ION Biosciences

Multiplexing GPCR Signaling Pathways with Spectrally Resolved Fluorescent Dyes

Miguel Torres — Fri, 05 Jun 2026 03:52:25 +0000

Simultaneously measure calcium signaling and GIRK activation using Fluo-Gold and Thallos on the CLARIOstar® Plus.

Understanding the complex interactions of G protein-coupled receptor (GPCR) signaling pathways is critical for advancing drug discovery and biomedical research.

In this collaborative application note, ION Biosciences and BMG LABTECH demonstrate the successful detection of two distinct GPCR signaling casecades using spectrally resolved fluorescent dyes. By combining Fluo-Gold AM and Thallos AM on the CLARIOstar® Plus platform, researchers can monitor calcium release induced by Gq agonism and potassium channel activitation by the beta/gamma subunits of Gi GPCRs in real time within the same well.

A multiplexed approach can help you uncover biased ligands and simultaneously promotes faster outcomes in your GPCR discovery campaign.

KEY BENEFITS

Monitor Multiple Signaling Pathways Simultaneously

Measure two distinct GPCR signaling pathways in the same well for more complete SAR.

Spectral Resolution

The PHERAstar FSX provides ultimate flexibility for discriminating between dyes.

Double the Data Output

Capturing two data points simultaneously saves time and resources.

Reduce Profiling Time

Generate richer datasets in fewer experiments to accelerate compound characterization and screening workflows.

Assay Principle

Cells expressing M3 and D2 receptors along with GIRK channels are loaded with Fluo-Gold AM and Thallos AM dyes.

Stimulation with acetylcholine activates the M3 receptor and triggers calcium release, while dopamine activates the D2 receptor and induces potassium flux through GIRK channels. Using spectrally resolved fluorescent dyes, both signaling pathways can be measured simultaneously in real time.

This approach can be translated to other GPCR secondary messenger and fluorescent sensor pairs within our portfolio.

Advance Your GPCR Research with Multiplex Signaling Analysis

Download the full application note to explore the experimental workflow, optimization strategy, and complete results.

Download Application Note (PDF)

Innovative Dyes for Ion Channel Research

High-quality fluorescent dyes designed for accurate and reliable measurements.

High Performance and Reliability

Trusted by researchers worldwide for consistent, reproducible results.

Trusted by Researchers Worldwide

Supporting scientific discovery in academia and industry globally.

Expert Support for Drug Discovery

Out team is here to help you succeed at every stage of your research.

Brilliant Thallium Snapshot kit validated for endpoint potassium assays

Miguel Torres — Thu, 28 May 2026 15:18:43 +0000

Discover how BMG LABTECH validated the Brilliant Thallium Snapshot kit for endpoint potassium channel screening on their PHERAstar FSX multi-mode plate reader.

Download Application Note (PDF)

In this collaborative Application Note with BMG LABTECH, ION’s Brilliant Thallium Snapshot kit demonstrated results comparable to kinetic imaging readers using the PHERAstar FSX multi-mode plate reader. This simplified endpoint assay workflow provides a cost-effective alternative for potassium channel screening without requiring specialized kinetic imaging systems.

Endpoint assay, simplified

Thallium flux measured in an endpoint format—no kinetic imaging reader required.

Comparable to FLIPR

Concentration-response results on the PHERAstar FSX are comparable to kinetic imaging (FLIPR) systems.

Optimized for HTS

Validated in 1536-well plates for high-throughput screening campaigns.

Cost-effective alternative

A more accessible solution that expands potassium channel screening to more labs.

Comparable performance to kinetic imaging readers

Read the full Application Note

Get the full experimental details, optimization data, and screening results in this collaborative study with BMG LABTECH.

Download Application Note (PDF)

Questions about this application?

Get the full experimental details, optimization data, and screening results in this collaborative study with BMG LABTECH.

Enquire Now

Comprehensive Assay Collection for TMEM175 Drug Discovery

Miguel Torres — Wed, 03 Dec 2025 19:40:38 +0000

TMEM175 as a Target for Drug Discovery

TMEM175 is a lysosomal ion channel that functions as both a proton channel and potassium channel. It plays a crucial role in maintaining lysosomal pH, and is essential for lysosomal function. Mutations in TMEM175 lead to impaired lysosomal degradation and increased neuronal susceptibility to alpha-synuclein aggregation, and are associated with an increased risk of developing Parkinson’s disease.

Validated TMEM175 Assays

Gain exclusive insights for your Parkinson’s disease pipeline with our suite of proprietary assays to identify TMEM175 inhibitors and activators. Our TMEM175 services are supported by the most expansive collection of HTS assays to deliver valuable information about how your compounds interact with this disease relevant lysosomal target. All assays generate EC50 values in line with literature reported values for known tool compounds, ensuring data reliability from day to day. Our validated cell line and robust assay platforms can be leveraged to assess what you need, from ion permeability profiling to inhibitor identification.

If you’re searching for TMEM175 variants or additional readouts to support your research, our team can help.

Thallium-free Potassium Channel Assay

Proprietary ION technology that measures potassium efflux through activated TMEM175 channels expressed on the plasma membrane in real time. DCPIB and 4-AP are used to demonstrate a robust hit identification capability. The measurement of potassium yields physiologically relevant data for TMEM175 when compared to other surrogate readouts.

GO TO PRODUCT

Brilliant Thallium Assay

Gold standard for potassium channel drug discovery. Thallium acts as a surrogate for potassium ions to probe TMEM175 channel activity. This solution is able to identify activators and inhibitors of TMEM175, but requires longer compound incubation times to generate a robust response.

GO TO PRODUCT

Brilliant Thallium Snapshot Assay

Proprietary ION technology that measures thallium efflux in response to TMEM175 activation. This assay produces the largest screening window of all available assays, and can be used to identify activators or inhibitors. TMEM175 activation is visualized in real time upon stimulation with DCPIB.

GO TO PRODUCT

Brilliant Intracellular pH Assay

Measures proton transport through TMEM175 upon activation with DCPIB. As a predominantly proton channel on its native lysosomal membrane, this physiologically relevant readout can help you identify compounds that alter the proton conductance of TMEM175.

Lysosomal TMEM175 Assays

Powered by our Halotag-compatible thallium indicator collection, we’ve enabled HTS of TMEM175 activity expressed on lysosomal membranes inside viable, intact cells. Available in 384-well plate formats for high-throughput drug discovery campaigns. No lysosomal manipulation or isolation required. Probe TMEM175 in its native membrane and environment to get the most relevant insights into target engagement and TMEM175 pharmacology.

Lysosomal Thallium Flux Assay

Our proprietary thallium dye is localized to the lumen of lysosomes to measure thallium flux across the lysosomal membrane in intact cells. Enables the identification of activators, such as DCPIB, and inhibitors, like 4-AP, of lysosomal TMEM175 using standard HTS methods (384-well format).

ION Thallos Gold-HTL loaded lysosomes

Sample activator and inhibitor data using our lysosomal drug discovery platform for TMEM175 assays. Included data are normalized kinetic traces (top left), a dose response curve to DCPIB (top right), and a dose response curve to 4-AP in TMEM175 expressing cells and wild-type cells (bottom left).

Lysosomal pH Assay

Immunofluorescence series of cells stained with pH-HTL, a TMEM175 antibody, and hoechst (a nuclear stain).

Using a custom pH-sensitive dye that is also a ligand for Halotag (pH-HTL), we can localize the pH indicator to the lumen of lysosomes. From there, we measure proton flux across the lysosomal membrane in intact cells. This technology enables the identification of activators, such as DCPIB, and inhibitors, like 4-AP, of lysosomal TMEM175 proton conductance using standard HTS methods (384-well format). The assay can be conducted using HTS instrumentation or high content imaging platforms for spatial resolution and realtime visualization of lysosomal pH.

Affect of Bafilomycin A on luminal lysosomal pH with TMEM175 overexpression and DCPIB treatment.

Timelapse of pH-HTL and TMR (pH-insensitive) labeled lysosomes after DCPIB treatment displaying an obvious shift from red to green, indicative of alkalization of the lysosomal lumen.

This platform can also be used to explore additional modulators of lysosomal pH, a crucial regulatory mechanism for lysosomal function, autophagy, and nutrient transport. Transporters including proton pumps (e.g. V-ATPase, SLC7A11), SLC transporters (e.g. SLC15A3 and SLC15A4), and lysosomal ion channels such as TPC2 (two-pore channel 2), all play a role in maintaining or using the lysosomal pH gradient.

Summary

Whether you are screening for TMEM175 modulators or exploring unique pharmacology, our TMEM175 platform offers proprietary insights, maximum throughput, readout flexibility, and physiologically relevant data to support your discovery needs.

Dive deep into TMEM175 pharmacology with us

INQUIRE

High-throughput technologies for Gi GPCR drug discovery

Manuel Pacheco — Tue, 02 Dec 2025 16:37:50 +0000

New Case Study:

Introduction

G protein–gated inwardly rectifying potassium (GIRK) channels strongly shape neuronal and cardiac excitability and, in the brain, mainly form Kir3.1/Kir3.2 heterotetramers activated by Gβγ released from Gi/o-coupled GPCRs, making GIRK activity a direct, physiological readout of Gi/o signaling. Traditional Gi/o assays such as FRET, BRET, or cAMP measurements are limited by pathway complexity or depend on artificial adenylate cyclase stimulation. Here we present a scalable Gi/o GPCR platform for high-throughput, real-time GIRK quantification using both fluorescence and automated patch clamp. The assay uses HEK293 cells stably expressing Kir3.1/3.2 and allows just-in-time transient expression of diverse Gi/o-coupled GPCRs. GIRK activation by ML297 produced comparable EC50 values across fluorescence and electrophysiology, and receptor-driven responses were absent in control HEK cells lacking M2 or GIRK. Overall, this method enables reproducible pharmacology across many neurotransmitter receptors and supports discovery of modulators of Gi/o-linked GPCRs.

Gi GPCR Assay Platform

Stable cell line over-expressing GiRK channels that enables:

Fluorescence and automated electrophysiology-based readouts bridge the gap from hit identification to validation workflows, all at high throughput
Transient GPCR expression using plasmids, lentivirus, or bacmam vectors for maximum flexibility and fast turnaround times

This cross-platform screening technology gives reliable results to accelerate your next discoveries.

Characterizing Gi GPCRs using high throughput fluorescence and electrophysiology based assays for drug discovery

Manuel Pacheco — Mon, 17 Nov 2025 21:31:03 +0000

ION Biosciences Sodium Channel Assays

Manuel Pacheco — Wed, 29 Oct 2025 17:34:05 +0000

Explore the only sodium-selective, sodium channel assays on the market, designed for on-target hit identification. Formatted for high-throughput discovery of voltage-gated sodium channel inhibitors and modulators of ligand-gated channels.

ION Biosciences Potassium Channel Assays

Manuel Pacheco — Wed, 29 Oct 2025 17:23:09 +0000

Access the most expansive collection of fluorescence-based potassium channel assays. From revolutionary thallium-free assays to proprietary thallium flux assays that outperform the competition, find the ideal solution for your purpose.

ION Biosciences Calcium Channel Assays

Manuel Pacheco — Wed, 29 Oct 2025 17:19:46 +0000

Discover the most popular calcium assays and indicators alongside proprietary offerings that span the visible spectrum to fit nearly every application. Whether your target is ion channels or GPCRs, ION Biosciences has a solution for your experiment.

SLC Transporter Assay Services

Manuel Pacheco — Mon, 22 Sep 2025 20:09:58 +0000

Fluorescence-based screening for SLC transporters to unlock substrate affinities, identify
modulators, and de-risk your lead compounds early. Leverage safer technologies with
higher-throughput in living cells, that measure real-time transport kinetics for complete
compound profiling.

Ion Channel Assay Services

Manuel Pacheco — Mon, 22 Sep 2025 19:21:32 +0000

Fluorescence-based, high throughput screening & compound profiling for
ligand- and voltage-gated ion channels—powered by proprietary technology to
drive hit ID, hit validation, and lead optimization decisions.

GPCR Assay Services

Manuel Pacheco — Mon, 22 Sep 2025 18:55:56 +0000

Real-time sensors for dynamic compound profiling of G , G ,
and G coupled receptors to discover agonists, antagonists, and
allosteric modulators. Powered by in-house assay platforms
and state-of-the-art instrumentation for unparalleled insights
to accelerate your discovery programs.

Custom Synthesis Services

Manuel Pacheco — Mon, 22 Sep 2025 18:53:05 +0000

Accelerate your work with custom fluorescent probes and conjugatable ion indicators built in-house by ION’s
organic chemists—delivered to match your timeline and budget. Our team can also align synthesis with assay
development and screening for a seamless path from idea to validated chemistry.

Assay Development Services

Manuel Pacheco — Mon, 22 Sep 2025 18:35:33 +0000

Fluorescence-based assay development from the team that designs & commercializes proprietary assays for ion channels,
transporters, and GPCRs—combining in-house assay technologies, cell line engineering expertise, and advanced
instrumentation to deliver actionable data.

Thallium- Free Potassium Channel Assay

Manuel Pacheco — Fri, 05 Sep 2025 17:16:21 +0000

Direct, real-time K+ flux without thallium or radiolabeling for high-throughput drug discovery

BAPTA JF™549

Manuel Pacheco — Fri, 05 Sep 2025 17:16:07 +0000

A High-Performance Red Calcium Indicator for Optogenetics
and Live-Cell Calcium Imaging

Sodium dependent SLC transporter assay

Manuel Pacheco — Fri, 05 Sep 2025 17:15:49 +0000

A High-Throughput Solution for Measuring the Activity of SLC
Transporters that cotransport sodium ions

SLC6 Transporter Assay Measuring Sodium Flux

Manuel Pacheco — Mon, 02 Jun 2025 21:48:33 +0000

Validated hERG Cell Line for Cardiac Safety Screening

Manuel Pacheco — Tue, 01 Apr 2025 17:25:24 +0000

Explore how our CHO-K1 Kv11.1 (hERG) recombinant cell line was validated for use in Automated Patch Clamp (APC) electrophysiology using the SyncroPatch 384 from Nanion Technologies. This application note highlights high-throughput cardiac safety testing capabilities, pharmacological validation with known hERG inhibitors, and key electrophysiological properties

ION Channel GPCR Services

Manuel Pacheco — Fri, 27 Dec 2024 18:44:27 +0000

Discover ION Biosciences’ drug discovery services, including assay development, high-throughput screening (HTS), and converting hits to leads for ion channels, GPCRs, and transporters

ION Product Catalog 2024

Manuel Pacheco — Fri, 27 Dec 2024 18:38:10 +0000

Download ION Biosciences’ comprehensive 2024 product catalog featuring advanced ion indicators, ion channel assays, GPCR assays, cell-based solutions, and customizable assay kits for cutting-edge drug discovery and research

Targetable ION Indicators

Manuel Pacheco — Fri, 27 Dec 2024 18:31:13 +0000

Explore ION Biosciences’ targetable ion indicators for localized ion channel assays. Leverage Halotag®-binding technology for high-throughput screening and precise targeting of individual cells or organelles

Why ION Biosciences

Manuel Pacheco — Fri, 27 Dec 2024 18:22:03 +0000

Explore why ION Biosciences is a leader in drug discovery tools. From superior fluorescence based assays to custom high throughput screening and chemistry services, we deliver cost-effective solutions with proven reliability and exceptional technical support.