Stretch your skin and it springs back to shape – a property also possessed by the lining of your throat, inner ear, blood vessels and many other body parts. This springy tension is due to each surface cell having a tiny belt, formed by the proteins myosin and actin, wrapped around it, rather like an elastic band. Scientists have discovered that these belts are interlinked so that their stretching and squeezing actions spread like waves through the millions of cells, controlling the shape and movement of the surface (epithelial) tissue. Pictured (bottom) is a normal arrangement of surface cells of a rat’s intestine, with actin stained red and cell boundaries green. When myosin is chemically deactivated, the protein belts stop working, causing the cells to drift apart (top).
Written by Mick Warwicker
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