AlphaLISA SureFire Ultra Human Phospho-ATR (Thr1989) Detection Kit, 50,000 Assay Points

Phospho-AlphaLISA SureFire Ultra assay principle

The Phospho-AlphaLISA SureFire Ultra assay measures a protein target when phosphorylated at a specific residue.

The assay uses two antibodies which recognize the phospho epitope and a distal epitope on the targeted protein. AlphaLISA assays require two bead types: Acceptor and Donor beads. Acceptor beads are coated with a proprietary CaptSure™ agent to specifically immobilize the assay specific antibody, labeled with a CaptSure tag. Donor beads are coated with streptavidin to capture one of the detection antibodies, which is biotinylated. In the presence of phosphorylated protein, the two antibodies bring the Donor and Acceptor beads in close proximity whereby the singlet oxygen transfers energy to excite the Acceptor bead, allowing the generation of a luminescent Alpha signal. The amount of light emission is directly proportional to the quantity of phosphoprotein present in the sample.

Phospho-AlphaLISA SureFire Ultra two-plate assay protocol

The two-plate protocol involves culturing and treating the cells in a 96-well plate before lysis, then transferring lysates into a 384-well OptiPlate™ plate before the addition of Phospho-AlphaLISA SureFire Ultra detection reagents. This protocol permits the cells viability and confluence to be monitored. In addition, lysates from a single well can be used to measure multiple targets.

Phospho-AlphaLISA SureFire Ultra one-plate assay protocol

Detection of Phosphorylated target protein with AlphaLISA SureFire Ultra reagents can be performed in a single plate used for culturing, treatment, and lysis. No washing steps are required. This HTS designed protocol allows for miniaturization while maintaining AlphaLISA SureFire Ultra quality.

Hydroxyurea induces ATR phosphorylation in a dose-dependent manner

HeLa and A549 cells were seeded in a 96-well plate (40,000 cells/well) in complete medium and incubated overnight at 37°C, 5% CO₂. The cells were treated with increasing concentrations of hydroxyurea for 18 hours.

After treatment, the cells were lysed with 50 µL of Lysis Buffer for 10 minutes at RT with shaking (350 rpm). ATR Phospho (Thr1989) and Total levels were evaluated using respective AlphaLISA SureFire Ultra assays. For the detection step, 10 µL of cell lysate (approximately 8,000 cells) was transferred into a 384-well white OptiPlate, followed by 5 µL of Acceptor mix and incubated for 1 hour at RT. Finally, 5 µL of Donor mix was then added to each well and incubated for 1 hour at RT in the dark. The plate was read on an Envision using standard AlphaLISA settings.

As expected, hydroxyurea triggered a dose-dependent increase in the levels of Phospho (Thr1989) while  Total ATR levels were unchanged.

Etoposide induces ATR phosphorylation

HeLa and A549 cells were seeded in a 96-well plate (40,000 cells/well) in complete medium and incubated overnight at 37°C, 5% CO₂. The cells were treated with increasing concentrations of etoposide for 18 hours.

After treatment, the cells were lysed with 50 µL of Lysis Buffer for 10 minutes at RT with shaking (350 rpm). ATR Phospho (Thr1989) and Total levels were evaluated using respective AlphaLISA SureFire Ultra assays. For the detection step, 10 µL of cell lysate (approximately 8,000 cells) was transferred into a 384-well white OptiPlate, followed by 5 µL of Acceptor mix and incubated for 1 hour at RT. Finally, 5 µL of Donor mix was then added to each well and incubated for 1 hour at RT in the dark. The plate was read on an Envision using standard AlphaLISA settings.

As expected, etoposide triggered a dose-dependent increase in the levels of Phospho (Thr1989) while Total ATR levels were unchanged.

Induction of ATR phosphorylation in bleomycin treated cells

HeLa cells were seeded in a 96-well plate (40,000 cells/well) in complete medium and incubated overnight at 37°C, 5% CO₂. The cells were treated with increasing concentrations of bleomycin for 18 hours.

After treatment, the cells were lysed with 50 µL of Lysis Buffer for 10 minutes at RT with shaking (350 rpm). ATR Phospho (Thr1989) and Total levels were evaluated using respective AlphaLISA SureFire Ultra assays. For the detection step, 10 µL of cell lysate (approximately 8,000 cells) was transferred into a 384-well white OptiPlate, followed by 5 µL of Acceptor mix and incubated for 1 hour at RT. Finally, 5 µL of Donor mix was then added to each well and incubated for 1 hour at RT in the dark. The plate was read on an Envision using standard AlphaLISA settings.

Bleomycin triggered a dose-dependent increase in the levels of Phospho (Thr1989) while Total ATR levels were unchanged.