Targeting the cGAS-STING Pathway Using a Homogenous, HTS Compatible Transcreener cGAS Assay

cGAS Assay Method

Ordering Information

Assay Services

Related Resources

Transcreener cGAMP cGAS Assay

Transcreener cGAMP cGAS Assay directly measures cyclic GMP-AMP (cGAMP) produced by cyclic GMP-AMP synthetase (cGAS, C6orf150, 2'3'-cGAMP Synthetase). These cGAMP measurements allow researchers to effectively determine the enzyme's activity. The assay provides a powerful tool to screen compound libraries for cGAS modulators to help find new therapies for disease.

The kit comes complete with the detection reagents required to measure activity. cGAS enzyme is not included in the inhibitor screening assay kit. Recombinant cGAS enzyme is available for separate purchase through BellBrook labs.

Important Messenger in the STING Pathway

DNA in the cytosol of eukaryotic cells indicates infection or cellular damage, and it elicits a robust immune response, driven by type I interferon (IFN) induction.

cGAS is an exquisitely sensitive sensor for double-stranded DNA in the cytoplasm. Binding of DNA activates the enzyme to produce a unique cyclic dinucleotide second messenger, cGAMP, which acts as an agonist for the STING (stimulator of interferon genes) receptor, leading to induction of a type I interferon response.

How Does This cGAS Assay Work?

The Transcreener cGAMP cGAS Assay determines cGAS enzyme activity by directly measuring the cGAMP formed by the enzyme using the Transcreener cGAMP Assay. By detecting cGAMP output, the assay provides a universal method to assess the activity of any cGAMP-producing enzyme in real-time.

Transcreener cGAMP Assay technology uses a simple but highly effective method that consists of an antibody selective to cGAMP and a far-red fluorescent tracer. cGAMP produced in the reaction competes with the tracer changing the fluorescent properties and providing fluorescent readout.

The cGAS assay is available with FP and TR-FRET. It is a simple mix-and-read format. Perform your enzyme reaction, add the detection reagent, and measure. The simplicity of the system yields robust results that also makes it extremely amiable to HTS.

Direct Detection of cGAMP to Measure cGAS Enzymatic Activity

Fluorescent Polarization (FP)

Learn More About The FP Assay

Transcreener cGAMP FP Assay Tech Manual

Time-Resolved Förster Resonance Energy Transfer (TR-FRET)

Learn More About The TR-FRET

Transcreener cGAMP TR-FRET Assay Tech Manual

Applications

Measure Enzymatic Activity of cGAS
Screen Compound Libraries for cGAS inhibitors
Quantify Inhibitor Potency
Determine Inhibitor-cGAS Residence Time

Features

Direct detection of unlabeled cGAMP
Easy to use, homogenous, one step format
Robust Assay Z’ > 0.7 under initial velocity conditions
Far-red fluorescent readouts minimize compound interference
A safe, non-radioactive method
Available in FP or TR-FRET readouts

Easy-to-Use, Mix-and-Read, HTS-Ready Assay

Run your enzyme reaction, add Transcreener reagents, and read your plates. The cGAS assay is compatible with 96, 384, and 1536-well formats.

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Outstanding Signal Stability

The assay exhibits 24 hours+ signal stability. Plate stability like this is vital for sizeable high throughput screens that take significant time to complete due to massive sample quantity.

Standard curves include ATP, GTP, dsDNA, and titration of cGAMP. The same plate was read at each time point.

Detection of cGAMP Under cGAS Initial Velocity

The assay demonstrates linearity when raw data is converted to cGAMP using a standard curve. cGAS is activated by double-stranded DNA and requires ATP and GTP substrates for the production of cGAMP.

Full-Length Human cGAS Titration

Linear Response

cGAS Enzyme Titration Initial Velocity Conditions

Screen for Inhibitors & Perform SAR

The Transcreener cGAS Assay is designed for screening compound libraries in a high throughput format. Follow up SAR can also be performed using the assay to determine inhibitor potency with ease.

1600 Compound Pilot Screen

Acquire Accurate Dose Response Measurements

Illustrates DNA & Substrate Dependance of the cGAS Enzyme

The assay accurately demonstrates the characteristics of the cGAS enzyme. Double-stranded DNA activates the enzyme which generates cGAMP in the presence of both GTP and ATP. A 45 base pair ISD (interferon stimulatory DNA) and a 60 base pair HSV (herpes simplex virus) DNA both activate the enzyme. The assay has a high affinity to cGAMP and can detect even in the presence of other nucleotides.

cGAS Enzyme Activation by dsDNA

Dependence on ATP and GTP

BellBrook Lab's Recombinant cGAS Enzyme

Active, full-length Human Cyclic GMP-AMP synthase enzyme, His-tagged protein expressed and purified from E.coli. The enzyme has been thoroughly validated with Transcreener cGAS Activity Assays. For specific activity, please refer to the Certificate of Analysis for each individual enzyme lot. Purity is >90% in a 20mM Tris 7.5, 200mM NaCl, 1mM DTT, 10% glycerol buffer composition. The enzyme is currently used in the Transcreener cGAS Activity Assay at 30 nM, which is 1.75 μg/mL (17.5 ng in 10 µL enzyme reaction volume in a 384-well format). Please adjust the enzyme concentration based on your requirements.

Go to Human cGAS Enzyme Page

cGAS Assay Services

Interested in moving your program forward, but don't want to bring an assay in-house? Our scientists can help! BellBrook scientists will use their extensive biochemistry and enzymology expertise to work with you and accelerate your cGAS program.

Lead Discovery Services Include:

Inhibitor Screening – To identify or confirm activity with the target.
Inhibitor Potency Profiling – Dose-response with target and/or related proteins. Fast IC₅₀ results.
Residence Time Measurements – Determination of k_off using ‘jump dilution’ enzymatic assay method.
Mechanism of Action Studies – Kinetic analysis to define the mode of inhibition.

Contact Us to Learn More

Please fill out the form below. We will respond quickly to get the conversation moving and learn how we can help. We keep things discrete, confidential, and professional.

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Far-Red FP & TR-FRET Readouts Validated on Major Multimode Readers

Instrument	FP Assays	TR-FRET Assays
TriStar²S LB 942	in review	validated
Mithras² LB 943	in review	validated

Cytation™ 5	validated	validated
Cytation™ 3	validated	validated
Cytation™ 1	validated	validated
Synergy™ H1	validated	validated
Synergy™ 2/H4/4	validated	validated
Synergy™ HTX	not capable	not capable
Synergy™ Neo 2	validated	validated

POLARstar^® Omega	validated	validated
FLUOstar^® Omega	not capable	validated
PHERAstar^® FSX	validated	validated
PHERAstar^® Plus/FS	validated	validated
CLARIOstar^® /Plus	validated	validated

Analyst^® GT/HT	validated	validated
Gemini^® XPS/EM	not capable	not capable
SpectraMax^® M2/M2e	not capable	not capable
SpectraMax^® M5/M5e/FlexStation^® 3	not capable	validated
SpectraMax^® Paradigm	validated	contact us
SpectraMax^® iD3/iD5	in review	validated

EnVision^®/EnVision^® Xcite	validated	validated

Infinite^® M1000/M1000Pro/Safire2™	validated	validated
Infinite^® M200	not capable	not capable
Infinite^® F500	validated	validated
Infinite^® F200/Ultra^evolution	contact us	contact us
Spark™ 10M	validated	validated

What's Included


Component	Notes
cGAMP Antibody	Antibody specific to the dinucleotide cGAMP.
Tracer	When displaced, changes in fluorescence can be read in an FP or TR-FRET depending on the assay format.
Stop & Detect Buffer B, 10X	A buffer that can be used to stop enzyme reactions for an endpoint readout.
ATP	ATP can be used for the enzyme reaction and standard curve.
GTP	GTP can be used for the enzyme reaction and standard curve.
cGAMP	cGAMP can be used to create a standard curve.
Interferon Stimulatory DNA	ISD is a 45-bp oligomer used to activate the cGAS enzyme.

What You Will Need


Component	Notes
cGAS Enzyme	You can purchase active *cGAS enzyme* directly through BellBrook Labs.
Enzyme Buffer	We routinely use enzyme buffer containing 20 mM TRIS (pH 7.5), 5 mM MgCl₂, 0.01% Brij-35, and 1% DMSO (test compound solvent). Use the buffer that is a best fit for your enzyme conditions
Assay Plates	You can purchase assay plates directly through BellBrook Labs. FP - An entirely black plate with a non-binding surface is required. We suggest Corning 384-well plates, Cat. #4514. TR-FRET - An entirely white plate with a non-binding surface is required. We suggest Corning 384-well plates Cat. #4513
Plate Reader	A multi-detection plate reader configured to measure the output of the cGAMP tracer is required.
Enzyme Buffer	Use liquid handling devices that can accurately dispense sub-microliter volumes into 384-well plates.
Ultrapure Water	Some deionized water systems are contaminated with nucleases that can degrade both nucleotide substrates and products, reducing assay performance. Careful handling and use of ultrapure water eliminates this potential problem.

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Transcreener cGAMP cGAS Assay Kits

* For custom or bulk orders (over 100,000 wells) please contact us (info@bellbrooklabs.com) for a quote.


Cat. No.	Product Description	Price	Add to Cart
3024-1K	Transcreener cGAMP cGAS FP Assay (1,000 Assay, 384 Well)	$798.00	Add to Cart
3024-10K	Transcreener cGAMP cGAS FP Assay (10,000 Assay, 384 Well)	$4,615.00	Add to Cart
3024-100K	Transcreener cGAMP cGAS FP Assay (10 X 10,000 Assay, 384 Well)	$23,075.00	Add to Cart
3025-1K	Transcreener cGAMP cGAS TR-FRET Assay (1,000 Assay, 384 Well)	$875.00	Add to Cart
3025-10K	Transcreener cGAMP cGAS TR-FRET Assay (10,000 Assay, 384 Well)	$4,989.00	Add to Cart
3025-100K	Transcreener cGAMP cGAS TR-FRET Assay (10 X 10,000 Assay, 384 Well)	$24,950.00	Add to Cart

cGAS Enzyme Ordering Information

* For custom or bulk orders (over 100 μg) please contact us (info@bellbrooklabs.com) for a quote.


Cat. No.	Product Description	Price	Add to Cart
2227	Recombinant cGAS Enzyme, Active, Human, Full-Length, 10 µg	$399.00	Add to Cart
2228	Recombinant cGAS Enzyme, Active, Human, Full-Le ngth, 100 µg	$1,398.00	Add to Cart

cGAS Screening Bundles

* Includes enough enzyme for respective wells when used at 1.75 μg/mL (30 nM)


Cat. No.	Product Description	Price	Add to Cart
3024-1K-B	Includes Transcreener cGAS FP Assay 1K Kit and 20 µg Human cGAS Enzyme	$1,275.00	Add to Cart
3024-10K-B	Includes Transcreener cGAS FP Assay 10K Kit and 200 µg Human cGAS Enzyme	$6,670.00	Add to Cart
3025-1K-B	Includes Transcreener cGAS TR-FRET Assay 1K Kit and 20 µg Human cGAS Enzyme	$1,345.00	Add to Cart
3025-10K-B	Includes Transcreener cGAS TR-FRET Assay 10K Kit and 200 µg Human cGAS Enzyme	$6,995.00	Add to Cart

Assay Plates for FP

Edit
Cat. No.	Product Description	Price
2233	Corning 96-Well Black Assay Plates (#3686), 3-Pack (200+ Assays)	$50.00	Add to Cart
2229	Corning 384-Well Black Assay Plates (#4514), 3-Pack (1,000+ Assays)	$55.00	Add to Cart
2230	Corning 384-Well Black Assay Plates (#4514), 30-Pack (10,000+ Assays)	$449.00	Add to Cart

Assay Plates for TR-FRET

Cat. No.	Product Description	Price
2234	Corning 96-Well White Assay Plates (#3642), 3-Pack (200+ Assays)	$50.00	Add to Cart
2231	Corning 384-Well White Assay Plates (#4513), 3-Pack (1,000+ Assays)	$60.00	Add to Cart
2232	Corning 384-Well White Assay Plates (#4513), 30-Pack (10,000+ Assays)	$499.00	Add to Cart

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The Role of cGAS As a Therapeutic Target

cGAS recognizes foreign double-stranded DNA and initiates an innate immune response, called the cGAS-STING pathway. cGAS can cause tissue or autoimmune diseases if overactivated by the body's abnormal DNA. Examples of diseases caused by this include Aicardi-Goutières syndrome, systemic lupus erythematosus, and primary biliary liver disease (Li et al, 2021).

The cGAS-STING pathway is an attractive target for autoimmune diseases and cancers. Transcreener's cGAMP cGAS Assay is an excellent tool for researchers examining the therapeutic effects of cGAS.

Transcreener® cGAMP cGAS Assay

Targeting the cGAS-STING Pathway Using a Homogenous, HTS Compatible Transcreener cGAS Assay

cGAS Assay Method

Ordering Information

Assay Services

Related Resources

Transcreener cGAMP cGAS Assay

Important Messenger in the STING Pathway

How Does This cGAS Assay Work?

Direct Detection of cGAMP to Measure cGAS Enzymatic Activity

Fluorescent Polarization (FP)

Time-Resolved Förster Resonance Energy Transfer (TR-FRET)

Applications

Features

Easy-to-Use, Mix-and-Read, HTS-Ready Assay

Outstanding Signal Stability

Detection of cGAMP Under cGAS Initial Velocity

Full-Length Human cGAS Titration

Linear Response

Screen for Inhibitors & Perform SAR

1600 Compound Pilot Screen

Acquire Accurate Dose Response Measurements

Illustrates DNA & Substrate Dependance of the cGAS Enzyme

cGAS Enzyme Activation by dsDNA

Dependence on ATP and GTP

BellBrook Lab's Recombinant cGAS Enzyme

cGAS Assay Services

Lead Discovery Services Include:

Contact Us to Learn More

Far-Red FP & TR-FRET Readouts Validated on Major Multimode Readers

What's Included

What You Will Need

Transcreener cGAMP cGAS Assay Kits

cGAS Enzyme Ordering Information

cGAS Screening Bundles

Assay Plates for FP

Assay Plates for TR-FRET

The Role of cGAS As a Therapeutic Target

Related Resources