Bradykinin receptor B2

Bradykinin receptor B2, also known as BDKRB2, is a bradykinin receptor, but also denotes the human gene encoding it.

Mechanism
The B2 receptor is a G protein-coupled receptor, probably coupled to Gq and Gi. Gq stimulates phospholipase C to increase intracellular free calcium and Gi 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 (A1-7) also potentiates bradykinin action on B2 receptors.

Kallidin also signals through the B2 receptor.

Function
The 9 amino acid bradykinin peptide elicits many responses including vasodilation, edema, smooth muscle spasm and pain fiber stimulation.

Gene
Alternate start codons result in two isoforms of the protein.