Complement component 5a receptor 2 is a protein of the complement system that in humans is encoded by the C5AR2 gene. [5] [6] It is highly expressed in the blood and spleen, [7] predominantly by myeloid cells. [8] [9]
Complement component 5a receptor 2 is a protein of the complement system that in humans is encoded by the C5AR2 gene. [5] [6] It is highly expressed in the blood and spleen, [7] predominantly by myeloid cells. [8] [9]
The anaphylatoxins C3a and C5a are fragments of C3 and C5 generated via proteolytic cleavage by C3 convertases and C5 convertases during the complement cascade. They are pro-inflammatory mediators which bind to the anaphylatoxin receptors, C3aR, C5aR1 and C5aR2. The anaphylatoxin receptors are a family of three proteins which beloing to the G protein-coupled receptor superfamily. C3aR and C5aR1 bind C3a and C5a, respectively, which mediate a broad range of effects in host defense, including chemoattraction, vasodilation and immune cell activation. [10] C5aR2 binds C5a, but lacks GPCR activity, [11] and its function is less well understood.
C5aR2 was initially thought be a decoy receptor, acting as a sink for C5a to negatively regulate C5aR1 function. [11] However, more recent research has uncovered independent roles for C5aR2, including modulation of the innate immune response in myeloid cells, [12] [13] translocation of C5a to drive transendothelial migration of neutrophils, [14] β-arrestin recruitment and modulation of ERK signalling [15] [16] and modulation of lipid metabolism in obesity through C3a-desArg binding. [17] C5aR2 has been implicated in a broad range of inflammatory and infectious diseases. [18] [19]