Ca2+ Sensors with Tuned Affinity for ER Monitoring
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Solution Overview
Problem
Current Ca2+ sensors lack specificity and sensitivity for accurately measuring intracellular Ca2+ concentrations in the endoplasmic reticulum, often perturbing the cellular environment and having limited affinity and dynamic range, making it difficult to assess changes in [Ca2+]ER effectively.
Innovation Solution
Development of analyte sensors with a molecular recognition motif integrated into an optically-active fluorescent host protein, which produces a detectable change upon Ca2+ interaction, allowing for precise measurement of Ca2+ levels with enhanced stability and sensitivity, including specific localization to intracellular compartments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If GFP-based Ca2+ sensors are used, then fluorescence detection is achieved, but the sensors perturb the cellular environment and have limited affinity and dynamic range
Solution Approach 1:
The patent applies local quality by creating compartment-specific Ca2+ sensors with different affinity ranges tailored to specific cellular locations. The sensor family includes variants with Kd values optimized for different compartments (e.g., higher affinity for ER, lower affinity for cytosol), allowing each sensor to measure Ca2+ in its target compartment without perturbing other cellular environments.
Solution Approach 2:
The patent employs parameter changes by systematically varying the affinity parameters of Ca2+ sensors through molecular design. Different sensor variants have been engineered with specific Kd values (e.g., 100 nM, 1 μM, 10 μM) to match the Ca2+ concentration ranges of different cellular compartments, thereby improving measurement precision while minimizing cellular perturbation.
2Measurement precision
If high affinity Ca2+ sensors are used, then detection sensitivity is improved, but the dynamic range is limited
Solution Approach 1:
The patent achieves universality by developing a universal sensor family that can measure Ca2+ across multiple concentration ranges and cellular compartments. The standardized sensor design with varying affinities allows a single platform to serve multiple functions: measuring cytosolic Ca2+ (low affinity sensors), ER Ca2+ (high affinity sensors), and tracking Ca2+ transients (various affinity sensors), thereby providing both high sensitivity and broad dynamic range.
3Measurement precision
If invasive methods are used to eliminate fluorescence background, then measurement accuracy improves, but cellular perturbation increases
Solution Approach 1:
The patent applies the taking out principle by extracting the fluorescence background problem through compartment-specific sensor design. By localizing sensors to specific compartments (e.g., ER-targeted sensors), the cytosolic fluorescence background is effectively removed or minimized, allowing accurate measurement without requiring invasive clearance methods that would damage cells.
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
These sensors provide accurate and minimally invasive means to monitor Ca2+ activity in real-time, overcoming limitations of existing sensors by offering improved affinity and reduced perturbation of cellular processes, enabling precise characterization of Ca2+ dynamics in living cells.
Implementation Method 1
an optically-active fluorescent host protein in which the molecular recognition motif is operatively linked to or integrated therein, wherein the interaction of the analyte to the molecular recognition motif produces a detectable change
Data Source
AI summary
Embodiments of the present disclosure provide methods for analyte sensors including methods for producing and using the analyte sensors, methods of detecting and/or measuring analyte activity, methods for characterizing analyte cellular activity, methods of detecting pH change in a system, method of controlling the concentration of an analyte in a system, fusion proteins, polynucleotides, and vectors corresponding to the analyte sensors, kits, and the like.