F-actin-based Ca signaling—a critical comparison with the current concept of Ca signaling
✍ Scribed by Klaus Lange; Joachim Gartzke
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 561 KB
- Volume
- 209
- Category
- Article
- ISSN
- 0021-9541
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✦ Synopsis
Abstract
A short comparative survey on the current idea of Ca signaling and the alternative concept of F‐actin‐based Ca signaling is given. The two hypotheses differ in one central aspect, the mechanism of Ca storage. The current theory rests on the assumption of Ca‐accumulating endoplasmic/sarcoplasmic reticulum‐derived vesicles equipped with an ATP‐dependent Ca pump and IP~3~‐ or ryanodine‐sensitive channel‐receptors for Ca‐release. The alternative hypothesis proceeds from the idea of Ca storage at the high‐affinity binding sites of actin filaments. Cellular sites of F‐actin‐based Ca storage are microvilli and the submembrane cytoskeleton. Several specific features of Ca signaling such as store‐channel coupling, quantal Ca release, spiking and oscillations, biphasic and “phasic” uptake kinetics, and Ca‐induced Ca release (CICR), which are not adequately described by the current concept, are inherent properties of the F‐actin system and its dynamic state of treadmilling. J. Cell. Physiol. 209: 270–287, 2006. © 2006 Wiley‐Liss, Inc.