Scientists have solved a long-standing puzzle about the brain: how do cells know how much myelin to wrap around each nerve fibre? The answer, found by Upstate Medical University researchers, is a protein called Piezo1 that acts as a molecular ruler.

Oligodendrocytes — the cells that make myelin — use Piezo1 to sense the diameter of the nerve fibres they are wrapping. Thicker fibres get longer myelin segments; thinner ones get shorter ones. This scaling tunes the speed of nerve signals across the brain.

The study, led by recent PhD graduate Amanda R. Young in the Bechler lab and published in PLOS Biology, found Piezo1 is most active during the early stages of myelination, when sheaths are being built and extended.

Because myelin controls signal speed, the discovery could guide future research into diseases like multiple sclerosis, where myelin is destroyed. Understanding the ruler may one day help scientists rebuild the insulation correctly.

Sources: medicalxpress.com; neurosciencenews.com.