LTB4R2

Description

The LTB4R2 (leukotriene B4 receptor 2) is a protein-coding gene located on chromosome 14.

Leukotriene B4 receptor 2, also known as BLT2, BLT2 receptor, and BLTR2, is an Integral membrane protein that is encoded by the LTB4R2 gene in humans and the Ltbr2 gene in mice. Discovered several years after the leukotriene B4 receptor 1 (BLT1), BLT2 receptor binds leukotriene B4 (LTB4) with far lower affinity than the BLT1 receptor does and therefore has been termed the low affinity LTB4 receptor. Sometime after its initial discovery, the BLT2 receptor was shown to bind and become activated by several other arachidonic acid metabolites, one of which, 12-hydroxyheptadecatrienoic acid (12-HHT), has 10- to 100-fold higher affinity for it than does LTB4; 12-HHT fails to bind or activate BLT1 receptors. While BLT2 receptors have some actions similar to BLT1 receptors, they have other actions which clearly oppose those of BLT1 in regulating inflammation and allergic responses; BLT2 receptors also have actions that extend beyond those of BLT1 receptors. Laboratory, animal, and other pre-clinical studies suggest that BLT2 receptors may be involved not only in inflammation and allergy but also in human cancer.

== Function == BLT2 is a Cell surface receptor that functions by recognizing, binding, and mediating responses to a particular set of messenger molecules or ligands. These messenger ligands are any one of a range of structurally different arachidonic acid metabolites made and released by nearby cells to act as paracrine signals for coordinating responses between cells or autocrine signals for modulating their parent cells' responses.

== Genes == Several years after their identification of a Leukotriene B4 (LTB4) receptor termed BLT1 or BLTR1 and encoded by the LTB4R1 gene, Shimizu and colleagues identified a second LTB4 receptor, BLT2 or BLTR2, encoded by the LTB4R2 gene. LTBR1 and LTBR2 encode for proteins with 45% amino acid identity that belong to the G protein–coupled receptor superfamily. The two genes form a cluster on human and mouse chromosome 14; in humans but not mice, this cluster has a very unusual configuration in that LTBR2's open reading frame overlaps the Promoter (genetics) and 5' Untranslated region of LTBR1.

LTB4R2 is a low-affinity receptor for leukotrienes, including leukotriene B4. It mediates chemotaxis of granulocytes and macrophages, a process where these immune cells move towards a chemical signal. This response is triggered through G-proteins, which activate a signaling pathway involving phosphatidylinositol and calcium. LTB4R2 binds to leukotrienes in the following order of affinity: LTB4 > 12-epi-LTB4 > LTB5 > LTB3.

LTB4R2 is also known as BLT2, BLTR2, JULF2, KPG_004, LTB4-R 2, LTB4-R2, NOP9.

Associated Diseases

WES Whole Exome Sequencing