ChemiSCREEN Membrane Preparation Recombinant Human PK ₂ Prokineticin Receptor

Full-length human GPR73L1 cDNA encoding PK₂

Prokineticins, also known as endocrine gland vascular endothelial growth factors (EG-VEGF), are two ~10 kD secreted proteins originally described to mediate angiogenesis and gastrointestinal smooth muscle contraction (Li et al., 2001; LeCouter et al., 2003). Subsequently, prokineticins have been found to mediate central nervous system functions including circadian rhythms and olfactory bulb development (Cheng et al., 2002; Ng et al., 2005). Two G_q-coupled receptors, PK₁ and PK₂ (also known as GPR73a and GPR73b), mediate cellular responses to prokineticins (Lin et al., 2002). Millipore′s PK₂ 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 agonists and antagonists at PK₂. The membrane preparations exhibit a K_d of 0.36 nM for [¹²⁵I]-MIT-1. With 0.3 nM [¹²⁵I]-MIT-1, 10μg/well PK₂ Membrane Prep typically yields greater than 5-fold signal-to-background ratio.

Human PK2 / PKR2 GPCR membrane preparation for Radioligand binding Assays & GTPγS binding.

Radioligand binding assay and GTPγS binding.

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] MIT-1 (Perkin Elmer#: NEX-410)

Wash Buffer: 50 mM Hepes, pH 7.4, 500mM NaCl , 0.1% BSA, filtered and stored at 4°C.

One package contains enough membranes for at least 200 assays (units), where a unit is the amount of membrane that will yield greater than 5-fold signal:background with ¹²⁵I-labeled MIT-1 at 0.3 nM

Liquid in packaging buffer: 50 m

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

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