External ID: FATTTLab-Algae-Lipid

Protocol: Cells were pre-grown to mid-log phase in TAP media. For primary screen, cells were seeded at low density of 500,000 / well in 384-well plate. Compound in DMSO was added to each well at a final concentration of 10 micromolar and cells were allowed to grow for 72 hours. At the end of assay, Nile Red (30 uM f.c.) was added and plates were incubated at 37 C for 60 mins in dark. Fluorescence intensity was measured. Readouts were reported as normalized fold change in the intensity of treated versus control.

Comment: Reference:
1. Wase, N., Tu, B., Black, P. N. & DiRusso, C. C. Phenotypic screening identifies Brefeldin A/Ascotoxin as an inducer of lipid storage in the algae Chlamydomonas reinhardtii. Algal Research 11, 74-84 (2015).

2. Identification and metabolite profiling of chemical activators of lipid accumulation in green algae
#Nishikant Wase, Boqiang Tu, James W Allen, Paul N Black, Concetta C DiRusso
#Plant Physiology Jun 2017, pp.00433.2017; DOI: 10.1104/pp.17.00433
#http://www.plantphysiol.org/content/early/2017/06/26/pp.17.00433

Patent:
DiRusso, C., & Wase, N. (2016). Compounds for Increasing Lipid Synthesis and Storage. United States#NUtech Ventures (Lincoln, NE, US) http://www.freepatentsonline.com/y2016/0312253.html

For additional Information please contact:

Prof. Concetta C. DiRusso
Department of Biochemistry
University of Nebraska-Lincoln
cdirusso2@unl.edu

Nishikant Wase, PhD
Department of Biochemistry
University of Nebraska-Lincoln
nishikant.wase@gmail.com

External ID: 20130627FPNS3INTERFERECB

Protocol: Assay Overview:

The purpose of this biochemical assay is to determine the ability of compounds in a ChemBridge compound library to interfere with the fluorescence signal of a Cy5-labeled substrate oligonucliotide of the hepatitis C non-structural protein 3 helicase (NS3h). In this biochemical assay, the fluorescence of a single strand of DNA with a 5' Cy5 fluorophore (Cy5-dT15) incubated with NS3h and test compound is monitored.

Protocol Summary:

Assays were performed in 20 uL in 384-well black small-volume microplates. All assays contained 5 nM Cy5-dT15 DNA (5'- Cy5 TT TTT TTT TTT TTT T -3'), 15 nM NS3h, 25 mM MOPS, pH 7.5, 1.25 mM MgCl2, 0.0025 mg/ml BSA, 0.005% (v/v) Tween 20, and 0.025 mM DTT. Compounds dissolved in DMSO were added at final concentration of 0.1mM and a final DMSO concentration of 1% (v/v). Cy5 fluorescence was read. Interference was calculated according to the equation below.

Interference = Fc / F[-]

Where:

Fc is the fluorescence in the presence of the compound
F[-] is the average fluorescence negative controls

Any compound that exhibited an interference value greater than 0.8 or less than 1.2 was considered inactive. Any compound that exhibited an interference value greater than or equal to 1.2 was considered active (a fluorescent enhancer) in the assay and will not be pursued further. Any compound that exhibited an interference value less than or equal to 0.8 was considered active (a fluorescent quencher) in the assay and will not be pursued further.

List of Reagents:

Cy5-dT15 (Integrated DNA Technologies Inc, custom synthesized)
dT20 (Integrated DNA Technologies Inc, custom synthesized)
MOPS (Fisher Scientific, part BP308-100)
Magnesium Chloride (Fisher Scientific, part BP214-500)
384-well plates (Greiner Bio-One, black, part 784076)

Comment: The assay was performed and submitted by the Frick Lab at the University of Wisconsin-Milwaukee. The compounds tested in this assay were from a ChemBridge compound library.

External ID: CBX7-Alpha-primary

Protocol: The protocol for the CBX7 AlphaScreen that we use is as follows: We create a standard alpha buffer (50mM HEPES, 150mM NaCl, 0.1% w/v BSA, 0.01% w/v Tween20) at pH 8.0 and make up two stock solutions at 2x final concentration in the alpha buffer. Solution A contains Human His6-CBX7 is used with biotinylated-H3K27me3 (residues 20-34), at 100nM and 50nM respectively. Solution B contains 20nM streptavidin donor beads and 20nM nickel acceptor beads. For 384 well assay formats, 10uL of solution A is added to each well of the assay plate and the plate is spun at 1000 rpm for 30 seconds. 100 nL of experimental ccompounds from stock plates are delivered by robotic pin transfer using a Janus Workstation (PerkinElmer), allowing the compounds to interact with CBX7 binding prior to assay measurement, followed by another spin and an incubation room temperature. Finally, 10uL of solution B is added to each well, the plate is spun again and then incubated at room temperature. AlphaScreen measurements are performed on an Envision 2104 (PerkinElmer) utilizing the manufacturer's protocol that has the correct excitation and emission wavelengths, cutoff filters, delay time, etc. We also do a crosstalk calculation through the Envision software to correct for luminescence for adjacent wells while reading the plate. The signal is then normalized to DMSO control wells on the compound plate prior to creation of the IC50 curves.

Comment:

External ID: LDHA

Protocol: The assay was optimized to 1536-well plates. Briefly, 3 muL of human lactate dehydrogenase 5 (#A38558H, Meridian Life Science, Inc., Memphis, TN) in LDH assay buffer (200 mM Tris HCl pH 7.4, 100 microM EDTA and 0.01% Tween-20) was added to a black solid bottom 1536-well assay plate (Greiner Bio-One) using a BioRAPTR FRD dispenser (Beckman Coulter, Brea, CA). A 1536-well pintool dispenser outfitted with 20 nL pins (Wako Automation, San Diego, CA) was used to transfer 23 nL of DMSO-solubilized compound (both library and vehicle controls) to each 1536-well assay plate. Following compound transfer, 1 muL of substrate solution containing NADH and sodium pyruvate (Sigma-Aldrich, St. Louis, MO) in LDH assay buffer was dispensed via BioRAPTR FRD to initiate the reaction. Final concentrations in the 4 microL reaction volume were 2 nM LDHA enzyme, 0.06 mM NADH and 0.2 mM sodium pyruvate. Following a 5 minute incubation period at room temperature, 1 muL of detection reagent (C. kluyveri diaphorase (Sigma-Aldrich) and resazurin sodium salt (Sigma-Aldrich) in LDH assay buffer) was added to a total volume of 5 muL. Final concentrations of detection reagents were 0.133 mg/mL diaphorase and 37 muM resazurin. Plates were immediately transferred to a ViewLux microplate imager (PerkinElmer, Waltham, MA), and any resulting resorufin fluorescence was measured (ex540, em590 nm) at 0 and 20 minutes. Fluorescence was normalized using enzyme-free and DMSO-treated control wells on each plate.

Comment: PubChem score indicates % inhibition at 229 uM or 114 uM of the compound (Max_response). Active compounds with Max_response greater than -100%, PUBCHEM_ACTIVITY_SCORE is 100. Active compounds with Max_response between -80% and -100%, PUBCHEM_ACTIVITY_SCORE is 80. Active compounds with Max_response between -60% and -80%, PUBCHEM_ACTIVITY_SCORE is 60. Active compounds with Max_response between -30% and -60%, PUBCHEM_ACTIVITY_SCORE is 40. Inconclusive Compounds with Max_response between -25% and -30% have PUBCHEM_ACTIVITY_SCORE 20. For all inactive compounds with Max_response greater than -25%, PUBCHEM_ACTIVITY_SCORE is 0

External ID: ST2_IL33_Inhibitors_Primary_Screening_77700

Protocol: High-throughput screening was performed at Indiana University screening facility (Indiana University, Indianapolis, IN).

In summary, a mixture of ST2 and IL-33 was prepared by adding 0.30 microL of 14.1 microM recombinant human ST2-Fc Chimera and 0.30 microL of 55.25 biotinylated recombinant human IL-33 to 1.4 mL of assay buffer. In the HTS, each well of a 384-well Proxi-plate was first blocked by 100 microL of assay buffer for 1 h at room temperature. After removing the blocking buffer, 20 microL of ST2/IL-33 mixture was pipetted into each well and incubated at room temperature for 1 h followed by addition of compounds at 17 microM (0.8 microL) to each well and incubated at room temperature for 1 h. Ten microliters of 60 microg/mL anti-6xHis-conjugated AlphaLISA acceptor beads were added to each well and incubated at room temperature for 1 h before addition of 10 microL of 60 microg/mL of streptavidin-labeled AlphaLISA donor beads for incubation at room temperature for 30 min. Incubation of acceptor and receptor beads was conducted in darkness. The well with 3 nM ST2 alone was used as a negative control, whereas the ST2/IL-33 mixture with a human ST2 antibody added at 0.45 ng/microL was used as the positive control. Plates were read using the Envision Plate Reader. The buffer used in the assay contains 14.37 mL PBS, 30 microL Tween 20, and 600 microL of 5% bovine serum albumin in PBS.

Comment: PubChem active indicates >= 30% inhibition of ST2/IL-33 at 17 uM of the compound. Inconclusive: >=10% and < 30% inhibition.

External ID: 20130624FPNS3DACB

Protocol: Assay Overview:

The purpose of this biochemical assay is to determine the ability of compounds in a ChemBridge compound library to displace the hepatitis C non-structural protein 3 helicase (NS3h) from its substrate oligonucleotide. In this biochemical assay, the fluorescence polarization of a single strand of DNA with a 5' Cy5 fluorophore (Cy5-dT15) incubated with NS3h and test compound is monitored. Fluorescence polarization increases when NS3h binds the substrate. As designed, compounds that interfere with binding decrease the fluorescence polarization.

Protocol Summary:

Assays were performed in 20 uL in 384-well black small-volume microplates. All assays contained 5 nM Cy5-dT15 DNA (5'- Cy5 TT TTT TTT TTT TTT T -3'), 15 nM NS3h, 25 mM MOPS, pH 7.5, 1.25 mM MgCl2, 0.0025 mg/ml BSA, 0.005% (v/v) Tween 20, and 0.025 mM DTT. Compounds dissolved in DMSO were added at final concentration of 0.1mM and a final DMSO concentration of 1% (v/v). Cy5 fluorescence polarization was read using a G-factor calculated from a well lacking NS3h or test compounds. Percent inhibition was calculated according to the equation below.

%_Inhibition = 100 - ( ( Fc - F[+]) / (F[-] - F[+] ) ) * 100

Where:

Fc is the fluorescence polarization in the presence of the compound
F[-] is the average fluorescence polarization of no enzyme negative controls
F[+] is the average fluorescence polarization of positive controls (200 nM dT20).

Two values were calculated: (1) the average percent inhibition of all compounds tested, and (2) three times their standard deviation. The sum of these two values was used as a cutoff parameter. Any compound that exhibited greater percent inhibition than the cutoff parameter was considered active.

List of Reagents:

Cy5-dT15 (Integrated DNA Technologies Inc, custom synthesized)
dT20 (Integrated DNA Technologies Inc, custom synthesized)
MOPS (Fisher Scientific, part BP308-100)
Magnesium Chloride (Fisher Scientific, part BP214-500)
384-well plates (Greiner Bio-One, black, part 784076)

Comment: The assay was performed and submitted by the Frick Lab at the University of Wisconsin-Milwaukee. The compounds tested in this assay were from a ChemBridge Library set.

External ID: stopgo-p2-SytraCBC-dual-FF

Protocol: Reagents:
StopGo2A HEK-NPG-Luc cells and other necessary media and controls were provided by Dr. Atkins's lab. Compound PTC124 was used as a control. Dose response was assessed using a 1:2 dilution of control compound, with the top dose of 50uM final concentration. Background signal was normalized to wells treated with DMSO only.

Assay Protocol:
In brief, four microliters (2400 cells/well) of StopGo2A HEK-NPG-Luc cells were plated and incubated overnight at 37C. Twenty-three nanoliters of compounds and control were added to the wells using a 1536 array Kalypsys pintool workstation. After an over night incubation (at 37C) with compounds / control, 2.5 uL of Dual/Glo Firefly reagent was added. Firefly luciferase signal was obtained using the PerkinElmer ViewLux plate reader after 20min of room temperature incubation. Dual/Glo Renilla Lucifrase reagents were then added followed by additional 20 min room temperature incubation. Finally, the renilla luciferase signal was obtained using the PerkinElmer ViewLux reader.

Comment: Disclaimer:
Although all reasonable efforts have been made to ensure the accuracy and reliability of the data, caution should be exercised when interpreting the results as artifacts are possible from nonspecific effects such as assay signal interference. The curve fitting and activity calls presented here are based on the NCATS analysis methods.

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. For this assay, apparent inhibitors are ranked higher than compounds that showed apparent activation.
2. For all inactive compounds, with a ratio activity curve class of 4, 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. For a ratio activity curve class = -1.1, score = 80+abs((log_ac50+4.5)*inf_activity/20). For ratio.curve_class == -1.2 && abs(ratio.max_response) > 6*10, score = 60+abs((log_ac50+4.5)*inf_activity/20). For ratio.curve_class == -2.1 || ( ratio.curve_class==-2.2 && abs(ratio.max_response) > 6*10), score = 40+abs((log_ac50+4.5)*inf_activity/20). For ratio.curve_class == -1.2 || ratio.curve_class == -2.2, score = 20+abs((log_ac50+4.5)*inf_activity/20). Inconclusive compounds, with a donor curve class other than 4, have PUBCHEM_ACTIVITY_SCORE of 10. Inconclusive compounds have PUBCHEM_ACTIVITY_SCORE between 1 and 39.

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%.

External ID: stopgo-p2-SytraCBC-dual-Ren

Protocol: Reagents:
StopGo2A HEK-NPG-Luc cells and other necessary media and controls were provided by Dr. Atkins's lab. Compound PTC124 was used as a control. Dose response was assessed using a 1:2 dilution of control compound, with the top dose of 50uM final concentration. Background signal was normalized to wells treated with DMSO only.

Assay Protocol:
In brief, four microliters (2400 cells/well) of StopGo2A HEK-NPG-Luc cells were plated and incubated overnight at 37C. Twenty-three nanoliters of compounds and control were added to the wells using a 1536 array Kalypsys pintool workstation. After an overnight incubation (at 37C) with compounds / control, 2.5 uL of Dual/Glo Firefly reagent was added. Firefly luciferase signal was obtained using the PerkinElmer ViewLux plate reader after 20min of room temperature incubation. Dual/Glo Renilla Lucifrase reagents were then added followed by additional 20 min room temperature incubation. Finally, the renilla luciferase signal was obtained using the PerkinElmer ViewLux reader.

Comment: Disclaimer:
Although all reasonable efforts have been made to ensure the accuracy and reliability of the data, caution should be exercised when interpreting the results as artifacts are possible from nonspecific effects such as assay signal interference. The curve fitting and activity calls presented here are based on the NCATS analysis methods.

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. For this assay, apparent inhibitors are ranked higher than compounds that showed apparent activation.
2. For all inactive compounds, with a ratio activity curve class of 4, 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. For a ratio activity curve class = -1.1, score = 80+abs((log_ac50+4.5)*inf_activity/20). For ratio.curve_class == -1.2 && abs(ratio.max_response) > 6*10, score = 60+abs((log_ac50+4.5)*inf_activity/20). For ratio.curve_class == -2.1 || ( ratio.curve_class==-2.2 && abs(ratio.max_response) > 6*10), score = 40+abs((log_ac50+4.5)*inf_activity/20). For ratio.curve_class == -1.2 || ratio.curve_class == -2.2, score = 20+abs((log_ac50+4.5)*inf_activity/20). Inconclusive compounds, with a donor curve class other than 4, have PUBCHEM_ACTIVITY_SCORE of 10. Inconclusive compounds have PUBCHEM_ACTIVITY_SCORE between 1 and 39.

External ID: GPR151_PHUNTER_AG_LUMI_1536_1X%ACT

Protocol: Assay Overview:
TThe goal of this NIH sponsored research project was to identify GPR151 agonists via high-throughput screening (HTS) efforts. In brief, the McDonald Lab transferred the GPR151 AG 384wpf assay to Scripps for implementation and miniaturization to 1,536-well format followed by screening against the Scripps Drug Discovery Library (SDDL). A counterscreen assay, employing GPR119 cells, was also implemented by Scripps to identify compounds that non-specifically affect the PathHunter detection method. This project was aided by cheminformatic efforts to help identify compounds that demonstrated authentic agonist pharmacology and non-promiscuous activity profiles across other primary screens run against the SDDL. At completion of the project, several compounds demonstrated activity in the GPR151 AG PathHunter assay. All compounds selected for titration were also subjected to LC-MS analysis to confirm mass and sample purity

Protocol Summary:
Prior to the start of the assay, cells were resuspended in growth media at 2000cells/well in 1536 well plates. This was followed by an incubation of 18 hours at 37C+5%CO2. Then 1uL of Opti-Mem added to all wells except high controls to which 3X EA reagentwas added to each of those wells (0.2X final in lysis buffer). Compounds were pinned at 11.20uM final concentration in 1.0% DMSO followed by a 90 minute incubation at 37C+5%CO2. At this stage 3uL of Promega Beta-Glo detection Buffer was added to all wells followed by a 1 hour incubation at room temperature. Finally the assay end point read was taken using the ViewLux imaging reader from PerkinElemer Lifesciences with a 5 second exposure. Raw assay data was imported into Scripps# corporate database and ascetrained for Z' greater than 0.5 in order to be processed futher.

The percent activation for each compound was calculated as follows:

Percent Response of compound= 100 * ((Test Well-Median Data Wells)/(Median High Control # Median Data Wells))
Where:
Test_Well is defined as wells containing GPR151 cells in the presence of test compound
High_Control represents wells containing GPR151 cells stimulated with 0.2X EA reagent
Low_Control is defined as wells containing GPR151 cells and DMSO
PubChem Activity Outcome and Score:
Standard Cutoff
The reported PubChem Activity Score has been normalized to 100% observed primary inhibition. Negative % inhibition values are reported as activity score zero.
The activity score range for active compounds is 100-1, for inactive 1-0.
List of Reagents:
GPR151 cells (supplied by Patricia McDonald)
Pen Strep (Invtirogen 15140)
FBS (Invtirogen 16140)
Hygromycin (Invtirogen 10687010)
Lysis buffer (CisBio 62CL2FDF)
EA Reagent (DiscoverX 30-411)
G418 (Gemini Bio 400-113)
Opti-MEM (Invtirogen 31985)
Trypsin (Invtirogen 15400054)
Beta Glo (Promega E4780)
1536-well plates (Greiner Bio-One, part 789173)

Comment: Due to the size of the Scripps Molecular Screening Center compound library, this assay have been run as multiple separate campaigns, each campaign testing a unique set of compounds. All data reported were normalized on a per-plate basis. Possible artifacts of this assay can include, but are not limited to: dust or lint located in or on wells of the microtiter plate, compounds that modulate well fluorescence. All test compound concentrations reported above and below are nominal; the specific test concentration(s) for a particular compound may vary based upon the actual sample provided by the Scripps Molecular Screening Center.

A mathematical algorithm was used to determine what we call the standard hit cut-off to identify active compounds. Two values were calculated: (1) the average percent activation of all compounds tested in the screen, and (2) three times their standard deviation. The sum of these two values was used as a cutoff parameter, i.e. any compound that exhibited greater percent activation than the cutoff parameter was declared active. Using this "Standard Cutoff" (= 4.91%) the primary assay yielded 6,756 active compounds ("hits")."

External ID: FBW7_ACT_ALPHA_1536_1X%ACT PRUN

Protocol: Assay Overview:
FBW7 assay principle. In this assay, either mutant or wild type (w.t.) FBW7 interact with phosphorylated cyclin E peptide (cycE~P), which will bring donor and acceptor beads into close proximity. Laser excitation of the donor beads converts oxygen to an excited singlet state. Reaction of the singlet oxygen with the acceptor beads further activates a chemiluminescence/fluorescence reaction within the same bead resulting in emitted light at 520-620 nm. Small molecule activators that enhance the mutant FBW7 interaction with the cycE~P decrease the distance of the acceptor beads, thus leading to increased signal being emitted signal.
Protocol Summary:
There are six steps in this 1536 well assay format which are listed in order. First, 2.5uL/well of a 2X working solution containing RLFbw7 [12.5nM final], Cyclin E peptide [12.5nM final], and Ni beads [5ug/mL final], in assay buffer (25mM Tris-HCl pH 7.4 + 100mM NaCl, 0.1% Tween-20, 5mM ?-Mercaptoethanol and 0.05% BSA) was dispensed into columns 1-44. Then 2.5uL/well of a 2X working solution containing WTFbw7 [12.5nM final], Cyclin E peptide [12.5nM final], and Ni beads [5ug/mL final], in assay buffer was dispensed into columns 45-48. Using the pintool transfer device 134nL of compound or control was added to each well. This achieved a nominal screening concentration of 26.1uM and 2.6% DMSO concentration. This was followed by the addition of SA beads to all wells at 5ug/mL final concentration in assay buffer. The assay was then incubated for 20 hours in a temperature controlled 25C environment followed by Alphascreen detection using the PerkinElmer EnVision.

The percent activation for each compound was calculated as follows:

100 *( ( Test_Compound - Median_Low_Control ) / ( Median_High_Control - Median_Low_Control ) )
Where:
Test_Compound is defined as wells containing RLFbw7 (mutant), cyclin E peptide and Nickel acceptor beads in the presence of test compound
High_Control is defined as wells containing WTFbw7 (wild type), cyclin E peptide and Nickel acceptor beads
Low_Control is defined as the median of the wells containing DMSO, RLFbw7 (mutant), cyclin E peptide and Nickel acceptor beads
PubChem Activity Outcome and Score:

A mathematical algorithm was used to determine active compounds. Two values were calculated: (1) the average percent activation of all compounds tested for the screen, and (2) three times their standard deviation. The sum of these two values was used as a cutoff parameter, i.e. any compound that exhibited greater percent activation than the cutoff parameter (1.85% in the case here) was declared active.
The reported PubChem Activity Score has been normalized to 100% observed primary inhibition. Negative % inhibition values are reported as activity score zero.
The activity score range for active compounds is 100-1, for inactive 1-0.
List of Reagents:
Ni Beads- PerkinEmer Lifesciences Cat#6760619R
RLFbw7-Assay Provider
WTFbw7-Assay Provider
Cyclin E peptide-Assay Provider
5M NaCl- Sigma Cat# S6546-1L
Tween20- Fisher Cat# BP337
Tris 1M pH7.4 Research Organics Cat# 9686T
BSA-Sigma Cat#A7030
?-Mercaptoethanol-SigmaM6250
1536-well plates (Corning, part 7254)

Comment: Due to the size of the Scripps Molecular Screening Center compound library, this assay may have been run as two or more separate campaigns, each campaign testing a unique set of compounds. All data reported were normalized on a per-plate basis. Possible artifacts of this assay can include, but are not limited to: dust or lint located in or on wells of the microtiter plate, compounds that modulate well fluorescence. All test compound concentrations reported above and below are nominal; the specific test concentration(s) for a particular compound may vary based upon the actual sample provided by the Scripps Molecular Screening Center.

External ID: MITF_INH_Alpha_1536_1X%INH PRUN

Protocol: Assay Overview:

The purpose of this biochemical assay is to identify MITF dimerization inhibitors that disrupt or prevent its homodimerization. This assay is a bead-based proximity assay, which employs acceptor beads and donor beads to generate a chemiluminescence signal. In this assay, Biotin-labelled MITF and His- tagged MITF homodimerization will bring donor and acceptor beads into close proximity. Laser excitation of the donor beads converts oxygen to an excited singlet state. Reaction of the singlet oxygen with the acceptor beads further activates a chemiluminescence reaction within the same bead resulting in emitted light at 520-620 nm. As designed, small molecule inhibitors that interfere with this interaction will increase the distance of the acceptor beads, thus leading to decreased signal. Compounds were tested in singlicate at a nominal test concentration of 2.6 micromolar.

Protocol Summary:
Prior to the start of the assay, 1.25#L of assay buffer (50mM HEPEs pH7.5, 250mM Sodium chloride, 0.1% Tween, 0.1% BSA) containing 10nM His-MITF_r259stop were dispensed into columns 1 thru column 2, and 1.25#L of assay buffer containing 10nM of His MBP MITF were dispensed into columns 3 thru column 48 of 1536 microtiter plates. Next, 10nL of test compounds in DMSO, 7,8-Dihydroxycoumarin (200#M final highest concentration) in DMSO, or DMSO alone (0.15% final concentration) were added to the appropriate wells before dispensing 1.25#L of 10#g/mL Acceptor beads into column 1 to 46 and 1.25#L of assay buffer into column 47 and 48. Plates were incubated in dark for 2hrs at room temperature. Then, dispenses of 1.25#L of 10nM Biotin-MITF into all columns, and 10#g/mL Donor beads into column 1 to 46 and 1.25#L of assay buffer into column 47 to 48 followed by 3hrs incubation in dark at RT, was done. Alphascreen signal was determined using an EnVision microplate reader (PerkinElmer, Waltham, MA) at 680nm excitation and 570nm emission.

The percent inhibition for each compound was calculated as follows:

100 *( ( Median_Low Control-Test Compound) / ( Median_Low Control - Median_High Control ) )

Where:

Test_Compound is defined as wells containing His-MITF + Biotin-MITF in the presence of test compound
High_Control is defined as wells containing His-MITF_r259stop + Biotin-MITF and DMSO.
Low_Control is defined as wells containing His-MITF + Biotin-MITF and DMSO

PubChem Activity Outcome and Score:

Standard Cutoff

The reported PubChem Activity Score has been normalized to 100% observed primary inhibition. Negative % inhibition values are reported as activity score zero.

The activity score range for active compounds is 100-1, for inactive 1-0.

List of Reagents:

His-tagged MITF protein (supplied by Min Guo)
His-tagged MITF_r259stop protein (supplied by Min Guo)
Biotinylated-MITF protein (supplied by Min Guo)
7,8-Dihydroxycoumarin (Sigma, part D5564)
HEPEs (Sigma, part H3375, H3784)
Sodium chloride (Fisher, part BP358-212)
Tween-20 (Fisher, part 50146671)
DMSO (Fisher, part D159)
BSA (Fisher, part BP1600-100)
AlphaScreen Beads Kit (Perkin Elmer, part 6760619L)
1536-well plates (Greiner Bio-One, part 789175)

Comment: Due to the size of the Scripps Molecular Screening Center compound library, this assay have been run as multiple separate campaigns, each campaign testing a unique set of compounds. All data reported were normalized on a per-plate basis. Possible artifacts of this assay can include, but are not limited to: dust or lint located in or on wells of the microtiter plate, compounds that modulate well fluorescence. All test compound concentrations reported above and below are nominal; the specific test concentration(s) for a particular compound may vary based upon the actual sample provided by the Scripps Molecular Screening Center.