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Mitochondrial participation in the intracellular Ca2+ network
D F Babcock1, J Herrington, P C Goodwin
1Department of Physiology & Biophysics, University of Washington, Seattle 98195-7290, USA.
The Journal of Cell Biology
|February 24, 1997
Summary
Mitochondria actively regulate cellular calcium (Ca2+) signaling by rapidly taking up and releasing Ca2+. This mitochondrial Ca2+ buffering influences cytosolic Ca2+ levels, impacting cellular responses.
Area of Science:
- Cellular Physiology
- Mitochondrial Biology
- Calcium Signaling
Background:
- Mitochondrial calcium (Ca2+) uptake and release influence cytosolic Ca2+ concentrations (Cac).
- The role of mitochondria in dynamic Ca2+ signaling has garnered renewed scientific interest.
Purpose of the Study:
- To investigate the role of mitochondrial Ca2+ uptake and extrusion in modulating cytosolic Ca2+.
- To quantify mitochondrial Ca2+ levels (Cam) and their relationship with Cac in real-time.
Main Methods:
- Whole-cell and perforated patch clamp techniques on rat chromaffin cells.
- Rapid local perfusion for introducing probes and inhibitors.
- Imaging and single-cell photometry using the probe rhod-2 for Cam quantification.
Main Results:
- Rapid Cac recovery requires mitochondrial Ca2+ uniporter and mitochondrial energization.
- Mitochondrial Ca2+ sequestration is rapid and high-capacity, limiting Cac rise and promoting decay.
- Mitochondrial Ca2+ export prolongs Cac recovery; inhibiting the Na+/Ca2+ exchanger hastens it.
Conclusions:
- Mitochondria are dynamic regulators of cellular Ca2+ signaling.
- Their ability to rapidly sequester and release Ca2+ is crucial for Ca2+ homeostasis.