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Visualization of Endoplasmic Reticulum Subdomains in Cultured Cells
Published on: February 18, 2014
Sensitive imaging of Endoplasmic reticulum (ER) autophagy with an acidity-reporting ER-Tracker
Yilong Shi1, Xiaoxue Zou1, Xianghui Zheng2
1State 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 Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China.
Abstract:
Macroautophagic/autophagic turnover of endoplasmic reticulum (reticulophagy) is critical for cell health. Herein we reported a sensitive fluorescence-on imaging of reticulophagy using a small molecule probe (ER-proRed) comprised of green-emissive fluorinated rhodol for ER targeting and nonfluorescent rhodamine-lactam prone to lysosome-triggered red fluorescence. Partitioned in ER to exhibit green fluorescence, ER-proRed gives intense red fluorescence upon co-delivery with ER into acidic lysosomes. Serving as the signal of reticulophagy, the turning on of red fluorescence enables discernment of reticulophagy induced by starvation, varied levels of reticulophagic receptors, and chemical agents such as etoposide and sodium butyrate. These results show ER probes optically activatable in lysosomes, such as ER-proRed, offer a sensitive and simplified tool for studying reticulophagy in biology and diseases.Abbreviations: Baf-A1, bafilomycin A1; CCCP, carbonyl cyanide m-chlorophenyl hydrazone; CQ, chloroquine diphosphate; ER, endoplasmic reticulum; FHR, fluorinated hydrophobic rhodol; GFP, green fluorescent protein; Reticulophagy, selective autophagy of ER; RFP, red fluorescent protein; ROX, X-rhodamine; UPR, unfolded protein response.

