ADRA2B
Description
The ADRA2B (adrenoceptor alpha 2B) is a protein-coding gene located on chromosome 2.
The alpha-2B adrenergic receptor (α2B adrenoceptor) is a G-protein coupled receptor and a subtype of the adrenergic receptor family. The human gene encoding this receptor is called ADRA2B. Orthologs of ADRA2B have been identified in several mammals. There are three highly homologous subtypes of α2-adrenergic receptors: α2A, α2B, and α2C. These receptors play a critical role in regulating neurotransmitter release from sympathetic nerves and adrenergic neurons in the central nervous system. The ADRA2B gene encodes the α2B subtype, which interacts with eIF-2B, a guanine nucleotide exchange protein involved in translation regulation. A polymorphic variant of the α2B subtype, lacking 3 glutamic acids from a glutamic acid repeat element, exhibits decreased G protein-coupled receptor kinase-mediated phosphorylation and desensitization. This variant is also associated with reduced basal metabolic rate in obese individuals, potentially contributing to the pathogenesis of obesity. The ADRA2B gene lacks introns in both its coding and untranslated sequences. A deletion variant of the α2B adrenergic receptor has been linked to emotional memory in Europeans and Africans. This variant predisposes individuals to focus more on negative aspects of a situation. This predisposition persists in people with the variant gene even after taking a single dose of the noradrenergic antidepressant reboxetine, but is weakened in those without the variant.
The alpha-2B adrenergic receptor (ADRA2B) mediates the inhibition of adenylate cyclase through the action of G proteins. This inhibition is triggered by catecholamines, with the following rank order of potency for agonists: clonidine > norepinephrine > epinephrine = oxymetazoline > dopamine > p-tyramine = phenylephrine > serotonin > p-synephrine/p-octopamine. The rank order of potency for antagonists is yohimbine > chlorpromazine > phentolamine > mianserine > spiperone > prazosin > alprenolol > propanolol > pindolol.
ADRA2B is also known as ADRA2L1, ADRA2RL1, ADRARL1, ALPHA2BAR, FAME2, alpha-2BAR.
