TY - JOUR
T1 - β1/β2-adrenergic receptor heterodimerization regulates β2-adrenergic receptor internalization and ERK signaling efficacy
AU - Lavoie, Catherine
AU - Mercier, Jean François
AU - Salahpour, Ali
AU - Umapathy, Dhiviya
AU - Breit, Andreas
AU - Villeneuve, Louis Robert
AU - Zhu, Wei Zhong
AU - Xiao, Rui Ping
AU - Lakatta, Edward G.
AU - Bouvier, Michel
AU - Hébertl, Terence E.
PY - 2002/9/20
Y1 - 2002/9/20
N2 - β1- and β2-adrenergic receptors (β1AR and β2AR) are co-expressed in numerous tissues where they play a central role in the responses of various organs to sympathetic stimulation. Although the two receptor subtypes share some signaling pathways, each has been shown to have specific signaling and regulatory properties. Given the recent recognition that many G protein-coupled receptors can form homo- and heterodimers, the present study was undertaken to determine whether the β1AR and β2AR can form dimers in cells and, if so, to investigate the potential functional consequences of such heterodimerization. Using co-immunoprecipitation and bioluminescence resonance energy transfer, we show that β1AR and β2AR can form heterodimers in HEK 293 cells co-expressing the two receptors. Functionally, β-adrenergic stimulated adenylyl cyclase activity was found to be identical in cells expressing β1AR, β2AR, or both receptors at similar levels, indicating that heterodimerization did not affect this signaling pathway. When considering ERK1/2 MAPK activity, a significant agonist-promoted activation was detected in β2AR- but not β1AR-expressing cells. Similarly to what was observed in cells expressing the β1AR alone, no β-adrenergic stimulated ERK1/2 phosphorylation was observed in cells co-expressing the two receptors. A similar inhibition of agonist-promoted internalization of the β2AR was observed upon co-expression of the β1AR, which by itself internalized to a lesser extent. Taken together, our data suggest that heterodimerization between β1AR and β2AR inhibits the agonist-promoted internalization of the β2AR and its ability to activate the ERK1/2 MAPK signaling pathway.
AB - β1- and β2-adrenergic receptors (β1AR and β2AR) are co-expressed in numerous tissues where they play a central role in the responses of various organs to sympathetic stimulation. Although the two receptor subtypes share some signaling pathways, each has been shown to have specific signaling and regulatory properties. Given the recent recognition that many G protein-coupled receptors can form homo- and heterodimers, the present study was undertaken to determine whether the β1AR and β2AR can form dimers in cells and, if so, to investigate the potential functional consequences of such heterodimerization. Using co-immunoprecipitation and bioluminescence resonance energy transfer, we show that β1AR and β2AR can form heterodimers in HEK 293 cells co-expressing the two receptors. Functionally, β-adrenergic stimulated adenylyl cyclase activity was found to be identical in cells expressing β1AR, β2AR, or both receptors at similar levels, indicating that heterodimerization did not affect this signaling pathway. When considering ERK1/2 MAPK activity, a significant agonist-promoted activation was detected in β2AR- but not β1AR-expressing cells. Similarly to what was observed in cells expressing the β1AR alone, no β-adrenergic stimulated ERK1/2 phosphorylation was observed in cells co-expressing the two receptors. A similar inhibition of agonist-promoted internalization of the β2AR was observed upon co-expression of the β1AR, which by itself internalized to a lesser extent. Taken together, our data suggest that heterodimerization between β1AR and β2AR inhibits the agonist-promoted internalization of the β2AR and its ability to activate the ERK1/2 MAPK signaling pathway.
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U2 - 10.1074/jbc.M204163200
DO - 10.1074/jbc.M204163200
M3 - Article
C2 - 12140284
AN - SCOPUS:0037144542
SN - 0021-9258
VL - 277
SP - 35402
EP - 35410
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 38
ER -