Bednarczyk P, Dołowy K, Szewczyk A. Matrix Mg2+ regulates mitochondrial ATP-dependent potassium channel from heart.
FEBS Lett 2005;
579:1625-32. [PMID:
15757652 DOI:
10.1016/j.febslet.2005.01.077]
[Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2004] [Revised: 01/11/2005] [Accepted: 01/31/2005] [Indexed: 10/25/2022]
Abstract
Mitochondrial ATP-regulated potassium (mitoKATP) channels play an important role in cardioprotection. Single channel activity was measured after reconstitution of inner mitochondrial membranes from bovine myocardium into a planar lipid bilayer. After incorporation, the potassium channel was recorded with a mean conductance of 103+/-9 pS. The channel activity was inhibited by ATP/Mg and activated by GDP. Magnesium ions alone affected, in a dose dependent manner, both the channel conductance and the open probability. Magnesium ions regulated the mitoKATP channel only when added to the trans compartment. We conclude that Mg2+ regulates the cardiac mitoKATP channel from the matrix site by affecting both the channel conductance and gating.
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