Decoding of cytoplasmic Ca(2+) oscillations through the spatial signature drives gene expression

Area of Science:

• Cellular Biology
• Molecular Signaling
• Immunology

Background:

• Cytoplasmic Ca2+ oscillations are fundamental cellular signals.
• These oscillations are thought to encode information via amplitude and frequency.
• Their precise role in activating specific cellular responses, like gene expression, remains debated.

Purpose of the Study:

• To investigate the role of spatial Ca2+ gradients within oscillations in triggering cellular responses.
• To determine whether global Ca2+ oscillations or local Ca2+ influx is critical for gene expression.
• To elucidate the mechanism by which Ca2+ signals activate gene expression in mast cells.

Main Methods:

• Inducing Ca2+ oscillations in mast cells using varying agonist concentrations.
• Manipulating external Ca2+ levels and plasmalemmal Ca2+ extrusion.
• Employing cytoplasmic Ca2+ buffering to assess its impact on oscillations and gene activation.
• Utilizing store-operated CRAC channels for Ca2+ entry.

Main Results:

• Ca2+ oscillations were similar with or without external Ca2+ when extrusion was blocked.
• Gene expression was only triggered by oscillations accompanied by Ca2+ entry via CRAC channels.
• Increased cytoplasmic Ca2+ buffering abolished oscillations but not gene activation.
• Local Ca2+ influx, not global oscillations, was identified as the driver of gene expression.

Conclusions:

• Spatial Ca2+ gradients within oscillations are crucial for activating specific cellular pathways.
• Local Ca2+ influx through CRAC channels, rather than global oscillations, dictates gene expression.
• Ca2+ oscillations may function to activate CRAC channels, generating localized signals for gene activation.