Navigating the Plant Cell: The Function and Evolution of SOSEKI Polar Proteins

Samenvatting (Engelstalig)

Plants grow in organized patterns because their cells can sense directions—like up toward the shoot or down toward the root. This “sense of direction,” called polarity, depends on proteins that sit on specific sides of the cell and guide growth, division, and nutrient flow. This work focuses on a family of such proteins, called SOSEKIs, which are found in all land plants and have been conserved for over 450 million years. Using genetic tools, it shows that most SOSEKIs are not essential under normal conditions, but one SOSEKI is crucial for maintaining growth zones in plants. The research also uncovers how SOSEKIs find and attach to cell edges, using a small membrane-binding fragment, and reveals that this mechanism is ancient and shared across plant species. These findings provide new insights into how plants build complex bodies and highlight a universal system that positions proteins within cells.