MitoBKCa is encoded by the Kcnma1 gene, and a splicing sequence defines its mitochondrial location

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Details

Original languageEnglish (US)
Pages (from-to)10836-10841
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume110
Issue number26
StatusPublished - Jun 25 2013
Peer-reviewedYes

Abstract

The large-conductance Ca2+- and voltage-activated K+ channel (BKCa, MaxiK), which is encoded by the Kcnma1 gene, is generally expressed at the plasma membrane of excitable and nonexcitable cells. However, in adult cardiomyocytes, a BKCa-like channel activity has been reported in the mitochondria but not at the plasma membrane. The putative opening of this channel with the BKCa agonist, NS1619, protects the heart from ischemic insult. However, the molecular origin of mitochondrial BKCa (mitoBKCa) is unknown because its linkage to Kcnma1 has been questioned on biochemical and molecular grounds. Here, we unequivocally demonstrate that the molecular correlate of mitoBKCa is the Kcnma1 gene, which produces a protein that migrates at ~140 kDa and arranges in clusters of ~50 nm in purified mitochondria. Physiological experiments further support the origin ofmitoBKCa as a Kcnma1 product because NS1619- mediated cardioprotection was absent in Kcnma1 knockout mice. Finally, BK Ca transcript analysis and expression in adult cardiomyocytes led to the discovery of a 50-aa C-terminal splice insert as essential for the mitochondrial targeting of mitoBKCa.

    Research areas

  • BK channel, KCa1.1, Splice variation

Citation formats

APA

Singh, H., Lu, R., Bopassa, J. C., Meredith, A. L., Stefani, E., & Toro, L. (2013). MitoBKCa is encoded by the Kcnma1 gene, and a splicing sequence defines its mitochondrial location. Proceedings of the National Academy of Sciences of the United States of America, 110(26), 10836-10841. https://doi.org/10.1073/pnas.1302028110

Harvard

Singh, H, Lu, R, Bopassa, JC, Meredith, AL, Stefani, E & Toro, L 2013, 'MitoBKCa is encoded by the Kcnma1 gene, and a splicing sequence defines its mitochondrial location', Proceedings of the National Academy of Sciences of the United States of America, vol. 110, no. 26, pp. 10836-10841. https://doi.org/10.1073/pnas.1302028110