Interrogating Intracellular Zinc Chemistry with a Long Stokes Shift Zinc Probe ZincBY-4.
J Am Chem Soc. 2019 Sep 24;:
Authors: Garwin SA, Kelley MSJ, Sue AC, Que EL, Schatz GC, Woodruff TK, O'Halloran TV
Fluctuations in zinc content and subcellular localization have been shown to play key roles in regulating cell cycle progression; however, a deep mechanistic understanding requires the determination of when, where, and how labile zinc pools are concentrated into or released from stores. Labile zinc ions can be difficult to detect with probes that require hydrolysis of toxic protecting groups or application at high concentrations that negatively impact cell function. We described a BODIPY-based zinc probe, ZincBY-1, that can be used at working concentrations that are 20-200-fold lower than concentrations employed with other probes. To better understand how this probe can reveal zinc pools at such low concentrations, we modulated the photophysical properties via changes at the 5-position of the BODIPY core. One of these, ZincBY-4, exhibits an order of magnitude higher affinity for zinc, an 8-fold increase in brightness in response to zinc, and a 100 nm stokes shift within cells. The larger stokes shift of ZincBY-4 presents a unique opportunity for simultaneous imaging with GFP or fluorescein sensors upon single excitation. Finally, by creating a proxy for the cellular environment in spectrometer experiments, we show that the ZincBY series are highly effective at 50 nM because they can pass membranes and accumulate in regions of high zinc concentration within a cell. These features of the ZincBY probe class have widespread applications in imaging and for understanding the regulatory roles of zinc fluxes in live cells.
PMID: 31550140 [PubMed - as supplied by publisher]