Lines of Asymmetry

From a distance we look roughly symmetrical, but we’re not completely – our faces might look odd if they were. Many of our organs must develop asymmetrically to take on their correct shape or move into place. But where does this asymmetry come from? These human cells are growing on circular stages under a high-powered microscope. Tiny 'bones' of actin (highlighted in green) in their cytoskeletons develop chirality – that is, they twist in a particular direction. Researchers find a group of proteins which sway these actin patterns. When they block the activity of profilin 1, for example, the direction of the actin swirl changes from anticlockwise (top left) to clockwise (top right). This switch is reversible (bottom left) and doesn't happen when blocking a similar protein, profilin 2 (bottom right). With these roots of asymmetry discovered, researchers may now trace lines of asymmetry throughout our development.

Written by John Ankers

• Image adapted from work by Yee Han Tee and colleagues
• Mechanobiology Institute, National University of Singapore, Singapore
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Nature Communications, February 2023