Pharmacological Characterization and Cross Talk of α<sub>1A</sub>- and α<sub>1B</sub>-Adrenoceptors Coexpressed in Human Embryonic Kidney 293 Cells

Israilova, Malika; Tanaka, Takashi; Suzuki, Fumiko; Morishima, Shigeru; Muramatsu, Ikunobu

doi:10.1124/jpet.103.061796

Cited by 29 publications

(19 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We have found that ␣ 1B -/␣ 1D -AR heterodimers stimulate greater maximal NE responses relative to ␣ 1B -ARs and ␣ 1D -AR expressed alone, suggesting that this heterodimer may act as a high-efficacy complex. This is similar to previous findings on ␣ 1A -/␣ 1B -AR heterodimerization in which NE responses were ϳ10-fold greater in HEK293 cells coexpressing ␣ 1A -and ␣ 1B -ARs (Israilova et al, 2004). In addition, a recent study using ␣ 1 -AR knockout mice found that ␣ 1D -AR and ␣ 1D -/␣ 1B -AR knockout mice had a significant decrease in mean arterial blood pressure, whereas ␣ 1B -AR knockout mice did not, suggesting that ␣ 1D -/␣ 1B -ARs may act cooperatively to regulate blood pressure (Hosoda et al, 2005).…”

Section: Discussionsupporting

confidence: 81%

Heterodimers of α_1B- and α_1D-Adrenergic Receptors Form a Single Functional Entity

et al. 2005

View full text Add to dashboard Cite

Heterologous expression of ␣ 1D -adrenergic receptors (␣ 1D -ARs) in most cell types results in intracellular retention and little or no functionality. We showed previously that heterodimerization with ␣ 1B -ARs promotes surface localization of ␣ 1D -ARs. Here, we report that the ␣ 1B -/␣ 1D -AR interaction has significant effects on the pharmacology and signaling of the receptors, in addition to the effects on trafficking described previously. Upon coexpression of ␣ 1B -ARs and epitope-tagged ␣ 1D -ARs in both human embryonic kidney 293 and DDT 1 MF-2 cells, ␣ 1D -AR binding sites were not detectable with the ␣ 1D -AR selective antagonist 8-[2-(4-(2-methoxyphenyl)piperazin-1-yl)ethyl]-8-azaspiro [4,5]decane-7,9-dione (BMY 7378), despite the ability to detect ␣ 1D -AR protein using confocal microscopy, immunoprecipitation, and a luminometer cell-surface assay. However, the ␣ 1B -AR-selective mutant F18A conotoxin showed a striking biphasic inhibition in ␣ 1B /␣ 1D -AR-expressing cells, revealing that ␣ 1D -ARs were expressed but did not bind BMY 7378 with high affinity. Studies of norepinephrine-stimulated inositol phosphate formation showed that maximal responses were greatest in ␣ 1B /␣ 1D -AR-coexpressing cells. Stable coexpression of an uncoupled mutant ␣ 1B -AR (⌬12) with ␣ 1D -ARs resulted in increased responses to norepinephrine. However, Schild plots for inhibition of norepinephrine-stimulated inositol phosphate formation showed a single low-affinity site for BMY 7378. Thus, our findings suggest that ␣ 1B /␣ 1D -AR heterodimers form a single functional entity with enhanced functional activity relative to either subtype alone and a novel pharmacological profile. These data may help to explain why ␣ 1D -ARs are often pharmacologically undetectable in native tissues when they are coexpressed with ␣ 1B -ARs.

show abstract

Section: Discussionsupporting

confidence: 81%

Heterodimers of α_1B- and α_1D-Adrenergic Receptors Form a Single Functional Entity

et al. 2005

View full text Add to dashboard Cite

show abstract

“…Accumulating evidence also indicates that heteromerization might affect signalling pathways regulated by a given protomer. For example, a synergistic increase of the receptor-mediated signalling was observed for the adrenergic a 1A AR-a 1B AR and the muscarinic M 2 R-M 3 R heterodimers (Hornigold et al, 2003;Israilova et al, 2004;Fuxe et al, 2005). On the other hand, G protein signalling might be attenuated upon heteromerization, as has been reported for the opiate MOR-DOR, the a 2A AR-MOR and the adenosinedopamine A 2A R-D 2 R heterodimers (Gomes et al, 2000;Jordan et al, 2003).…”

mentioning

confidence: 77%

Heterodimerization of serotonin receptors 5-HT1A and 5-HT7 differentially regulates receptor signalling and trafficking

Renner

Zeug

Woehler

et al. 2012

Journal of Cell Science

166

157

View full text Add to dashboard Cite

SummarySerotonin receptors 5-HT 1A and 5-HT 7 are highly coexpressed in brain regions implicated in depression. However, their functional interaction has not been established. In the present study we show that 5-HT 1A and 5-HT 7 receptors form heterodimers both in vitro and in vivo. Foerster resonance energy transfer-based assays revealed that, in addition to heterodimers, homodimers composed either of 5-HT 1A or 5-HT 7 receptors together with monomers coexist in cells. The highest affinity for complex formation was obtained for the 5-HT 7 -5-HT 7 homodimers, followed by the 5-HT 7 -5-HT 1A heterodimers and 5-HT 1A -5-HT 1A homodimers. Functionally, heterodimerization decreases 5-HT 1A -receptor-mediated activation of G i protein without affecting 5-HT 7 -receptor-mediated signalling. Moreover, heterodimerization markedly decreases the ability of the 5-HT 1A receptor to activate G-protein-gated inwardly rectifying potassium channels in a heterologous system. The inhibitory effect on such channels was also preserved in hippocampal neurons, demonstrating a physiological relevance of heteromerization in vivo. In addition, heterodimerization is crucially involved in initiation of the serotonin-mediated 5-HT 1A receptor internalization and also enhances the ability of the 5-HT 1A receptor to activate the mitogen-activated protein kinases. Finally, we found that production of 5-HT 7 receptors in the hippocampus continuously decreases during postnatal development, indicating that the relative concentration of 5-HT 1A -5-HT 7 heterodimers and, consequently, their functional importance undergoes pronounced developmental changes.

show abstract

“…With respect to the signaling pathway of ␣ 1 -AR, previous studies have suggested that ␣ 1B -AR may control the receptor density and protein expression of ␣ 1A -AR by synergism and/or cross talk of the signaling pathways (16,37). Although it is believed that all ␣ 1 -AR subtypes are coupled to the Gq-protein (42), a study with ␣ 1AB -KO mice suggested the existence of distinct signaling pathways of extracellular signaling-regulated kinase via ␣ 1A -AR and of protein kinase C via ␣ 1B -AR in postnatal cardiac hypertrophy (20).…”

Section: Discussionmentioning

confidence: 99%

Blockade of both α_1A- and α_1B-adrenergic receptor subtype signaling is required to inhibit neointimal formation in the mouse femoral artery

Hosoda¹,

Hiroyama²,

Sanbe³

et al. 2007

American Journal of Physiology-Heart and Circulatory Physiology

View full text Add to dashboard Cite

show abstract

Pharmacological Characterization and Cross Talk of α_1A- and α_1B-Adrenoceptors Coexpressed in Human Embryonic Kidney 293 Cells

Abstract: We established three human embryonic kidney (HEK) 293 cell lines stably expressing ␣ 1 -adrenoceptor (AR) subtypes, one (␣ 1A

Cited by 29 publications

References 39 publications

Heterodimers of α_1B- and α_1D-Adrenergic Receptors Form a Single Functional Entity

Heterodimers of α_1B- and α_1D-Adrenergic Receptors Form a Single Functional Entity

Heterodimerization of serotonin receptors 5-HT1A and 5-HT7 differentially regulates receptor signalling and trafficking

Blockade of both α_1A- and α_1B-adrenergic receptor subtype signaling is required to inhibit neointimal formation in the mouse femoral artery

Contact Info

Product

Resources

About

Pharmacological Characterization and Cross Talk of α1A- and α1B-Adrenoceptors Coexpressed in Human Embryonic Kidney 293 Cells

Abstract: We established three human embryonic kidney (HEK) 293 cell lines stably expressing ␣ 1 -adrenoceptor (AR) subtypes, one (␣ 1A

Cited by 29 publications

References 39 publications

Heterodimers of α1B- and α1D-Adrenergic Receptors Form a Single Functional Entity

Heterodimers of α1B- and α1D-Adrenergic Receptors Form a Single Functional Entity

Heterodimerization of serotonin receptors 5-HT1A and 5-HT7 differentially regulates receptor signalling and trafficking

Blockade of both α1A- and α1B-adrenergic receptor subtype signaling is required to inhibit neointimal formation in the mouse femoral artery

Contact Info

Product

Resources

About

Pharmacological Characterization and Cross Talk of α_1A- and α_1B-Adrenoceptors Coexpressed in Human Embryonic Kidney 293 Cells

Heterodimers of α_1B- and α_1D-Adrenergic Receptors Form a Single Functional Entity

Heterodimers of α_1B- and α_1D-Adrenergic Receptors Form a Single Functional Entity

Blockade of both α_1A- and α_1B-adrenergic receptor subtype signaling is required to inhibit neointimal formation in the mouse femoral artery