Zinc is a novel intracellular second messenger

Zinc is an essential trace element required for enzymatic activity and for maintaining the conformation of many transcription factors; thus, zinc homeostasis is tightly regulated. Although zinc affects several signaling molecules and may act as a neurotransmitter, it remains unknown whether zinc acts as an intracellular second messenger capable of transducing extracellular stimuli into intracellular signaling events. In this study, we report that the cross-linking of the high affinity immunoglobin E receptor (Fcɛ receptor I [FcɛRI]) induced a release of free zinc from the perinuclear area, including the endoplasmic reticulum in mast cells, a phenomenon we call the zinc wave. The zinc wave was dependent on calcium influx and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase activation. The results suggest that the zinc wave is involved in intracellular signaling events, at least in part by modulating the duration and strength of FcɛRI-mediated signaling. Collectively, our findings indicate that zinc is a novel intracellular second messenger

Slitflow: A Python framework for single-molecule dynamics and localization analysis

Single-molecule imaging is a promising method for direct quantification of the dynamics and distribution of biomolecules in living cells. Although numerous methods have been developed to gain biological insights into molecular behavior, the high diversity of microscopes and single-molecule dynamics can result in incomplete reproducibility of analyses. Here, we present Slitflow, an open-source framework for a single-molecule analysis workflow that includes image processing, dynamics analysis, and figure creation. We demonstrated the integrity and flexibility of the workflow using (1) a cherry-picked tracking method combining popular tools and (2) various state-of-the-art analyses in a single pipeline. The software accommodates a large variety of data and methods, paving the way for integrative analyses