Fluorescence detection of NO in subcellular organelles of HeLa and MCF-7 cells.

<p>Targeted localization of HTDAF-2 by conjugation to HaloTag proteins in living HeLa cells. Images present HeLa cells expressing HaloTag in the cytosol/nucleus (A), nucleus (B), membrane (C), and mitochondria (D), with the red fluorescent protein mCherry fused with the same signal peptides. Scale bar = 10 μm. (E) Direct in-gel fluorescence of control (1), nucleus-HaloTag (2), plasma membrane-HaloTag (3), cytosol-HaloTag (4), and mitochondria-HaloTag (5) in HeLa cells labeled with 5 μM HTDAF-2DA. (F) The fluorescence responses of 5 μM HTDAF-2DA targeted in the plasma membrane to various concentrations of NO donor (DEA NONOate) in HeLa cells. (G and H) Kinetics of fluorescence response of 5 μM HTDAF-2DA in different subcellular compartments of HeLa (G) and MCF-7 (H) cells upon the addition of NO donor (DEA NONOate). Error bars represent SD.