Magnesium permeation through mechanosensitive channels: single-current measurements
Alexander V Staruschenko1, Anastasiya V Sudarikova, Yuri A Negulyaev
1Institute of Cytology, Russian Academy of Sciences, St Petersburg, Russia.
Cell Research
|July 28, 2006
Summary
Mechanosensitive channels allow magnesium ion (Mg2+) influx into mammalian cells. These stretch-activated channels demonstrate Mg2+ permeability, crucial for regulating cell activity.
Area of Science:
- Cellular Biology
- Ion Transport Mechanisms
- Biophysics
Background:
- Intracellular free magnesium ([Mg2+]i) is vital for eukaryotic cell regulation.
- Mechanisms of Mg2+ influx in mammalian cells remain largely unknown.
Purpose of the Study:
- To investigate the role of mechanosensitive (MS) cationic channels in Mg2+ transport.
- To determine Mg2+ permeability through MS channels in mammalian cells.
Main Methods:
- Single-channel current recordings from cell-attached and inside-out patches on K562 leukaemia cells.
- Electrophysiological measurements of Mg2+ influx at varying extracellular MgCl2 concentrations.
- Analysis of unitary conductance and saturation effects of Mg2+ permeation.
Main Results:
- Mechanosensitive channels are permeable to Mg2+ ions at physiological concentrations.
- Mg2+ influx through MS channels showed significant saturation at higher concentrations.
- Unitary conductance for Mg2+ influx was approximately 5 pS at 2 mM Mg2+ and around 6.4-6.8 pS at higher concentrations.
Conclusions:
- Mechanosensitive channels facilitate Mg2+ influx in leukaemia cells.
- Single-current measurements provide evidence for Mg2+ permeation through stretch-activated channels.
- These findings highlight a novel pathway for Mg2+ transport in mammalian cells.
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