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BioAssay: AID 1711

Concentration-Response Counterscreen for Tau: Redox Active Inhibitors of Caspase-1

The microtubule-associated protein tau is an abundant protein in the axons of neurons that stabilizes microtubules. With its ability to modulate microtubule dynamics, tau contributes directly or indirectly, to key structural and regulatory cellular functions. Particularly important is the influence tau exerts on axonal transport, which allows signaling molecules, trophic factors and other more ..
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 Tested Compounds
 Tested Compounds
All(22)
 
 
Active(2)
 
 
Inactive(17)
 
 
Inconclusive(3)
 
 
 Tested Substances
 Tested Substances
All(23)
 
 
Active(2)
 
 
Inactive(18)
 
 
Inconclusive(3)
 
 
AID: 1711
Data Source: NCGC (TAU2333)
BioAssay Type: Confirmatory, Concentration-Response Relationship Observed
Depositor Category: NIH Molecular Libraries Probe Production Network
Deposit Date: 2009-05-04

Data Table ( Complete ):           View Active Data    View All Data
Target
Sequence: RecName: Full=Caspase-1; Short=CASP-1; AltName: Full=Interleukin-1 beta convertase; Short=IL-1BC; AltName: Full=Interleukin-1 beta-converting enzyme; Short=IL-1 beta-converting enzyme; Short=ICE; AltName: Full=p45; Contains: RecName: Full=Caspase-1 subunit p20; Contains: RecName: Full=Caspase-1 subunit p10; Flags: Precursor
Description ..   
Protein Family: CASc

Gene:CASP1     Related Protein 3D Structures     More BioActivity Data..
BioActive Compounds: 2
Related Experiments
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AIDNameTypeProbeComment
1460qHTS for Inhibitors of Tau Fibril Formation, Thioflavin T BindingConfirmatory depositor-specified cross reference
1468qHTS for Inhibitors of Tau Fibril Formation, Fluorescence PolarizationConfirmatory depositor-specified cross reference
1475Quantitative High-Throughput Screen for Inhibitors of Tau Fibril Formation: SummarySummary1 depositor-specified cross reference
1463Counterscreen qHTS for Inhibitors of Tau Fibril Formation, Fluorescence PolarizationConfirmatory same project related to Summary assay
1558Confirmation Concentration-Response Assay for for Inhibitors of Tau Fibril Formation, Thioflavin T BindingConfirmatory same project related to Summary assay
1559Confirmation Concentration-Response Assay for Inhibitors of Tau Fibril Formation, Fluorescence PolarizationConfirmatory same project related to Summary assay
1694Confirmation Concentration-Response Assay for Inhibitors of Tau Fibril Formation, Total Fluorescence Counterscreen for Fluorescence PolarizationConfirmatory same project related to Summary assay
1709Assay for Inhibitors of Tau-Mediated Microtubule AssemblyOther same project related to Summary assay
1712Assay for Inhibitors of the fibrillization of the Beta-Amyloid Protein Fragment, A-beta 1-42Confirmatory same project related to Summary assay
1719Transmission Electron Microscopy Assay for Inhibitors of Tau FibrillizationOther same project related to Summary assay
1720Sedimentation Assay for Inhibitors of Tau FibrillizationOther same project related to Summary assay
Description:
NIH Molecular Libraries Probe Production Network [MLPCN]
NIH Chemical Genomics Center [NCGC]

MLPCN Grant: X01 MH083262-01
Assay Provider: Carlo Ballatore, University of Pennsylvania


NCGC Assay Overview:
The microtubule-associated protein tau is an abundant protein in the axons of neurons that stabilizes microtubules. With its ability to modulate microtubule dynamics, tau contributes directly or indirectly, to key structural and regulatory cellular functions. Particularly important is the influence tau exerts on axonal transport, which allows signaling molecules, trophic factors and other essential cellular constituents to travel along the axons. Under pathological conditions, tau becomes sequestered into insoluble aggregates called neurofibrillary tangles. This phenomenon is believed to have pathological consequences by promoting axonal transport deficits that ultimately lead to synaptic dysfunction and neuronal loss. To examine the selectivity of tau fibrillization inhibitors, compounds were tested in an in vitro assay for caspase-1 activity. This assay is a counterscreen for tau fibrillization inhibitors to identify non-specific oxidizing agents; an active site cysteine in caspase-1 must remain in a reduced state and the enzyme is inactivated by oxidative compounds. Caspase-1 activity was monitored using a profluorescent substrate that upon enzymatic cleavage yields a fluorescent probe that is detectable at 405 nm excitation and 525 nm emission.

Scheer, J. M., Wells, J. A., and Romanowski, M. J. (2005) Protein Expression and Purification 41, 148-153.
Protocol
NCGC Assay Protocol Summary:
Caspase-1, kindly provided by Dr. James Wells (University of California, San Francisco), was purified and assayed at 100 nM in buffer containing 50 mM HEPES pH 7.5, 50 mM KCl, 200 mM NaCl, and 0.1% CHAPS. Caspase-1 was dispensed at 3 uL/well into black solid 1536-well plates and incubated 5 min with various concentrations of test compound, with subsequent addition of 1 ul/well Ac-WEHD-AFC substrate (20 uM final concentration). Within 1 minute of substrate addition, fluorescence intensity (405 nm excitation and 525 nm emission) was measured on a ViewLux (PerkinElmer) every 30 s for 10 min. The first 3 minutes of fluorescence values were linear and used to calculate the slope of substrate conversion as a measure of enzyme activity.
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.
Categorized Comment - additional comments and annotations
From ChEMBL:
Assay Type: Functional
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
5Curve_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
6Fit_LogAC50The logarithm of the AC50 from a fit of the data to the Hill equation (calculated based on Molar Units).Float
7Fit_HillSlopeThe Hill slope from a fit of the data to the Hill equation.Float
8Fit_R2R^2 fit value of the curve. Closer to 1.0 equates to better Hill equation fit.Float
9Fit_InfiniteActivityThe asymptotic efficacy from a fit of the data to the Hill equation.Float%
10Fit_ZeroActivityEfficacy at zero concentration of compound from a fit of the data to the Hill equation.Float%
11Fit_CurveClassNumerical encoding of curve description for the fitted Hill equation.Float
12Excluded_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
13Max_ResponseMaximum activity observed for compound (usually at highest concentration tested).Float%
14Activity at 0.0000009689 uM (9.68893e-07μM**)% Activity at given concentration.Float%
15Activity at 0.0000027404 uM (2.74044e-06μM**)% Activity at given concentration.Float%
16Activity at 0.0000054809 uM (5.48089e-06μM**)% Activity at given concentration.Float%
17Activity at 0.0000069866 uM (6.9866e-06μM**)% Activity at given concentration.Float%
18Activity at 0.0000139732 uM (1.39732e-05μM**)% Activity at given concentration.Float%
19Activity at 0.0000279464 uM (2.79464e-05μM**)% Activity at given concentration.Float%
20Activity at 0.0000777153 uM (7.77153e-05μM**)% Activity at given concentration.Float%
21Activity at 0.0002172065 uM (0.000217207μM**)% Activity at given concentration.Float%
22Activity at 0.0004344131 uM (0.000434413μM**)% Activity at given concentration.Float%
23Activity at 0.0008688262 uM (0.000868826μM**)% Activity at given concentration.Float%
24Activity at 0.00174 uM (0.00173765μM**)% Activity at given concentration.Float%
25Activity at 0.00348 uM (0.0034753μM**)% Activity at given concentration.Float%
26Activity at 0.00695 uM (0.00695061μM**)% Activity at given concentration.Float%
27Activity at 0.014 uM (0.0139012μM**)% Activity at given concentration.Float%
28Activity at 0.028 uM (0.0278024μM**)% Activity at given concentration.Float%
29Activity at 0.056 uM (0.0556049μM**)% Activity at given concentration.Float%
30Activity at 0.111 uM (0.11121μM**)% Activity at given concentration.Float%
31Activity at 0.222 uM (0.22242μM**)% Activity at given concentration.Float%
32Activity at 0.453 uM (0.45345μM**)% Activity at given concentration.Float%
33Activity at 0.916 uM (0.915748μM**)% Activity at given concentration.Float%
34Activity at 1.831 uM (1.8315μM**)% Activity at given concentration.Float%
35Activity at 3.663 uM (3.66299μM**)% Activity at given concentration.Float%
36Activity at 7.184 uM (7.18391μM**)% Activity at given concentration.Float%
37Activity at 14.37 uM (14.3678μM**)% Activity at given concentration.Float%
38Activity at 40.64 uM (40.6383μM**)% Activity at given concentration.Float%
39Compound QCNCGC designation for data stage: 'qHTS', 'qHTS Verification', 'Secondary Profiling'String

* Activity Concentration. ** Test Concentration.
Additional Information
Grant Number: X01 MH083262-01

Data Table (Concise)
Data Table ( Complete ):     View Active Data    View All Data
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