BDKRB2
Identifiers
Aliases	BDKRB2, B2R, BK-2, BK2, BKR2, BRB2, bradykinin receptor B2
External IDs	OMIM: 113503 MGI: 102845 HomoloGene: 519 GeneCards: BDKRB2
Gene location (Human) Chr. Chromosome 14 (human)[1] Band 14q32.2 Start 96,204,679 bp[1] End 96,244,166 bp[1]
Gene location (Mouse) Chr. Chromosome 12 (mouse)[2] Band 12 E|12 55.76 cM Start 105,529,485 bp[2] End 105,561,496 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in stromal cell of endometrium mucosa of urinary bladder pancreatic ductal cell gums gallbladder canal of the cervix epithelium of esophagus cavity of mouth vagina vulva Top expressed in esophagus adrenal gland pituitary gland lip duodenum placenta ileum stomach colon cerebellar cortex More reference expression data BioGPS More reference expression data
Gene ontology Molecular function G protein-coupled receptor activity type 1 angiotensin receptor binding signal transducer activity protease binding protein binding protein heterodimerization activity phosphatidylinositol phospholipase C activity bradykinin receptor activity Cellular component integral component of membrane endosome membrane integral component of plasma membrane plasma membrane Biological process G protein-coupled receptor signaling pathway negative regulation of intrinsic apoptotic signaling pathway in response to osmotic stress response to salt stress vasoconstriction transmembrane receptor protein tyrosine kinase signaling pathway response to stress negative regulation of intrinsic apoptotic signaling pathway in response to osmotic stress by p53 class mediator vasodilation blood circulation cell surface receptor signaling pathway regulation of vascular permeability regulation of vasoconstriction negative regulation of peptidyl-serine phosphorylation inflammatory response arachidonic acid secretion signal transduction smooth muscle contraction positive regulation of cytosolic calcium ion concentration Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 624 12062 Ensembl ENSG00000168398 ENSMUSG00000021070 UniProt P30411 P32299 RefSeq (mRNA) NM_000623 NM_001379692 NM_009747 RefSeq (protein) NP_000614 NP_001366621 NP_033877 Location (UCSC) Chr 14: 96.2 – 96.24 Mb Chr 12: 105.53 – 105.56 Mb PubMed search [3] [4]
Wikidata
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Bradykinin receptor B₂ is a G-protein coupled receptor for bradykinin, encoded by the BDKRB2 gene in humans.

Mechanism

The B₂ receptor (B₂R) is a G protein-coupled receptor, probably coupled to G_q and G_i. A 2022 Nature cryo-EM study of human B₂R-G_q complexes by Jinkeng Sheng et al. investigated the proximal activation mechanisms of B₂R. Sheng et al. propose that upon B₂R binding bradykinin or kallidin to a "bulky orthosteric binding pocket," the phenylalanine F8 or F9 residue of bradykinin or kallidin respectively interacts with a "conserved toggle switch" W283. This hydrophobic interaction facilitates the outward movement of transmembrane domain 6 (TM6) of B₂R on the cytoplasmic side of the membrane, as well as outward movement of F279, a key residue within the conserved PIF motif of GPCRs (involving proline, isoleucine and phenylalanine). This rearrangement of the PIF motif disrupts the ionic lock formed by the DRY motif and pushes the NPxxY motif towards the activated state, opening an "intracellular cleft" for insertion of the α5-helix of G_q. ^[5]

G_q stimulates phospholipase C to increase intracellular free calcium and G_i inhibits adenylate cyclase. Furthermore, the receptor stimulates the mitogen-activated protein kinase pathways. It is ubiquitously and constitutively expressed in healthy tissues.

The B₂ 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 (KKS). The heptapeptide angiotensin (1-7) also potentiates bradykinin action on B₂ receptors.^[6]

Kallidin also signals through the B₂ receptor. An antagonist for the receptor is Hoe 140 (icatibant).^[7]

Function

The 9 amino acid bradykinin peptide elicits several responses including vasodilation, edema, smooth muscle spasm and nociceptor stimulation.

Gene

Alternate start codons result in two isoforms of the protein.^[8]