@article {70093,
	title = {iGABASnFR2: Improved genetically encoded protein sensors of GABA},
	journal = {eLife},
	year = {2025},
	month = {2025 Sept 03},
	abstract = {<p>Monitoring GABAergic inhibition in the nervous system has been enabled by development of an intensiometric molecular sensor that directly detects GABA. However, the first generation iGABASnFR exhibits low signal-to-noise and suboptimal kinetics, making in vivo experiments challenging. To improve sensor performance, we targeted several sites in the protein for near-saturation mutagenesis and evaluated the resulting sensor variants in a high throughput screening system using evoked synaptic release in primary cultured neurons. This identified a sensor variant, iGABASnFR2, with 4.2-fold improved sensitivity and 20\% faster kinetics, and binding affinity that remained in a range sensitive to changes in GABA concentration at synapses. We also identified sensors with an inverted response, decreasing fluorescence intensity upon GABA binding. We termed the best such negative-going sensor iGABASnFR2n, which can be used to corroborate observations with the positive-going sensor. These improvements yielded a qualitative enhancement of in vivo performance when compared directly to the original sensor. iGABASnFR2 enabled the first measurements of direction-selective GABA release in the retina. In vivo imaging in somatosensory cortex revealed that iGABASnFR2 can report volume-transmitted GABA release following whisker stimulation. Overall, the improved sensitivity and kinetics of iGABASnFR2 make it a more effective tool for imaging GABAergic transmission in intact neural circuits.</p>
},
	doi = {10.7554/elife.108319.1},
	url = {http://dx.doi.org/10.7554/eLife.108319.1},
	author = {Kolb, Ilya and Hasseman, Jeremy P and Matsumoto, Akihiro and Jensen, Thomas P and Kopach, Olga and Arthur, Benjamin J and Zhang, Yan and Tsang, Arthur and Reep, Daniel and Tsegaye, Getahun and Zheng, Jihong and Patel, Ronak H and Looger, Loren L and Marvin, Jonathan S and Korff, Wyatt L and Rusakov, Dmitri A and Yonehara, Keisuke and Turner, Glenn C}
}
@article {70182,
	title = {iGlucoSnFR2: A genetically encoded fluorescent sensor for measuring intracellular or extracellular glucose in vivo in mouse brain.},
	journal = {Sci Adv},
	volume = {11},
	year = {2025},
	month = {2025 Nov 14},
	pages = {eadz3889},
	abstract = {<p>Continuous glucose monitors have proven invaluable for monitoring blood glucose levels for diabetics, but they are of limited use for observing glucose dynamics at the cellular (or subcellular) level. We have developed a second generation, genetically encoded intensity-based glucose sensing fluorescent reporter (iGlucoSnFR2). We show that when it is targeted to the cytosol, it reports intracellular glucose consumption and gluconeogenesis in cell culture, along with efflux from the endoplasmic reticulum. It outperforms the original iGlucoSnFR in vivo when observed by fiber photometry in mouse brain and reports transient increase in glucose concentration when stimulated by noradrenaline or electrical stimulation. Last, we demonstrate that membrane localized iGlucoSnFR2 can be calibrated in vivo to indicate absolute changes in extracellular glucose concentration in awake mice. We anticipate iGlucoSnFR2 facilitating previously unobservable measurements of glucose dynamics with high spatial and temporal resolution in living mammals and other experimental organisms.</p>
},
	issn = {2375-2548},
	doi = {10.1126/sciadv.adz3889},
	url = {https://doi.org/10.1126/sciadv.adz3889},
	author = {Marvin, Jonathan S and M{\"a}chler, Philipp and Meng, Chengbo and Ates, Tayfun and Patel, Ronak H and Adhikari, Raghabendra and Makurath, Monika A and Ku, Zaneta and Feliciano, Daniel and Atasoy, Deniz and Cui, Guohong and Kleinfeld, David and Brown, Timothy A}
}
