Affinage

ADRA2B

Alpha-2B adrenergic receptor · UniProt P18089

Length
450 aa
Mass
50.0 kDa
Annotated
2026-06-09
20 papers in source corpus 4 papers cited in narrative 4 extracted findings
Cross-family judge vs UniProt: tie faithfulness: 3/3 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

ADRA2B encodes the α2B-adrenergic receptor, a biogenic amine G-protein-coupled receptor that mediates norepinephrine signaling (PMID:37525034). A common 9-nucleotide coding deletion (+901 Del, del 301–303) markedly reduces receptor desensitization in vitro, yet does not alter in vivo vascular sensitivity (ED50) to the selective α2-adrenergic agonist dexmedetomidine in human dorsal hand vein assays (PMID:15900214). This coding variant is in complete linkage disequilibrium with a promoter insertion at position -4825 that reduces ADRA2B transcriptional activity and alters the pattern of nuclear protein binding to the promoter region (PMID:19728989). Beyond these polymorphism-focused functional studies, the receptor's downstream signaling mechanism and effector coupling have not been characterized in the available corpus.

Mechanistic history

Synthesis pass · year-by-year structured walk · 4 steps
  1. 2005 Medium

    Established whether the desensitization-reducing +901 Del coding variant translates into altered vascular pharmacodynamics in humans, distinguishing in vitro receptor behavior from in vivo drug response.

    Evidence In vivo dorsal hand vein venoconstriction dose-response to dexmedetomidine with genetic haplotyping

    PMID:15900214

    Open questions at the time
    • Decreased desensitization was cited from prior work, not directly re-demonstrated
    • No mechanistic link between the genotype and the reduced Emax haplotype was established
    • Effector coupling and signaling consequences of altered desensitization not measured
  2. 2009 Medium

    Identified a linked regulatory promoter polymorphism, showing ADRA2B variation can act at the transcriptional level in addition to the coding level.

    Evidence Luciferase reporter transfection assays and EMSA with the 5.5 kb ADRA2B promoter in multiple cell lines

    PMID:19728989

    Open questions at the time
    • Single lab, no in vivo validation of reduced transcription
    • Identity of the differentially bound transcription factors not determined
    • Combined functional effect of the linked promoter+coding haplotype not resolved
  3. 2022 Low

    Tested whether ADRA2B antagonism is a molecular initiating event for environmental toxicant effects, extending the receptor's relevance beyond endogenous adrenergic signaling.

    Evidence In silico target prediction with pharmacological yohimbine antagonism in zebrafish larvae, scored by heart rate and behavioral phenotypes

    PMID:35248961

    Open questions at the time
    • Pharmacological phenocopy only; no direct carbaryl-receptor binding assay or mutagenesis
    • Single study in zebrafish, human relevance unestablished
    • Yohimbine is not selective for ADRA2B
  4. 2023 Low

    Placed ADRA2B within the biogenic amine GPCR sub-cluster and flagged conserved signaling motifs, providing a structural-evolutionary frame for its receptor activity.

    Evidence Computational evolutionary and structural comparison of GPCR family members

    PMID:37525034

    Open questions at the time
    • Purely computational, no experimental functional validation
    • Conserved motifs not tested by mutagenesis in ADRA2B
    • Does not define ligand binding or G-protein coupling experimentally

Open questions

Synthesis pass · forward-looking unresolved questions
  • The downstream signaling pathway, effector coupling, and physiological role of the α2B-adrenergic receptor remain undefined in this corpus.
  • No direct measurement of G-protein coupling or second-messenger output
  • No structural model of ligand binding from experimental data
  • Functional consequence of the linked promoter+coding haplotype on receptor signaling unresolved

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
No controlled-vocabulary terms were assigned to this entry.

Evidence

Reading pass · 4 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2009 A novel 12-nucleotide insertion polymorphism at position -4825 in the ADRA2B promoter is in complete linkage disequilibrium with the +901 Del (9-nucleotide deletion) coding-region polymorphism. The -4825 insertion reduces ADRA2B transcriptional activity in cell transfection assays, and EMSA demonstrated that this region binds nuclear proteins with an altered pattern of transcription factor binding for the insertion allele compared to deletion allele. Luciferase reporter transfection assays with 5.5 kb ADRA2B promoter constructs in multiple cell lines; electrophoretic mobility shift assay (EMSA) with nuclear protein extracts Biochemical pharmacology Medium 19728989
2005 The +901 Del (9-nucleotide deletion, del 301–303) variant of ADRA2B results in markedly decreased receptor desensitization in vitro, but does not alter vascular sensitivity (ED50) to the selective α2-adrenergic agonist dexmedetomidine in vivo; a promoter/3'-UTR haplotype found in African-Americans was associated with reduced maximal venoconstriction (Emax). In vitro receptor desensitization assay (cited from prior work); in vivo dorsal hand vein venoconstriction dose-response with dexmedetomidine measured by linear variable differential transformer; haplotype inference by EM algorithm Pharmacogenetics and genomics Medium 15900214
2022 In zebrafish larvae, ADRA2B (α2B adrenoceptor) was identified as a molecular target of the insecticide carbaryl; pharmacological antagonism of ADRA2B (using yohimbine as a prototypic antagonist) mimicked carbaryl-induced increases in heart rate and behavioural impairments, suggesting antagonism of ADRA2B as the molecular initiating event for carbaryl's adverse effects. In silico target prediction followed by in vitro validation; pharmacological antagonism with yohimbine in zebrafish larvae; heart rate and behavioral phenotype assays Journal of hazardous materials Low 35248961
2023 Evolutionary and structural analysis of ADRA2B identified conserved motifs shared among biogenic amine receptor GPCRs that are proposed to play key roles in GPCR family signaling; structural comparison placed ADRA2B within the biogenic amine receptor sub-cluster. Computational evolutionary analysis and structural comparison of GPCR family members Advances in experimental medicine and biology Low 37525034

Source papers

Stage 0 corpus · 20 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2005 Variation in the alpha2B-adrenergic receptor gene (ADRA2B) and its relationship to vascular response in vivo. Pharmacogenetics and genomics 31 15900214
2013 ADRA2B genotype modulates effects of acute psychosocial stress on emotional memory retrieval in healthy young men. Neurobiology of learning and memory 30 23583499
2007 Physical activity, diet, and incident diabetes in relation to an ADRA2B polymorphism. Medicine and science in sports and exercise 26 17277585
2013 Deletion variant in the ADRA2B gene increases coupling between emotional responses at encoding and later retrieval of emotional memories. Neurobiology of learning and memory 22 24149058
2022 Environmental levels of carbaryl impair zebrafish larvae behaviour: The potential role of ADRA2B and HTR2B. Journal of hazardous materials 21 35248961
2018 ADRA2B deletion variant and enhanced cognitive processing of emotional information: A meta-analytical review. Neuroscience and biobehavioral reviews 16 29751052
2016 The modulating role of ADRA2B in emotional working memory: Attending the negative but remembering the positive. Neurobiology of learning and memory 15 26899992
2010 Lifestyle modifies the relationship between body composition and adrenergic receptor genetic polymorphisms, ADRB2, ADRB3 and ADRA2B: a secondary analysis of a randomized controlled trial of physical activity among postmenopausal women. Behavior genetics 15 20401689
2014 ADRA2B genotype differentially modulates stress-induced neural activity in the amygdala and hippocampus during emotional memory retrieval. Psychopharmacology 14 25127926
2005 Cardiovascular and metabolic phenotypes in relation to the ADRA2B insertion/deletion polymorphism in a Chinese population. Journal of hypertension 13 16269962
2017 ADRA2B deletion variant influences time-dependent effects of pre-learning stress on long-term memory. Neurobiology of learning and memory 11 28254464
2011 Influence of COMT val158met and ADRA2B deletion polymorphisms on recollection and familiarity components of human emotional memory. Journal of psychopharmacology (Oxford, England) 11 21965191
2009 Chromosome 2q12, the ADRA2B I/D polymorphism and metabolic syndrome. Journal of hypertension 7 19593211
2009 Identification of a novel 12-nucleotide insertion polymorphism in the promoter region of ADRA2B: full linkage with the 9-nucleotide deletion in the coding region and influence on transcriptional activity. Biochemical pharmacology 7 19728989
2023 ADRA2B and HTR1A: An Updated Study of the Biogenic Amine Receptors Reveals Novel Conserved Motifs Which Play Key Role in Mental Disorders. Advances in experimental medicine and biology 4 37525034
2005 ADRA2B gene insertion/deletion polymorphism and artery compliance. Chinese medical journal 4 16336817
2017 The ADRA2B gene in the production of false memories for affective information in healthy female volunteers. Behavioural brain research 3 28697904
2014 A 9-nucleotide Ins/Del in ADRA2B modulates orientation of attention to facial expressions and emotional words. Behavioural pharmacology 3 25325286
2010 Lack of association between ADRA2B-4825 gene insertion/deletion polymorphism and migraine in Chinese Han population. Neuroscience bulletin 3 20651814
2024 Identification of a de novo CACNA1B variant and a start-loss ADRA2B variant in paroxysmal kinesigenic dyskinesia. Heliyon 1 38571653

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