Bradykinin receptor B
2 is a
G-protein coupled receptor
G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large group of evolutionarily-related p ...
for
bradykinin
Bradykinin (BK) (Greek brady-, slow; -kinin, kīn(eîn) to move) is a peptide that promotes inflammation. It causes arterioles to dilate (enlarge) via the release of prostacyclin, nitric oxide, and endothelium-derived hyperpolarizing factor and ...
, encoded by the BDKRB2
gene
In biology, the word gene (from , ; "... Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a b ...
in humans.
Mechanism
The B
2 receptor is a
G protein-coupled receptor
G protein-coupled receptors (GPCRs), also known as seven-(pass)-transmembrane domain receptors, 7TM receptors, heptahelical receptors, serpentine receptors, and G protein-linked receptors (GPLR), form a large group of evolutionarily-related p ...
, probably coupled to
Gq and
Gi. G
q stimulates
phospholipase C to increase
intracellular
This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions ...
free
calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...
and G
i inhibits
adenylate cyclase
Adenylate cyclase (EC 4.6.1.1, also commonly known as adenyl cyclase and adenylyl cyclase, abbreviated AC) is an enzyme with systematic name ATP diphosphate-lyase (cyclizing; 3′,5′-cyclic-AMP-forming). It catalyzes the following reaction:
:A ...
. Furthermore, the receptor stimulates the
mitogen-activated protein kinase pathways. It is ubiquitously and constitutively expressed in healthy tissues.
The B
2 receptor forms a complex with angiotensin converting enzyme (ACE), and this is thought to play a role in cross-talk between the renin-angiotensin system (RAS) and the
kinin–kallikrein system
The kinin–kallikrein system or simply kinin system is a poorly understood hormonal system with limited available research. It consists of blood proteins that play a role in inflammation, blood pressure control, coagulation and pain. Its import ...
(KKS). The heptapeptide
angiotensin (1-7)
Angiotensin (1-7) (; Molecular weight = 899.02 g/mol; H- Asp- Arg-Val- Tyr- Ile-His- Pro-OH) is an active heptapeptide of the renin–angiotensin system (RAS).
In 1988, Santos ''et al'' demonstrated that angiotensin (1-7) was a main product of th ...
also potentiates bradykinin action on B
2 receptors.
Kallidin
Kallidin is a bioactive kinin formed in response to injury from kininogen precursors through the action of kallikreins.
Kallidin is a decapeptide whose sequence is H-Lys-Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg-OH. It can be converted to bradykinin b ...
also signals through the B
2 receptor. An antagonist for the receptor is Hoe 140 (
icatibant
Icatibant, sold under the brand name Firazyr, is a medication for the symptomatic treatment of acute attacks of hereditary angioedema (HAE) in adults with C1-esterase-inhibitor deficiency. It is not effective in angioedema caused by medication f ...
).
Function
The 9
amino acid
Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha a ...
bradykinin
peptide
Peptides (, ) are short chains of amino acids linked by peptide bonds. Long chains of amino acids are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides.
...
elicits several responses including
vasodilation
Vasodilation is the widening of blood vessels. It results from relaxation of smooth muscle cells within the vessel walls, in particular in the large veins, large arteries, and smaller arterioles. The process is the opposite of vasoconstrictio ...
,
edema,
smooth muscle spasm and
nociceptor
A nociceptor ("pain receptor" from Latin ''nocere'' 'to harm or hurt') is a sensory neuron that responds to damaging or potentially damaging stimuli by sending "possible threat" signals to the spinal cord and the brain. The brain creates the sens ...
stimulation.
Gene
Alternate start codons result in two isoforms of the protein.
See also
*
Bradykinin receptor
The bradykinin receptor family is a group of G-protein coupled receptors whose principal ligand is the protein bradykinin.
There are two Bradykinin receptors: the B1 receptor and the B2 receptor.
B1 receptor
Bradykinin receptor B1 (B1) is a ...
References
Further reading
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External links
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G protein-coupled receptors
{{transmembranereceptor-stub