Double Brilliance Beta-Arrestin Biosensor for GPCR Monitoring
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Solution Overview
Problem
Current methods for monitoring receptor activation, particularly for G protein-coupled receptors, are limited by the need for modified receptor constructs and lack sensitivity, adaptability for large-scale screening, and the ability to provide quantitative results without expressing multiple recombinant constructs.
Innovation Solution
A novel intramolecular bioluminescence resonance energy transfer (BRET)-based biosensor using a β-arr molecule sandwiched between Renilla luciferase and yellow fluorescent protein (Luc-β-arr-YFP) to monitor conformational changes in β-arrestin upon agonist stimulation, allowing for sensitive and quantitative assessment of receptor activation without modifying the receptors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If modified receptor constructs are used to monitor receptor activation, then measurement capability is improved, but device complexity and ease of operation deteriorate due to requiring multiple recombinant constructs
Solution Approach 1:
The invention extracts the monitoring function from the receptor itself and places it in the β-arrestin biosensor. By fusing luciferase to the N-terminus and YFP to the C-terminus of β-arrestin, the sensor can monitor receptor activation through conformational changes in β-arrestin without requiring modification of the receptor protein. This separates the detection mechanism from the target molecule, resolving the contradiction between measurement capability and system complexity.
Solution Approach 2:
β-Arrestin serves as an intermediary molecule that translates receptor activation into a detectable optical signal. When the receptor is activated, it recruits β-arrestin, inducing conformational changes that alter the BRET signal between luciferase and YFP. This intermediary approach allows indirect monitoring of receptor activation without direct modification of the receptor, simplifying the overall system while maintaining measurement precision.
2Adaptability or versatility
If conventional BRET assays are used to assess β-arrestin recruitment, then adaptability for screening is improved, but measurement precision deteriorates due to inability to detect conformational changes
Solution Approach 1:
The invention merges two functions into a single β-arrestin biosensor: (1) recruitment to activated receptors and (2) conformational change detection. The dual fusion construct (luciferase-β-arrestin-YFP) simultaneously performs both functions, allowing the assay to monitor both the presence and activation state of β-arrestin. This merging enables the detection of conformational changes while maintaining the adaptability of BRET-based screening assays.
Solution Approach 2:
The invention utilizes color/energy transfer changes in the BRET system to detect conformational changes. The energy transfer efficiency between luciferase (donor) and YFP (acceptor) changes based on the conformational state of β-arrestin, providing a readout that reflects both recruitment and activation. This optical property change allows precise measurement of conformational dynamics while maintaining screening compatibility.
3Measurement precision
If intramolecular BRET biosensor is implemented, then sensitivity is improved, but device complexity increases due to dual fusion construct
Solution Approach 1:
The β-arrestin biosensor is self-regulating in that its own conformational changes upon receptor binding directly modulate the BRET signal. The intramolecular arrangement means that when β-arrestin undergoes conformational changes to bind the activated receptor, the relative positions of luciferase and YFP automatically change, altering energy transfer efficiency. This self-service mechanism enhances sensitivity without requiring external complex control systems, as the sensor uses its own structural dynamics for detection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the detection of agonist-induced conformational rearrangements in β-arrestin, providing a general tool for monitoring GPCR activity and other classes of receptors, suitable for high-throughput screening with improved sensitivity and adaptability, and the ability to detect inverse agonist effects.
Implementation Method 1
A novel intramolecular bioluminescence resonance energy transfer (BRET)-based biosensor using a β-arr molecule sandwiched between Renilla luciferase and yellow fluorescent protein (Luc-β-arr-YFP) to monitor conformational changes in β-arrestin upon agonist stimulation
Data Source
AI summary
An intramolecular bioluminescence resonance energy transfer (BRET), biosensor for monitoring receptor activity and signalling cascades is disclosed. The “double-brilliance” biosensor sandwiches β-arrestin (β-arr) between Renilla luciferase (Luc) and the yellow fluorescent protein (YFP). β-arr associates with G-protein coupled receptors GPCR following receptor activation, bringing Luc and YPF into close proximity that favours energy transfer. In addition to providing new insights into the agonist-induced conformational rearrangements of β-arr in living cells, the double-brilliance β-arr offers a universal biosensor for GPCR activation, allowing the study of native receptors in large-scale screening analysis. The activity of other signalling molecules known to interact with β arrestin could also be monitored by double brilliance β arr.