Assay Method Information

Assay Name:  pAKT Protocol
Description:  Inhibition of the PI3K-AKT-mTOR pathway was measured by quantifying the loss of (Ser-473) pAKT using AlphaScreen (Perkin Elmer). B103 (Rat Neuroblastoma) cells were seeded in serum containing medium (High Glucose DMEM (-Phenol Red)+10% FBS+2× Glutamax+1 mM Sodium Pyruvate+10 mM HEPES+1× Non-Essential Amino Acids+1× Pen/Strep) on a 96-well tissue culture treated plate and grown for 20 hours. Cells were then serum starved in serum free medium (High Glucose DMEM (-Phenol Red)+1× Glutamax+1 mM Sodium Pyruvate+1× Pen/Strep) for 6 hours prior to a 2-hour pretreatment with inhibitors of the pathway, including reference inhibitor LY294002. These inhibitors were prepared at a 200× final concentration as a 6-point, 1:3 serial dilution in DMSO series, with DMSO as the 7th point. The inhibitors were then diluted in experimental medium (High Glucose DMEM (-Phenol Red)+1× Glutamax+1 mM Sodium Pyruvate+1× Pen/Strep+25 mM HEPES+0.1% BSA) and combined with the cells at 1× final concentration in 0.5% DMSO. The cells were then stimulated for 20 minutes with (2.5 μg/mL) insulin, an activator of the PI3K-AKT-mTOR pathway and a demonstrated (Ser-473) pAKT agonist. Cells were promptly lysed using Perkin Elmer proprietary lysis buffer and the (Ser-473) pAKT and total AKT contained in the lysate was measured by AlphaScreen. In AlphaScreen, donor beads were coated with streptavidin to capture one of the antibodies, which is biotinylated. Acceptor beads were coated with Protein A to immobilize the other antibody. In the presence of target protein, the two antibodies bring the donor and acceptor beads close together, generating signal. The amount of light emission is directly proportional to the amount of target protein present in the sample. For each inhibitor tested: the ratio of measured (Ser-473) pAKT/totalAKT was plotted in GraphPad Prism as a 7-point, non-linear regression, 4-parameter curve with bottom constrained to reference control bottom and unconstrained top anchored to DMSO.
Affinity data for this assay
 

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