ChemiSCREEN™ Membrane Preparation Recombinant Human GPR109A Receptor

ChemiSCREEN™ Membrane Preparation Recombinant Human GPR109A Receptor

Chemicon (Millipore)

200 units

Full-length human GPR109A cDNA

Nicotinic acid (niacin), a vitamin of the B complex, is used clinically in high doses to decrease total plasma levels of cholesterol. Interestingly, the total cholesterol levels and low-density lipoprotein (LDL) concentrations decrease, while the high-density lipoprotein (HDL) concentrations increase with nicotinic acid treatment. The cholesterol-lowering effects of nicotinic acid result from inhibition of lipolysis in adipose tissue, which decreases plasma levels of free fatty acid (FFA) (Altschul et al., 1955; Carlson, 1963). In a study of nicotinic acid and myocardial infarction in the Coronary Drug Project (1966-1975), patients receiving 3 g/day nicotinic acid exhibited reduced rates of myocardial infarction (Coronary Drug Project Research Group, 1975). However, an unwanted effect of high doses of nicotinic acid is vasodilatation, occurring mainly in the upper body and face, known as flushing. Recently two receptors for nicotinic acid have been identified as class A G protein-coupled receptors that couple to Gi to inhibit accumulation of cAMP (Offermans, 2006). GPR109A (also known as HM74A in humans and PUMA-G in mice) is a high affinity receptor for nicotinic acid, whereas GPR109B (also known as HM74) is a low affinity receptor for nicotinic acid that is found in humans but not rodents (Wise et al., 2003). GPCR109A is found primarily in adipose tissue and immune cells. Millipore's GPR109A 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 GPR109A interactions with its ligands. The membrane preparations exhibit EC50s of 3.65 μM for nicotinic acid in a GTPγS binding assay.

Radioligand binding assay and GTPγS binding.

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.

FUNCTION: SwissProt: Q8TDS4 # Acts as a high affinity receptor for nicotinic acid and mediates its anti-lipolytic effect through a G(i)-protein-mediated inhibition of adenylyl cyclase. This pharmacological effect requires nicotinic acid doses that are much higher than those provided by a normal diet.
SIZE: 363 amino acids; 41850 Da
SUBCELLULAR LOCATION: Cell membrane; Multi-pass membrane protein.
TISSUE SPECIFICITY: Expression largely restricted to adipose tissue and spleen.
SIMILARITY: SwissProt: Q8TDS4 ## Belongs to the G-protein coupled receptor 1 family.
MISCELLANEOUS: The rank order of potency for the displacement of nicotinic acid binding is 5-methyl pyrazole-3-carboxylic acid = pyridine-3-acetic acid > acifran > 5-methyl nicotinic acid = acipimox > nicotinuric acid = nicotinamide.

Human

SPECIFICATIONS: 1 unit = 5 μg
EC50 in GTPγS binding assay by Nicotinic Acid: ~ 3.65 μM

Chem-4

Chemicon

ASSAY CONDITIONS: Membranes are permeabilized by addition of saponin to an equal concentration by mass, then mixed with [³⁵S]-GTPγS (final concentration of 0.3 nM) in 20 mM HEPES, pH 7.4/100 mM NaCl/10 mM MgCl2/0.5 μM GDP in a nonbinding 96-well plate. Unlabeled nicotinic acid was added to the final concentration indicated in Figure 1 (final volume 100 μL), and incubated for 30 min at 30°C. The binding reaction is transferred to a GF/B filter plate (Millipore MAHF B1H) previously prewetted with water, and washed 3 times (1 mL per well per wash) with cold 10 mM sodium phosphate, pH 7.4. The plate is dried and counted.

One vial contains enough membranes for at least 200 assays (units), where one unit is the amount of membrane that will yield greater than 1000 cpm specific nicotinic acid-stimulated [³⁵S]-GTPγS binding.

The GPR109A membrane preparation is expected to be functional in a radioligand binding assay; however, the end user will need to determine the optimal radiolabeled ligand for use with this product.

Chem-4

Liquid in packaging buffer: 50 mM Tris pH 7.4, 10% glycerol and 1% BSA no preservatives.
Packaging method: Membranes protein were adjusted to 1 mg/ml in 1 ml packaging buffer, rapidly frozen, and stored at -80°C

GPR109A

Membranes

Q8TDS4

non-peptide

Nicotinic Acid

Maintain frozen at -70°C for up to 2 years. Do not freeze and thaw.

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A

• GPR109A
• HM74a
• HM74A
• PUMAG
• Puma-g
• HM74b

GPCR Membrane Preparations

ChemiSCREEN™ Membrane Preparation Recombinant Human GPR109A Receptor

NM_177551.3

GPCR