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Fluorescent Calcium Imaging and Subsequent In Situ Hybridization for Neuronal Precursor Characterization in Xenopus laevis
Published on: February 18, 2020
'Trigger' events precede calcium puffs in Xenopus oocytes
Heather J Rose1, Sheila Dargan, Jianwei Shuai
1Department of Neurobiology and Behavior, University of California, Irvine, CA 92697, USA. heather@uci.edu
Biophysical Journal
|September 19, 2006
Summary
Researchers identified novel "trigger events" that initiate calcium puffs, fundamental units of cellular calcium signaling. These small calcium elevations, possibly from single IP3 receptor openings, precede larger puffs and offer insights into IP3 receptor clusters.
Area of Science:
- Cellular Biology
- Molecular Physiology
- Calcium Signaling
Background:
- Calcium ions (Ca2+) released from the endoplasmic reticulum via inositol 1,4,5-trisphosphate receptors/channels (IP3Rs) orchestrate complex cellular signaling.
- These signaling events form a hierarchy, from single-channel openings to local Ca2+ puffs and global calcium waves.
Purpose of the Study:
- To investigate the initial events preceding the formation of Ca2+ puffs.
- To characterize the properties and proposed mechanism of these initiating events.
Main Methods:
- High-resolution confocal linescan imaging.
- Utilized a sensitive Ca2+ indicator dye (fluo-4-dextran) for precise measurements.
Main Results:
- Identified and termed 'trigger events' – small, transient Ca2+ elevations preceding Ca2+ puffs.
- Trigger events, consistent with single IP3R opening, initiate puffs via Ca2+-induced Ca2+ release.
- Puffs are ~6x larger than triggers, suggesting multiple IP3Rs open simultaneously; trigger events are smaller and faster.
Conclusions:
- Trigger events are fundamental initiators of Ca2+ puffs, the building blocks of IP3-mediated Ca2+ signals.
- Understanding trigger events provides insights into the number and arrangement of IP3Rs within clusters.
- These findings are crucial for comprehending the fundamental mechanisms of cellular signaling.
