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Updated: Dec 30, 2025
Imaging the Neutrophil Phagosome and Cytoplasm Using a Ratiometric pH Indicator
Published on: April 5, 2017
Imaging stressed organelles via sugar-conjugated color-switchable pH sensors
Enkang Zhang1, Siyu Wang, Xinhui Su
1Department of Chemical Biology, College of Chemistry and Chemical Engineering, State Key Laboratory for Physical Chemistry of Solid Surfaces, the Key Laboratory for Chemical Biology of Fujian Province, The MOE Key Laboratory of Spectrochemical Analysis & Instrumentation, and State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, 361005, China. shoufa@xmu.edu.cn.
Abstract:
Stressed organelles are often challenging to image with canonical organelle probes owing to their propensity to dissipate from stressed organelles. We herein report the imaging of stressed lysosomes with color-switchable glyco-probes that contain an entity of mannose-6-carboxylate or sialic acid for targeting to and long-term retention in stressed lysosomes, and a diad of fluorescein/rhodamine-X-lactam exhibiting dramatic red-to-green fluorescence shift upon pH elevation. Relative to acidotropic dyes prone to dissipate from pH-elevated lysosomes, both glyco-probes are stably trapped in lysosomes without resorting to lysosomal acidity. Importantly, these probes are red emissive in acidic lysosomes (pH 4.5-5.8), but switched to green fluorescence in lysosomes of pH 6.0-7.4, allowing dual color discrimination of lysosomal pH alterations in cell starvation. These results support the use of sugar-armed sensors to investigate stressed lysosomes in biology and disease.
