Genome-wide RNAi screen identifies Letm1 as a mitochondrial Ca2+/H+ antiporter.


Dawei Jiang, Linlin Zhao, and David E Clapham. 2009. “Genome-wide RNAi screen identifies Letm1 as a mitochondrial Ca2+/H+ antiporter.” Science, 326, 5949, Pp. 144-7.
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Mitochondria are integral components of cellular calcium (Ca2+) signaling. Calcium stimulates mitochondrial adenosine 5'-triphosphate production, but can also initiate apoptosis. In turn, cytoplasmic Ca2+ concentrations are regulated by mitochondria. Although several transporter and ion-channel mechanisms have been measured in mitochondria, the molecules that govern Ca2+ movement across the inner mitochondrial membrane are unknown. We searched for genes that regulate mitochondrial Ca2+ and H+ concentrations using a genome-wide Drosophila RNA interference (RNAi) screen. The mammalian homolog of one Drosophila gene identified in the screen, Letm1, was found to specifically mediate coupled Ca2+/H+ exchange. RNAi knockdown, overexpression, and liposome reconstitution of the purified Letm1 protein demonstrate that Letm1 is a mitochondrial Ca2+/H+ antiporter.

Last updated on 08/23/2016