Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8299023 | Biochimica et Biophysica Acta (BBA) - Bioenergetics | 2010 | 8 Pages |
Abstract
The mitochondrial intermediate-conductance Ca2+-activated K+ channel mtKCa3.1 has recently been discovered in the HCT116 colon tumor-derived cell line, which expresses relatively high levels of this protein also in the plasma membrane. Electrophysiological recordings revealed that the channel can exhibit different conductance states and kinetic modes, which we tentatively ascribe to post-translational modifications. To verify whether the localization of this channel in mitochondria might be a peculiarity of these cells or a more widespread feature we have checked for the presence of mtKCa3.1 in a few other cell lines using biochemical and electrophysiological approaches. It turned out to be present at least in some of the cells investigated. Functional assays explored the possibility that mtKCa3.1 might be involved in cell proliferation or play a role similar to that of the Shaker-type KV1.3 channel in lymphocytes, which interacts with outer mitochondrial membrane-inserted Bax thereby promoting apoptosis (Szabò, I. et al., Proc. Natl. Acad Sci. USA 105 (2008) 14861-14866). A specific KCa3.1 inhibitor however did not have any detectable effect on cell proliferation or death.
Keywords
PBSPKCMPTPPMCApKaKATPHBSSRLMMAMTRAM-34HCT116MgTxMEFTESOMMsarcoplasmic/endoplasmic reticulum Ca2+-ATPaseHEPESGSTDMEMMDRTASK-33-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide4-(2-hydroxyethyl)-1-piperazineethanesulfonic acidBKCaDulbecco's modified Eagle MediumI/RIKCaMTTN-tris(hydroxymethyl)methyl-2-aminoethanesulfonic acidPACsROSmitochondrial permeability transition poreimmCSAischemia/reperfusionRiskinner mitochondrial membraneHank's balanced saline solutionendoplasmatic reticulumcyclosporin AShKMitochondria-associated membranesouter mitochondrial membranePlasma membranePlasma membrane Ca2+-ATPasePhosphate buffered salineSERCAmargatoxinMultiple drug resistancemouse embryonic fibroblastRat liver mitochondriaprotein kinase AProtein kinase CATP-sensitive K+ channelclotrimazoleglutathione-S-transferaseReactive oxygen species
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Authors
Nicola Sassi, Umberto De Marchi, Bernard Fioretti, Lucia Biasutto, Erich Gulbins, Fabio Franciolini, Ildikò Szabò, Mario Zoratti,