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Microtubules regulate local Ca2+ spiking in secretory epithelial cells
K E Fogarty1, J F Kidd, A Turner
1Department of Pharmacology, Cambridge University, Cambridge CB2 1QJ, United Kingdom.
The Journal of Biological Chemistry
|May 10, 2000
Summary
Microtubules are crucial for maintaining calcium (Ca2+) spikes in pancreatic cells by positioning the endoplasmic reticulum. Disrupting microtubules with nocodazole blocks these essential Ca2+ signals.
Area of Science:
- Cell Biology
- Physiology
Background:
- The cytoskeleton plays a role in calcium signaling.
- Calcium (Ca2+) release is critical for various cellular functions in epithelial cells.
Purpose of the Study:
- To investigate the role of the cytoskeleton, specifically microtubules, in regulating localized Ca2+ release in pancreatic acinar cells.
Main Methods:
- Whole-cell patch-clamp recording to measure Ca2+-dependent Cl- currents.
- Application of cytoskeleton-disrupting agents (cytochalasin B, nocodazole, colchicine) and stabilizers (taxol).
- 2-photon excitation microscopy to visualize endoplasmic reticulum localization.
Main Results:
- Nocodazole dose-dependently inhibited Ca2+ spike frequency and amplitude, leading to blockade.
- Colchicine also inhibited spiking, while inactive analogues had no effect.
- Microtubule disruption led to the loss of endoplasmic reticulum in the secretory pole region.
- The Ca2+ signaling apparatus remained functional, as evidenced by responses to carbachol.
Conclusions:
- Microtubules are essential for maintaining localized Ca2+ spikes in pancreatic acinar cells.
- This maintenance is, at least partly, due to the role of microtubules in positioning the endoplasmic reticulum.