Scientists at Harvard Medical School in Boston recently published a study in Nature that utilized RNAi technology to identify a protein that is responsible for mitochondrial calcium absorption. The protein, dubbed MCU, was found by aligning the mitochondrial genome of humans, Trypanosomes and baker’s yeast which had been previously published in the MitoCarta mitochondrial genome database. By overlapping the mitochondrial protein profiles of these three organisms, the group could spotlight roughly 50 proteins out of the 1,000 that might be involved with calcium channeling. They found that one protein, which they dubbed MICU1, is essential for calcium uptake.
With MICU1 as their point of reference, they scoured those databases that measure whole genome RNA and protein expression, as well as an additional database containing genomic information for 500 species, and looked for proteins whose activity profile mirrored MICU1′s. A single anonymous protein with no known function stood out. The researchers named it MCU, short for “mitochondrial calcium uniporter.”
To confirm that MCU is central to mitochondria’s calcium absorption, the team collaborated with Alnylam Pharmaceuticals, a company that leverages a laboratory tool called RNAi in order to selectively knock out genes in both cells and live animals. Using one of the company’s platforms, the researchers deactivated MCU in the livers of mice. While the mice displayed no immediate reaction, the mitochondria in their liver tissue lost the capacity to absorb calcium.
Source: Harvard Medical School