PMID-19623246 Second and third generation voltage-sensitive fluorescent proteins for monitoring membrane potential.
- "A now broadly used approach to fluorescent biosensor engineering involves the molecular fusion of a GFP-based reporter protein to a second protein that undergoes conformational transitions in response to a physiological signal such as fluctuations in calcium or membrane potential"
- Fluorescent proteins are hard to target: "confocal microscopy analysis revealed a prominent intracellular expression for Flare (a Kv1.4 FlaSh variant), VSFP1 and SPARC with little, if any, fluorescence associated with the cell surface in both HEK293 cells and hippocampal eurons. "
- Experimentation lead to development of VSFP3.1 (voltage sensitive fluorescent protein #3.1), which features only CFP and no acceptor FP. The cyan signal has ~1ms kinetics, consistent with the voltage-sensing membrane protein Ci-VSP speed.
- Unclear about the of this sensor; the other sensors are FRET based, hence ratiometric:
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