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BioAssay: AID 652168

qHTS for Inhibitors of Ubiquitin-specific Protease USP2a Using CHOP2 as the Reporter: K633 Counterscreen

Homeostasis of cellular proteins is maintained through a combination of synthesis and degradation. The pathway that accounts for the majority of protein degradation is the ubiquitin-proteasomal pathway. Ubiquitin (Ub) is highly conserved in all cells and the generation of a multi-Ub chain typically targets proteins for degradation by the proteasome. However, ubiquitination is highly reversible more ..
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 Tested Compounds
 Tested Compounds
All(297)
 
 
Inactive(196)
 
 
Inconclusive(102)
 
 
 Tested Substances
 Tested Substances
All(307)
 
 
Inactive(205)
 
 
Inconclusive(102)
 
 
 Related BioAssays
 Related BioAssays
AID: 652168
Data Source: NCGC (USP2604)
BioAssay Type: Confirmatory, Concentration-Response Relationship Observed
Depositor Category: NIH Molecular Libraries Probe Production Network
Deposit Date: 2013-03-25
Hold-until Date: 2014-03-24
Modify Date: 2014-03-25

Data Table ( Complete ):           All
Tested Compounds:
Depositor Specified Assays
AIDNameTypeComment
2281qHTS Assay for Inhibitors of Ubiquitin-specific Protease USP2a: SummarysummarySummary AID
Description:
Homeostasis of cellular proteins is maintained through a combination of synthesis and degradation. The pathway that accounts for the majority of protein degradation is the ubiquitin-proteasomal pathway. Ubiquitin (Ub) is highly conserved in all cells and the generation of a multi-Ub chain typically targets proteins for degradation by the proteasome. However, ubiquitination is highly reversible and dynamic. Deubiquitination, the reverse process, is catalyzed through the action of enzymes referred to as isopeptidases or deubiquitinating enzymes (DUBs) [1, 2]. This group of enzymes is collectively responsible for maintaining adequate pools of free ubiquitin and regulating the ubiquitination status of cellular proteins. The class of DUBs referred to as the ubiquitin-specific proteases (USP) family functions endoproteolytically to cleave Ub chains from a wide range of protein substrates. USP2a deubiquitinates fatty acid synthase (FASN) which has recently been identified as an emerging oncology target. To identify inhibitors of USP2a a cell-free qHTS assay was employed.

To determine whether the compounds interacted with the detection system alone, the effect of compounds on the substrate of assay 2.1.3 over time was determined in a 1536-well assay. A compound that modulates the fluorescence over time would be indicative of interference with the detection system. The buffer consisted of 20 mM Tris pH 8, 2 mM beta-mercaptoethanol and 0.05% Chaps, and the assay was run in black solid-bottom Greiner plates.

NIH Molecular Libraries Probe Centers Network [MLPCN]
NIH Chemical Genomics Center [NCGC]

MLSCN Grant: MH079852
PI Name: Benjamin Nicholson, Progenra Inc, Malvern, PA
Protocol
3 uL of no enzyme in assay buffer was dispensed into a 1536-well plate and then compounds were added through pinning. 1 uL of 100 nM DiUb K48-4IQF subtsrate was added before fluoresence on the ViewLux in kinetic moder (Ex 525/Em 598).
Comment
Compound Ranking:

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.
Result Definitions
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TIDNameDescriptionHistogramTypeUnit
OutcomeThe BioAssay activity outcomeOutcome
ScoreThe BioAssay activity ranking scoreInteger
1PhenotypeIndicates type of activity observed: inhibitor, activator, fluorescent, cytotoxic, inactive, or inconclusive.String
2Potency*Concentration at which compound exhibits half-maximal efficacy, AC50. Extrapolated AC50s also include the highest efficacy observed and the concentration of compound at which it was observed.FloatμM
3EfficacyMaximal efficacy of compound, reported as a percentage of control. These values are estimated based on fits of the Hill equation to the dose-response curves.Float%
4Analysis CommentAnnotation/notes on a particular compound's data or its analysis.String
5Activity_ScoreActivity score.Integer
6Curve_DescriptionA description of dose-response curve quality. A complete curve has two observed asymptotes; a partial curve may not have attained its second asymptote at the highest concentration tested. High efficacy curves exhibit efficacy greater than 80% of control. Partial efficacies are statistically significant, but below 80% of control.String
7Fit_LogAC50The logarithm of the AC50 from a fit of the data to the Hill equation (calculated based on Molar Units).Float
8Fit_HillSlopeThe Hill slope from a fit of the data to the Hill equation.Float
9Fit_R2R^2 fit value of the curve. Closer to 1.0 equates to better Hill equation fit.Float
10Fit_InfiniteActivityThe asymptotic efficacy from a fit of the data to the Hill equation.Float%
11Fit_ZeroActivityEfficacy at zero concentration of compound from a fit of the data to the Hill equation.Float%
12Fit_CurveClassNumerical encoding of curve description for the fitted Hill equation.Float
13Excluded_PointsWhich dose-response titration points were excluded from analysis based on outlier analysis. Each number represents whether a titration point was (1) or was not (0) excluded, for the titration series going from smallest to highest compound concentrations.String
14Max_ResponseMaximum activity observed for compound (usually at highest concentration tested).Float%
15Activity at 0.0009732759 uM (0.000973276μM**)% Activity at given concentration.Float%
16Activity at 0.00292 uM (0.00291983μM**)% Activity at given concentration.Float%
17Activity at 0.00876 uM (0.00875954μM**)% Activity at given concentration.Float%
18Activity at 0.026 uM (0.0262786μM**)% Activity at given concentration.Float%
19Activity at 0.079 uM (0.0788357μM**)% Activity at given concentration.Float%
20Activity at 0.237 uM (0.236507μM**)% Activity at given concentration.Float%
21Activity at 0.710 uM (0.709522μM**)% Activity at given concentration.Float%
22Activity at 2.129 uM (2.12857μM**)% Activity at given concentration.Float%
23Activity at 6.386 uM (6.3857μM**)% Activity at given concentration.Float%
24Activity at 19.16 uM (19.1571μM**)% Activity at given concentration.Float%
25Activity at 57.47 uM (57.4713μM**)% Activity at given concentration.Float%
26Compound QCNCGC designation for data stage: 'qHTS', 'qHTS Verification', 'Secondary Profiling'String

* Activity Concentration. ** Test Concentration.
Additional Information
Grant Number: MH079852

Data Table (Concise)
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