Additional info: |
Leukotriene B4 (LTB4) promotes a number of leukocyte functions including aggregation, stimulation of ion fluxes, superoxide anion production, chemotaxis, and chemokinesis. Two G-protein coupled receptors, BLT1 and BLT2, which mediate the actions of LTB4 have been cloned and characterized. The BLT1 receptor is expressed in leukocytes, U937 cells, and to a much lower extent in spleen and thymus. The human BLT2 receptor is a 358 amino acid protein with approximately 40% homology to BLT1 at the amino acid level. The BLT2 receptor is more broadly expressed than the BLT1 receptor, with highest levels observed in liver, spleen, ovary, intestine, and peripheral blood leukocytes. Activation of the BLT2 receptor by LTB4 leads to Ca2+ mobilization as well as decreases in cyclic AMP, indicating interaction of the receptor with Gq and Gi classes of G-proteins. |