Identification and profiling of novel α 1A-adrenoceptor-CXC chemokine receptor 2 heteromer

Sanam Mustafa, Heng B. See, Ruth M. Seeber, Stephen P. Armstrong, Carl W. White, Sabatino Ventura, Mohammed Akli Ayoub, Kevin D.G. Pfleger

Research output: Contribution to journalArticlepeer-review

50 Scopus citations


We have provided the first evidence for specific heteromerization between the α 1A-adrenoceptor (α 1AAR) and CXC chemokine receptor 2 (CXCR2) in live cells. α 1AAR and CXCR2 are both expressed in areas such as the stromal smooth muscle layer of the prostate. By utilizing the Gprotein-coupled receptor (GPCR) heteromer identification technology on the live cellbased bioluminescence resonance energy transfer (BRET) assay platform, our studies in human embryonic kidney 293 cells have identified norepinephrine-dependent β-arrestin recruitment that was in turn dependent upon co-expression of α 1AAR with CXCR2. These findings have been supported by co-localization observed using confocal microscopy. This norepinephrine-dependent β-arrestin recruitment was inhibited not only by the α 1AR antagonist Terazosin but also by the CXCR2-specific allosteric inverse agonist SB265610. Furthermore, Labetalol, which is marketed for hypertension as a nonselective β-adrenoceptor antagonist with α 1AR antagonist properties, was identified as a heteromer-specific-biased agonist exhibiting partial agonism for inositol phosphate production but essentially full agonism for β-arrestin recruitment at the α 1AAR-CXCR2 heteromer. Finally, bioluminescence resonance energy transfer studies with both receptors tagged suggest that α 1AAR-CXCR2 heteromerization occurs constitutively and is not modulated by ligand. These findings support the concept of GPCR heteromer complexes exhibiting distinct pharmacology, thereby providing additional mechanisms through which GPCRs can potentially achieve their diverse biological functions. This has important implications for the use and future development of pharmaceuticals targeting these receptors.

Original languageBritish English
Pages (from-to)12952-12965
Number of pages14
JournalJournal of Biological Chemistry
Issue number16
StatePublished - 13 Apr 2012


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