GPCR Research Reagents

G protein-coupled receptors (GPCR) are so named because of their regulation of an intracellular heterotrimeric complex made up of Ga, and Gbg subunits. Ligand binding to receptor stimulates the well-described exchange of GDP for GTP by Ga. This activity lies at the apex of numerous signaling cascades induced by a range of different stimuli including light, odorants, amino acids, nucleotides, lipids, and peptides/proteins. GPCRs make up the largest family of integral membrane proteins and account for approximately 5% of all genes found in the human genome.1 Clinically, approximately 45% of modern drugs target GPCRs, underscoring the importance of having quality research tools to study their functions.2 R&D Systems continues to expand its selection of products for GPCR research to include reagents for at least 20 chemokine receptors, as well as other GPCRs in key areas of biological Science (Table 1).

Table 1. G Protein-related Products
GPCR Antibodies Proteins Primers mRNA Quantitation Kits
APJ H      
CD97 H H    
D6 H      
ChemR23 H      
Chemokine Receptors
(CCR,CXCR,CX3,CR,XCR)a		 H,M   H,M,R H
EDG-1 H      
FPRL1/LXA4R H      
Frizzled-1 through 9b H,M H,M    
GABA-B-R2 H      
HCR/CRAM-A/B H      
HM74A/GPR109A H      
Leukotriene B4R1 H      
Key: H-Human, M-Mouse, R-Rat
a. See our complete listing of chemokine receptor products.
b. See our complete listing of frizzled receptor products.

One example, FPRL1/LXA4R, is a GPCR with homology to the formyl peptide receptor (FPR1) and is activated by formyl-methionyl-leucyl-phenylalanine (fMLP). However, FPRL1/LXA4R binds fMLP with only low affinity (Kd ~5 µM). 3 In contrast, lipoxin A4 (LXA4), a bioactive eicosanoid, has been identified to be the most potent endogenous ligand of FPRL1/LXA4R with a Kd about 3 orders of magnitude higher than that of fMLP. FPRL1/LXA4R mediates the anti-inflammatory effects of LXA4, and stable LXA4 analogs, to modulate leukocyte trafficking and promote the resolution of inflammation.4,5 The receptor is also thought to mediate the actions of pro-inflammatory mediators associated with human diseases, including amyloidosis, Alzheimer’s disease, prion disease, and HIV. 6
R&D Systems now offers a monoclonal antibody specific for the G protein-coupled receptor FPRL1/LXA4R (Catalog # MAB3479; Figure 1).

References

  1. Takeda, S. et al. (2002) FEBS Lett. 520:97.
  2. Drews, J. (2000) Science 287:1960.
  3. Fiore, S. & C.N. Serhan (1995) Biochemistry 34:16678.
  4. Fiore, S. et al. (1994) J. Exp. Med. 180:253.
  5. Takano, T. et al. (1997) J. Exp. Med. 185:1693.
  6. Le, Y. et al. (2002) Trends Immunol. 23:541.