Breakdown Prevention

Replacing weathered planks on a boat might keep you afloat, but if an over-zealous skivvy starts ripping up planks with abandon, the ship’ll sink before repairs can be made. Osteoclasts are the body’s enthusiastic dismantlers, breaking down bone to enable reinforcements when needed. New research has identified the captain that keeps these vigorous workers in check: a protein called moesin. Individual osteoclasts fuse together via tunnel-like nanotubes (pictured, a bridge stretching between cells) to form large, powerful cells capable of breaking down bone, and moesin regulates this by controlling how tightly the cytoskeleton (the cell's inner protein scaffolding) is attached to the cell membrane. Without it, the team found that cell membranes were more flexible, cells fused together more easily, and created larger zones of contact with bone. Moesin prevents osteoclasts from becoming too big, too fused, and too destructive, maintaining healthy bone balance and perhaps presenting a new therapeutic target in diseases like osteoporosis.

Written by Anthony Lewis

Anthony Lewis

Writer

Ant was the web editor in the early days of BPoD, and has since worked with the UK’s top science organisations as a writer and multimedia producer. He now splits his time between freelance work and managing multimedia at The Lancet.

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• Image from work by Ophélie Dufrançais and colleagues
• Institut de Pharmacologie et Biologie Structurale (IPBS), Université de Toulouse, Centre National de la Recherche Scientifique, Université Toulouse III - Paul Sabatier (UT3), Toulouse, France
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Journal of Cell Biology, October 2025