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Imaging Local Ca2+ Signals in Cultured Mammalian Cells
Published on: March 3, 2015
Seeing is believing! Imaging Ca2+-signalling events in living cells
1Centre for Vision and Vascular Sciences, Queen's University of Belfast, Institute of Clinical Sciences, Grosvenor Road, Royal Victoria Hospital, Belfast BT12 6BA, UK. g.mcgeown@qub.ac.uk
Experimental Physiology
|August 11, 2010
Summary
Calcium ions (Ca2+) are vital cell signals regulating muscle contraction and other cellular processes. Recent imaging reveals detailed subcellular Ca2+ activity, like sparks, influencing muscle function and requiring updated signaling models.
Area of Science:
- Physiology
- Cell Biology
- Biochemistry
Background:
- Extracellular calcium (Ca2+) is essential for muscle contraction, with its intracellular concentration ([Ca2+]i) increasing before contraction.
- Early studies used photoproteins like aequorin to link Ca2+ to muscle excitation-contraction coupling.
- The development of Ca2+ indicators revolutionized research, establishing Ca2+ as a ubiquitous cellular signal.
Discussion:
- High-speed imaging identified Ca2+ sparks, crucial for cardiac excitation-contraction coupling and having diverse roles in smooth muscle.
- Ca2+ sparks modulate global Ca2+ signaling through Ca2+-sensitive currents, influencing membrane potential and channel activity.
- Agonists can induce distinct Ca2+ signaling patterns, with whole-tissue tonic increases masking cellular-level phasic oscillations.
Key Insights:
- Ca2+ sparks are fundamental units of Ca2+ signaling in muscle.
- Ca2+ sparks exhibit both excitatory and inhibitory feedback mechanisms in smooth muscle.
- Cellular and subcellular Ca2+ dynamics reveal complexities beyond average concentration changes.
Outlook:
- Future research will likely employ genetically encoded Ca2+ indicators for organelle- and tissue-specific studies.
- Re-evaluation of Ca2+ signaling models is needed to incorporate detailed subcellular dynamics.
- Advanced imaging techniques will continue to uncover novel aspects of Ca2+ regulation in living cells.
