mtCLIC is up-regulated and maintains a mitochondrial membrane potential in mtDNA-depleted L929 cells.

Thierry Arnould, Ludovic Mercy, Andrée Houbion, Sébastien Vankoningsloo, Patricia Renard, Thierry Pascal, Noëlle Ninane, Catherine Demazy, Martine Raes

Research output: Contribution to journalArticlepeer-review


To explain why mitochondrial DNA (mtDNA)-depleted or rho0 cells still keep a mitochondrial membrane potential (Delta(psi)m) in the absence of respiration, several hypotheses have been proposed. The principal and well accepted one involves a reverse of action for ANT combined to F1-ATPase activity. However, the existence of other putative electrogenic channels has been speculated. Here, using mRNA differential display reverse transcriptase-polymerase chain reaction on L929 mtDNA-depleted cells, we identified mtCLIC as a differentially expressed gene in cells deprived from mitochondrial ATP production. Mitochondrial chloride intracellular channel (mtCLIC), a member of a recently discovered and expanding family of chloride intracellular channels, is up-regulated in mtDNA-depleted and rho0 cells. We showed that its expression is dependent on CREB and p53 and is sensitive to calcium and tumor necrosis factor alpha. Interestingly, up- or down-regulation of mtCLIC protein expression changes Delta(psi)m whereas the chloride channel inhibitor NPPB reduces the Delta(psi)m in mtDNA-depleted L929 cells, measured with the fluorescent probe rhodamine 123. Finally, we demonstrated that purified mitochondria from mtDNA-depleted cells incorporate, in a NPPB-sensitive manner, more 36chloride than parental mitochondria. These findings suggest that mtCLIC could be involved in mitochondrial membrane potential generation in mtDNA-depleted cells, a feature required to prevent apoptosis and to drive continuous protein import into mitochondria.

Original languageEnglish
Pages (from-to)2145-2147
Number of pages3
JournalThe FASEB journal : official publication of the Federation of American Societies for Experimental Biology
Issue number14
Publication statusPublished - 2003


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