Description
General description
: Full-length human CXCR1 cDNA
CXCR1 (also known as IL-8RA) is a Gi/o-coupled GPCR expressed on neutrophils, CD8(+) T cells, and intestinal epithelial cells (Murphy, 1997; Sturm et al., 2005; Takata et al., 2004). CXCR1 binds specifically to the chemokine interleukin-8 (IL-8), whereas a related receptor, CXCR2, binds promiscuously to IL-8 and several other chemokines. CXCR1 has been proposed to be the primary regulator of neutrophil response to IL-8 in sepsis (Cummings et al., 1999). Antagonists of CXCR1 and CXCR2 have been developed and display efficacy in animal models of reperfusion injury (Bertini, et al., 2004; Kaneider et al., 2005). Millipore′s CXCR1 membrane preparations are crude membrane preparations made from our proprietary stable recombinant cell lines to ensure high-level of GPCR surface expression; thus, they are ideal HTS tools for screening of antagonists of CXCR1 interaction with IL-8. The membrane preparations exhibit a Kd of 0.2 nM for [125I]-IL-8. With 5 μg/well CXCR1 Membrane Prep and 0.1 nM [125I]-IL-8, a greater than 5-fold signal-to-background ratio is obtained.
Application
Radioligand binding assay, and GTPgammaS binding.
Biochem/physiol Actions
GPCR Class: A
Protein Target: CXCR1 / IL-8a
Target Sub-Family: Chemokine
Features and Benefits
Inucbation Conditions
RECOMMENDED ASSAY CONDITIONS: Membranes are mixed with radioactive ligand and unlabeled competitor (see Figures 1 and 2 for concentrations tested) in binding buffer in a nonbinding 96-well plate, and incubated for 1-2 h. Prior to filtration, an FC 96-well harvest plate (Millipore cat. # MAHF C1H) is coated with 0.33% polyethyleneimine for 30 min, then washed with 50mM HEPES, pH 7.4, 0.5% BSA. Binding reaction is transferred to the filter plate, and washed 3 times (1 mL per well per wash) with Wash Buffer. The plate is dried and counted.
Binding buffer: 50 mM Hepes, pH 7.4, 5 mM MgCl2, 1 mM CaCl2, 0.2% BSA, filtered and stored at 4°C
Radioligand: [125I] Interleukin-8 (Perkin Elmer #NEX277)
Wash Buffer: 50 mM Hepes, pH 7.4, 500mM NaCl , 0.1% BSA, filtered and stored at 4°C.
One vial contains enough membranes for at least 200 assays (units), where an unit is the amount of membrane that will yield greater than 5-fold signal:background with 125I-labeled IL-8 at 0.1 nM
Physical form
Liquid in packaging buffer: 50 mM Tris pH 7.4, 10% glycerol and 1% BSA no preservatives.Packaging method: Membranes protein were adjusted to the indicated concentration in packaging buffer, rapidly frozen, and stored at -80°C.
Preparation Note
Maintain frozen at -70°C for up to 2 years. Do not freeze and thaw.
Analysis Note
Table 1. Signal:background and specific binding values obtained in a competition binding assay with varying amounts of CXCR1 Receptor membrane preparation in a dose response curve with unlabeled IL-8.
5 µg/well 10 µg/well
Signal:Background 14.8 12.8
Specific Binding (cpm) 8965 9624
SPECIFICATIONS: 1 unit = 5 μg
Bmax: 3.7 pmol/mg;
Kd: 0.2 nM
Legal Information
CHEMICON is a registered trademark of Merck KGaA, Darmstadt, Germany
Disclaimer
Unless otherwise stated in our catalog or other company documentation accompanying the product(s), our products are intended for research use only and are not to be used for any other purpose, which includes but is not limited to, unauthorized commercial uses, in vitro diagnostic uses, ex vivo or in vivo therapeutic uses or any type of consumption or application to humans or animals.
