protein kinase
(PKA), phosphorylation by the specific agonist-dependent beta AR
kinase, and sequestration of the receptors away from the cell surface.
By applying inhibitors of these processes to digitonin-permeabilized
A431 cells we investigated their contributions to beta AR desensitization.
Each process could be selectively inhibited: PKA-dependent phosphorylation
by an inhibitor peptide (amino acids 1-24 of the heat-stable inhibitor
of PKA (PKI, beta AR kinase-dependent phosphorylation by heparin,
and sequestration by concanavalin A. In permeabilized cells, heparin
plus PKI completely blocked agonist-induced phosphorylation of the
beta ARs. Desensitization was assessed by quantitating the signal
transduction efficacy of the system. At high agonist concentrations
(approximately 1 microM) up to 70% desensitization occurred. Complete
blockade of this desensitization required the concurrent inhibition
of all three pathways. When individual pathways were blocked it could
be demonstrated that either the PKA or beta AR kinase mechanisms
alone resulted in 40-50% desensitization whereas sequestration alone
caused 20-30% desensitization. At low agonist concentrations (approximately
10 nM), the PKA pathway was selectively activated. These data indicate
that while desensitization mediated via the three different mechanisms
can occur independently, the quantitative contributions are not additive.
Such findings suggest distinct but overlapping physiological roles
for each mechanism in controlling receptor function.
@article{Lohse1990,
abstract = {Exposure of beta-adrenergic receptors (beta ARs) to agonists causes
rapid desensitization of the receptor-stimulated adenylyl cyclase
response. Three main mechanisms have been implicated in this process:
phosphorylation of the receptors by the cAMP-dependent protein kinase
(PKA), phosphorylation by the specific agonist-dependent beta AR
kinase, and sequestration of the receptors away from the cell surface.
By applying inhibitors of these processes to digitonin-permeabilized
A431 cells we investigated their contributions to beta AR desensitization.
Each process could be selectively inhibited: PKA-dependent phosphorylation
by an inhibitor peptide (amino acids 1-24 of the heat-stable inhibitor
of PKA (PKI], beta AR kinase-dependent phosphorylation by heparin,
and sequestration by concanavalin A. In permeabilized cells, heparin
plus PKI completely blocked agonist-induced phosphorylation of the
beta ARs. Desensitization was assessed by quantitating the signal
transduction efficacy of the system. At high agonist concentrations
(approximately 1 microM) up to 70% desensitization occurred. Complete
blockade of this desensitization required the concurrent inhibition
of all three pathways. When individual pathways were blocked it could
be demonstrated that either the PKA or beta AR kinase mechanisms
alone resulted in 40-50% desensitization whereas sequestration alone
caused 20-30% desensitization. At low agonist concentrations (approximately
10 nM), the PKA pathway was selectively activated. These data indicate
that while desensitization mediated via the three different mechanisms
can occur independently, the quantitative contributions are not additive.
Such findings suggest distinct but overlapping physiological roles
for each mechanism in controlling receptor function.},
added-at = {2010-12-14T18:12:02.000+0100},
author = {Lohse, M. J. and Benovic, J. L. and Caron, M. G. and Lefkowitz, R. J.},
biburl = {https://www.bibsonomy.org/bibtex/2fa061ef11ebbd2f95b124a3260671e1d/pharmawuerz},
endnotereftype = {Journal Article},
interhash = {0d42199ca9eef8e82f14ca03ab0c6ca9},
intrahash = {fa061ef11ebbd2f95b124a3260671e1d},
issn = {0021-9258 (Print) 0021-9258 (Linking)},
journal = {J Biol Chem},
keywords = {*Intracellular A/pharmacology Adenylate Carcinoma, Carrier Cell Concanavalin Cyclase/metabolism Enzyme Heparin/*pharmacology Humans Inhibitors/*pharmacology Isoproterenol/*pharmacology Kinetics Line Magnesium/pharmacology Membrane Peptides Peptides/pharmacology Permeability Proteins Proteins/*pharmacology Signaling Squamous and beta/*drug effects/metabolism Receptor Adrenergic},
month = {Feb 25},
note = {Lohse, M J Benovic, J L Caron, M G Lefkowitz, R J Research Support,
Non-U.S. Gov't United states The Journal of biological chemistry
J Biol Chem. 1990 Feb 25;265(6):3202-11.},
number = 6,
pages = {3202-11},
shorttitle = {Multiple pathways of rapid beta 2-adrenergic receptor desensitization.
Delineation with specific inhibitors},
timestamp = {2010-12-14T18:22:41.000+0100},
title = {Multiple pathways of rapid beta 2-adrenergic receptor desensitization.
Delineation with specific inhibitors},
url = {http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=2154473},
volume = 265,
year = 1990
}