qHTS for Inhibitors of PI5P4K: ADP-Glo counter assay
Phosphatidylinositol (PI) signaling has been shown to impact a large and diverse set of cellular processes including proliferation, survival, and growth; their dysregulation is common in cancer and other diseases. Recently, PI5P has been shown to regulate the tumor suppressor ING2. In addition to finding PI5P, we discovered the type II phosphatidylinositol 5-phosphate 4-kinase (PI5P4K) family more ..
BioActive Compounds: 2
Phosphatidylinositol (PI) signaling has been shown to impact a large and diverse set of cellular processes including proliferation, survival, and growth; their dysregulation is common in cancer and other diseases. Recently, PI5P has been shown to regulate the tumor suppressor ING2. In addition to finding PI5P, we discovered the type II phosphatidylinositol 5-phosphate 4-kinase (PI5P4K) family (alpha, beta, gamma isoforms) that catalyze the conversion of PI5P to PI(4,5)P2. Alternatively, PI(4,5)P2 can also be synthesized through phosphatidylinositol-4-phosphate (PI4P) by the type I phosphatidylinositol 4-phosphate 5-kinases (PI4P5K). These PI5P4K enzymes therefore represent one way by which cells can regulate endogenous PI5P levels and play important roles in insulin signaling and in stress responses. Furthermore, recent findings have demonstrated a critical role for PI5P4K in tumor cell growth and support a potential role in oncogenesis for PI5P4K.
A qHTS PI5P4K-alpha ADP-Glo assay was developed to identify specific modulators of human PI5P4K, phosphatidylinositol-5-phosphate 4-kinase (Type II PIPK). This assay was screened against the MLSMR containing ~400,000 small molecules (PubChem AID 652105). To confirm that the hits were not interacting with the detection enzyme system, a 1536-well counterscreen against the ADP-Glo kit (Promega) was utilized, as described in Davis et al., 2013 . For this assay, an ATP/ADP mix of 80% ATP and 20% ADP was used to mimic the PI5P4K-alpha enzyme reaction. For a compound that does not interfere with the detection system, there should be no inhibition of the luminescence signal. Therefore, true inhibitors of PI5P4K-alpha should have no activity in this assay.
 Davis et al., PLoS One. 2013;8(1):e54127.
NIH Chemical Genomics Center [NCGC]
NIH Molecular Libraries Probe Centers Network [MLPCN]
MLPCN Grant: MH096575
Assay Submitter (PI): Atsuo Sasaki, Beth Israel Deaconess Medical Center
Two micoliter of assay buffer (0.038 M HEPES pH 7.4, 0.28 mM EGTA, 0.1% CHAPS, 7.5% DMSO) was dispensed into Greiner white solid bottom 1536-well assay plates. Compounds were then transferred via Kalypsys pin tool equipped with 1536-pin array (10 nL slotted pins, V&P Scientific, San Diego, CA). Next, 1 uL of ATP / ADP mix (4 uM ATP / 1 uM ADP final concentrations in 20 mM HEPES pH 7.4, 60 mM MgCl2, and 0.1% CHAPS) was added for a total reaction volume of 3 uL. The plates were incubated at room temperature for 60 minutes. To detect the activity, 2 uL of ADP-Glo reagent 1 was added to each well followed by 45 min room temperature incubation. Then, 4 uL of ADP-Glo reagent 2 was added to each well and the plates were incubated further for 30 min at room temperature. Finally, luminescence signal was detected using the PerkinElmer ViewLux plate reader (30 sec exposure). The data was normalized to control wells with 20% ADP / 80% ATP and wells with 100% ATP.
1. Compounds are first classified as having full titration curves, partial modulation, partial curve (weaker actives), single point activity (at highest concentration only), or inactive. See data field "Curve Description". For this assay, apparent inhibitors are ranked higher than compounds that showed apparent activation.
2. For all inactive compounds, PUBCHEM_ACTIVITY_SCORE is 0. For all active compounds, a score range was given for each curve class type given above. Active compounds have PUBCHEM_ACTIVITY_SCORE between 40 and 100. Inconclusive compounds have PUBCHEM_ACTIVITY_SCORE between 1 and 39. Fit_LogAC50 was used for determining relative score and was scaled to each curve class' score range.
* Activity Concentration. ** Test Concentration.
Data Table (Concise)