MOTS-c and mitochondrial peptides: a second genome

Two sets of hereditary material in one cell

Almost all of our DNA sits in the cell nucleus. But the mitochondria, the cell's small power plants, have their own little piece of DNA. For a long time that counted as a leftover with limited function.

That picture is shifting. Researchers found that this mitochondrial DNA also codes for short peptides. MOTS-c is one of them.

The discovery of mitochondrial peptides

The research group around Pinchas Cohen and Changhan Lee described these molecules. First humanin, later MOTS-c. The name stands for Mitochondrial Open reading frame of the Twelve S rRNA type-c.

The finding mattered in principle. It showed that the mitochondrion does more than supply energy: it also sends signals to the rest of the cell.

What MOTS-c is

MOTS-c is a small peptide of sixteen amino acids. Studies describe it as a signalling molecule that touches metabolism. Under stress it moves in models toward the cell nucleus and influences gene activity there.

Metabolic signals in research

Many studies link MOTS-c to a central energy sensor of the cell, called AMPK. This sensor watches the energy balance.

• Glucose use: measurements of sugar uptake in muscle models.
• Stress response: how cells react to a shortage of energy.
• Gene activity: which genes switch on or off under stress.

The link with ageing

MOTS-c belongs in mitochondrial research, partly because measured levels in models appear to differ between young and older organisms. Researchers study whether mitochondrial peptides play a part in how cells age.

This is exploratory work. The question is open and active.

A sober caveat

Nearly all of this knowledge comes from cells and animal models. MOTS-c is a fascinating research subject, not a finished application. That distinction belongs to an honest reading.