Alpha-2B adrenergic receptor
Encyclopedia
The alpha-2B adrenergic receptor (α2B adrenoceptor), is a G-protein coupled receptor. It is a subtype of the adrenergic receptor
family. The human gene
encoding this receptor has the symbol ADRA2B.
ADRA2B orthologs have been identified in several mammals.
release from sympathetic nerves and from adrenergic neurons in the central nervous system
.
s from a glutamic acid repeat element, was identified to have decreased G protein-coupled receptor
kinase
-mediated phosphorylation and desensitization
; this polymorphic form is also associated with reduced basal metabolic rate
in obese subjects and may therefore contribute to the pathogenesis of obesity. This gene contains no introns in either its coding
or untranslated sequences.
A deletion variant of the alpha-2B adrenergic receptor has been shown to be related to emotional memory in Europeans and Africans.
phylogenetic marker. This intronless gene has first been used to explore the phylogeny of the major groups of mammals, and contributed to reveal that placental orders are distributed into four major clades: Xenarthra
, Afrotheria
, Laurasiatheria
, and Euarchonta
plus Glires
. Comparative analysis of the primary protein sequence of ADRA2B across placentals also showed the high conservation of residues thought to be involved in agonist binding and in G protein–coupling. However, great variations are observed in the very long, third intracellular loop, with a polyglutamyl domain displaying pervasive length differences in length.
Adrenergic receptor
The adrenergic receptors are a class of metabotropic G protein-coupled receptors that are targets of the catecholamines, especially noradrenaline and adrenaline ....
family. The human gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
encoding this receptor has the symbol ADRA2B.
ADRA2B orthologs have been identified in several mammals.
Receptor
Alpha-2-adrenergic receptors include 3 highly homologous subtypes: alpha2A, alpha2B, and alpha2C. These receptors have a critical role in regulating neurotransmitterNeurotransmitter
Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to...
release from sympathetic nerves and from adrenergic neurons in the central nervous system
Central nervous system
The central nervous system is the part of the nervous system that integrates the information that it receives from, and coordinates the activity of, all parts of the bodies of bilaterian animals—that is, all multicellular animals except sponges and radially symmetric animals such as jellyfish...
.
Gene
This gene encodes the alpha2B subtype, which was observed to associate with eIF-2B, a guanine nucleotide exchange protein that functions in regulation of translation. A polymorphic variant of the alpha2B subtype, which lacks 3 glutamic acidGlutamic acid
Glutamic acid is one of the 20 proteinogenic amino acids, and its codons are GAA and GAG. It is a non-essential amino acid. The carboxylate anions and salts of glutamic acid are known as glutamates...
s from a glutamic acid repeat element, was identified to have decreased G protein-coupled receptor
G protein-coupled receptor
G protein-coupled receptors , also known as seven-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptor, and G protein-linked receptors , comprise a large protein family of transmembrane receptors that sense molecules outside the cell and activate inside signal...
kinase
Kinase
In chemistry and biochemistry, a kinase is a type of enzyme that transfers phosphate groups from high-energy donor molecules, such as ATP, to specific substrates, a process referred to as phosphorylation. Kinases are part of the larger family of phosphotransferases...
-mediated phosphorylation and desensitization
Desensitization
Desensitization can refer to:* Desensitization * Desensitization * Desensitization * Desensitization of explosives, see Phlegmatized...
; this polymorphic form is also associated with reduced basal metabolic rate
Basal metabolic rate
Basal Metabolic Rate , and the closely related resting metabolic rate , is the amount of daily energy expended by humans and other animals at rest. Rest is defined as existing in a neutrally temperate environment while in the post-absorptive state...
in obese subjects and may therefore contribute to the pathogenesis of obesity. This gene contains no introns in either its coding
Coding region
The coding region of a gene, also known as the coding sequence or CDS, is that portion of a gene's DNA or RNA, composed of exons, that codes for protein. The region is bounded nearer the 5' end by a start codon and nearer the 3' end with a stop codon...
or untranslated sequences.
A deletion variant of the alpha-2B adrenergic receptor has been shown to be related to emotional memory in Europeans and Africans.
Evolution
The ADRA2B gene (sometimes referenced as A2AB) is used in animals as a nuclear DNANuclear DNA
Nuclear DNA, nuclear deoxyribonucleic acid , is DNA contained within a nucleus of eukaryotic organisms. In mammals and vertebrates, nuclear DNA encodes more of the genome than the mitochondrial DNA and is composed of information inherited from two parents, one male, and one female, rather than...
phylogenetic marker. This intronless gene has first been used to explore the phylogeny of the major groups of mammals, and contributed to reveal that placental orders are distributed into four major clades: Xenarthra
Xenarthra
The superorder Xenarthra is a group of placental mammals , existent today only in the Americas and represented by anteaters, tree sloths, and armadillos. The origins of the order can be traced back as far as the Paleogene in South America...
, Afrotheria
Afrotheria
Afrotheria is a clade of mammals, the living members of which belong to groups from Africa or of African origin: golden moles, sengis , tenrecs, aardvarks, hyraxes, elephants and sea cows. The common ancestry of these animals was not recognized until the late 1990s...
, Laurasiatheria
Laurasiatheria
Laurasiatheria is a large group of placental mammals believed to have originated on the northern supercontinent of Laurasia. It includes shrews, hedgehogs, pangolins, bats, whales, most hoofed mammals, and carnivorans, among others....
, and Euarchonta
Euarchonta
The Euarchonta are a grandorder of mammals containing four orders: the Dermoptera or colugos, the Scandentia or treeshrews, the extinct Plesiadapiformes, and the Primates....
plus Glires
Glires
Glires is a clade consisting of rodents and lagomorphs . This hypothesis that these form a monophyletic group has been long debated based on morphological evidence, although recent morphological studies strongly support monophyly of Glires...
. Comparative analysis of the primary protein sequence of ADRA2B across placentals also showed the high conservation of residues thought to be involved in agonist binding and in G protein–coupling. However, great variations are observed in the very long, third intracellular loop, with a polyglutamyl domain displaying pervasive length differences in length.