External ID: HMS1303

Protocol: Prior to screening, lyophilized FITC-GIV peptide (a.a. 1671-1701) is dissolved in 100% DMSO to a concentration of 0.5 mM, then further diluted with water to a final concentration of 50 microM. One stock was prepared in batch for the entire screen and aliquoted. All protein stocks were stored at -80C. Thawing of aliquots on the day of the assay was performed rapidly at room temperature.

Prior to transfer of screening compounds, experimental wells of 384-well assay plates were pre-filled with 37.8 nM of FITC-GIV peptide (for 25 nM final concentration) in a 10 microL volume of assay buffer (50 mM Tris [pH 7.4], 100 mM NaCl, 10 mM MgCl2, 5 mM EDTA, 0.4% NP-40, 30 microM GDP, 1 mM DTT). Control wells were pre-filled with 37.8 nM of FITC-GIV peptide in 10 microL of assay buffer containing either 1% DMSO (vehicle negative control) or 45.3 microM AlCl3+15.1 mM NaF (AlF4- positive control). Each plate contained 16 negative control and 16 positive control wells. Plates were centrifuged at 1000xg for 2 minutes to eliminate bubbling on the surface. Following, 100 nL of experimental compound was pin-transferred into individual wells for each of two replicate assay plates (A&B). After pin-transfer, 5 microL of 3 microM His-tagged rat Galphai3 purified from E. coli (for 1 microM final concentration) was added to each well, and assay plates were shaken at low speed for 5 seconds. Final assay volume was 15 microL. Plates were centrifuged at 1000xg for 2 minutes to eliminate bubbling on the surface and shaken for 10 seconds prior to an incubation of 90 minutes at room temperature. Plates were protected from prolonged light exposure. All manipulations were performed at room temperature.

Assay plates were read with a PerkinElmer Wallac EnVision Multilabel 2103 plate reader using the fluorescent polarization measurement technology with a D505fp/D535 dual mirror and a 480 nm excitation filter. 535 nm emission filters were used for P and S channel reads at 11 mm measurement height with 30 flashes and detector gains of 319 and 563. G-factor 0.96.

Negative control: DMSO
Positive control: Aluminum tetrafluoride (AlF4-, composite of NaF and AlCl3)

Comment: Calculated result values and scoring of active compounds:

Z-score: Indicates the number of standard deviations an experimental condition is from the mean. It is calculated based on plate average (u) and standard deviation (s) of experimental well fluorescence polarization (FP) measurements for each replicate. Z-score (z) is defined as the quotient of the mean of the experimental well population subtracted from an individual well's FP (x), divided by the standard deviation within the experimental wells; z = (x-u)/s.

Normalized percent control: calculated by subtracting plate average positive control FP from experimental well FP, dividing by the difference between plate average negative and positive control FP, and multiplying by 100.

STD: the number of standard deviations from the plate average negative control FP for each replicate experimental well

Compound wells with FP values exceeding +5 standard deviations from the negative control sample average were flagged as potential aggregators or fluorescence quenchers due to their high polarization signal (HighPol) and were excluded from further consideration. Activity scores were calculated by averaging the replicate normalized percent of control values and subtracting from 100 (score based on single replicate if data for other replicate was excluded for any reason). Result values < 0 were set to 0 (no activity) and > 100 were set to 100 (100% activity). Compounds with activity score >= 15 were considered active.

External ID: KUHTS-Muma KU-CaM-Htt INH-01

Protocol: 1; Dispense 45 nl compounds (10 mM stocks) using ECHO 555 to Alpha 384 well assay plates. Dispense 45 nl DMSO to control columns 1 and 2 of 384 well plates.
2; Incubate 5 ul of 6XHis-mHTT (Final, 13 nM) with the compounds for 40 mins at room temperature in buffer containing 10 mM Tris.HCl pH 7.4, 1 mM calcium chloride, 150 mM sodium chloride, 0.1% BSA and 20% glycerol.
3; Dispense 5 ul of 6XGST-CaM (Final 13 nM) in buffer A.
4; Incubation; 1 hour (dark at 25C)
5; Dispense 20 ul of Nickel chelate acceptor beads (Final, 20 ugs/ml) and Glutathione donor beads (Final, 30 ugs/ml). Incubate for 2h, room temperature.
6; Detector: Perkin Elmer Enspire, Alphascreen Module (Excitation 680nm/Emission 570nm).

NOTES (numbers refer to Sequence numbers above)
1. Alphascreen bead incubations were performed in green light, TiterTek setting 400rpm.
2. All incubation and addition steps were followed by mixing and centrifugation at 400g,1 min.
3. The percent inhibition for each compound was calculated as follows:
100- [100 *((Test Compound-Median Low Control) / (Median High Control - Median Low Control))]

Where:
Test_Compound is defined as wells containing His mHTT + GST CaM in the presence of test compound

High_Control is defined as wells containing His mHTT + GST CaM and DMSO.

Low_Control is defined as wells containing His mHTT and DMSO.

Comment: All percent inhibition data reported were normalized to high and low controls on a per-plate basis. The results of primary screening data include compounds contributing to assay signal interference, interference with tags binding to Alpha beads, chelators, process related artifacts etc.. The actives were defined as compounds that inhibited Alphascreen reads to greater than 50%.