Toolkit/M2R fluorescence-based biosensor panel

M2R fluorescence-based biosensor panel

Construct Pattern·Research·Since 2026

Also known as: fluorescence-based biosensors for M2 muscarinic acetylcholine receptor, M2R biosensors

Taxonomy: Mechanism Branch / Architecture. Workflows sit above the mechanism and technique branches rather than replacing them.

Summary

Here we use genetic code expansion and bioorthogonal labelling to generate a panel of fluorescence-based biosensors for a prototypical GPCR, the M2 muscarinic acetylcholine receptor (M2R). These biosensors enable real-time monitoring of agonist-promoted conformational changes across the receptor's extracellular surface in intact cells.

Usefulness & Problems

Why this is useful

This biosensor panel reports agonist-promoted conformational changes across the extracellular surface of M2R in intact cells in real time.; real-time monitoring of agonist-promoted GPCR conformational changes in intact cells; probing extracellular-surface conformational changes of M2R; linking ligand-dependent receptor states to G-protein activation behavior

Source:

This biosensor panel reports agonist-promoted conformational changes across the extracellular surface of M2R in intact cells in real time.

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real-time monitoring of agonist-promoted GPCR conformational changes in intact cells

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probing extracellular-surface conformational changes of M2R

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linking ligand-dependent receptor states to G-protein activation behavior

Problem solved

It addresses the question of whether multiple GPCR receptor states occur in living cells and how ligand efficacy is encoded there.; enables observation of multiple receptor conformational states in living cells; provides live-cell readout of GPCR activation trajectories

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It addresses the question of whether multiple GPCR receptor states occur in living cells and how ligand efficacy is encoded there.

Source:

enables observation of multiple receptor conformational states in living cells

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provides live-cell readout of GPCR activation trajectories

Problem links

enables observation of multiple receptor conformational states in living cells

Literature

It addresses the question of whether multiple GPCR receptor states occur in living cells and how ligand efficacy is encoded there.

Source:

It addresses the question of whether multiple GPCR receptor states occur in living cells and how ligand efficacy is encoded there.

provides live-cell readout of GPCR activation trajectories

Literature

It addresses the question of whether multiple GPCR receptor states occur in living cells and how ligand efficacy is encoded there.

Source:

It addresses the question of whether multiple GPCR receptor states occur in living cells and how ligand efficacy is encoded there.

Published Workflows

Ligand-specific activation trajectories dictate GPCR signalling in cells.

2026

Objective: Generate live-cell fluorescence biosensors for M2R and use them to resolve ligand-dependent conformational states and activation trajectories linked to G-protein activation and selectivity.

Why it works: The workflow is presented as working because genetically encoded and bioorthogonally labelled fluorescence biosensors allow real-time monitoring of agonist-promoted conformational changes across the receptor extracellular surface in intact cells.

agonist-dependent conformational equilibriamultiple active states of G-protein-bound M2Rligand-specific activation trajectoriesgenetic code expansionbioorthogonal labellingfluorescence-based biosensor generation

Stages

  1. 1.
    Generate fluorescence-based M2R biosensor panel(library_build)

    To create receptor biosensors capable of reporting conformational changes in intact cells.

    Selection: Construction of a panel of fluorescence-based biosensors using genetic code expansion and bioorthogonal labelling.

  2. 2.
    Real-time live-cell conformational monitoring(functional_characterization)

    To observe receptor conformational changes in living cells rather than relying only on purified in vitro systems.

    Selection: Monitor agonist-promoted conformational changes across the receptor extracellular surface in intact cells.

  3. 3.
    Resolve ligand-specific active-state equilibria and trajectories(secondary_characterization)

    To connect observed conformational behavior to efficacy encoding and G-protein selectivity.

    Selection: Determine how different agonists produce distinct active-state equilibria and activation trajectories of G-protein-bound M2R.

Taxonomy & Function

Primary hierarchy

Mechanism Branch

Architecture: A reusable architecture pattern for arranging parts into an engineered system.

Techniques

No technique tags yet.

Target processes

No target processes tagged yet.

Input: Chemical

Implementation Constraints

cofactor dependency: cofactor requirement unknownencoding mode: genetically encodedimplementation constraint: context specific validationoperating role: sensorswitch architecture: uncaging

The abstract states that the biosensors are generated using genetic code expansion and bioorthogonal labelling.; requires genetic code expansion; requires bioorthogonal labelling

The abstract does not show that this biosensor strategy is generalized beyond the prototypical M2R system.; described for a prototypical GPCR, M2R, in the provided evidence

Validation

Cell-freeBacteriaMammalianMouseHumanTherapeuticIndep. Replication

Supporting Sources

Ranked Claims

Claim 1capabilitysupports2026Source 1needs review

The M2R fluorescence-based biosensor panel enables real-time monitoring of agonist-promoted conformational changes across the receptor extracellular surface in intact cells.

These biosensors enable real-time monitoring of agonist-promoted conformational changes across the receptor's extracellular surface in intact cells.
Claim 2kinetic mechanismsupports2026Source 1needs review

Formation of M2R-G-protein complexes occurs over 0.2-5 s along trajectories involving both common and ligand-specific conformational changes that appear to determine G-protein selectivity.

The formation of these M2R-G-protein complexes occurs over 0.2-5 s along trajectories that involve both common and ligand-specific conformational changes and appear to determine G-protein selectivity.
complex formation time 0.2-5 s
Claim 3mechanistic findingsupports2026Source 1needs review

Different agonists produce equilibria of at least four distinct active states of the G-protein-bound M2R, and these states differ in their ability to activate G proteins.

We demonstrate that different agonists produce equilibria of at least four distinct active states of the G-protein-bound M2R, each with a different ability to activate G proteins.
distinct active states 4

Approval Evidence

1 source3 linked approval claimsfirst-pass slug m2r-fluorescence-based-biosensor-panel
Here we use genetic code expansion and bioorthogonal labelling to generate a panel of fluorescence-based biosensors for a prototypical GPCR, the M2 muscarinic acetylcholine receptor (M2R). These biosensors enable real-time monitoring of agonist-promoted conformational changes across the receptor's extracellular surface in intact cells.

Source:

capabilitysupports

The M2R fluorescence-based biosensor panel enables real-time monitoring of agonist-promoted conformational changes across the receptor extracellular surface in intact cells.

These biosensors enable real-time monitoring of agonist-promoted conformational changes across the receptor's extracellular surface in intact cells.

Source:

kinetic mechanismsupports

Formation of M2R-G-protein complexes occurs over 0.2-5 s along trajectories involving both common and ligand-specific conformational changes that appear to determine G-protein selectivity.

The formation of these M2R-G-protein complexes occurs over 0.2-5 s along trajectories that involve both common and ligand-specific conformational changes and appear to determine G-protein selectivity.

Source:

mechanistic findingsupports

Different agonists produce equilibria of at least four distinct active states of the G-protein-bound M2R, and these states differ in their ability to activate G proteins.

We demonstrate that different agonists produce equilibria of at least four distinct active states of the G-protein-bound M2R, each with a different ability to activate G proteins.

Source:

Comparisons

Source-stated alternatives

The abstract contrasts this live-cell biosensor approach with prior biophysical studies using purified GPCRs in vitro.

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The abstract contrasts this live-cell biosensor approach with prior biophysical studies using purified GPCRs in vitro.

Source-backed strengths

works in intact cells; supports real-time monitoring; captures ligand-dependent conformational differences

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works in intact cells

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supports real-time monitoring

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captures ligand-dependent conformational differences

Compared with bacterial degrons

M2R fluorescence-based biosensor panel and bacterial degrons address a similar problem space.

Shared frame: same top-level item type; same primary input modality: chemical

Compared with mixed quinoline-pyridine aromatic oligoamide helical foldamers

M2R fluorescence-based biosensor panel and mixed quinoline-pyridine aromatic oligoamide helical foldamers address a similar problem space.

Shared frame: same top-level item type; shared mechanisms: conformational_uncaging; same primary input modality: chemical

Compared with UNC10245092

M2R fluorescence-based biosensor panel and UNC10245092 address a similar problem space.

Shared frame: same top-level item type; shared mechanisms: conformational_uncaging; same primary input modality: chemical

Relative tradeoffs: appears more independently replicated; looks easier to implement in practice.

Ranked Citations

  1. 1.
    StructuralSource 1MED2026Claim 1Claim 2Claim 3

    Extracted from this source document.