A scrape (arrow) lets in a red dye and brings lysosomes (green) to the surface.
Andrews/Elsevier
Incessant wear and tear on plasma membranes is a fact of cell life, so it's not surprising that cells know how to fix the resulting damage quickly—often within a few seconds. Norma Andrews and her colleagues (Yale University School of Medicine, New Haven, CT) have just revealed how plasma membrane repair works. In the process they have demonstrated a new function for the cell's decomposition specialists, the lysosomes.
Others have observed that membrane repair and calcium-regulated exocytosis often occur at the same time, with unidentified vesicles flocking to the site of injury. Andrews and her colleagues decided to test whether those vesicles were lysosomes, and if they were responsible for membrane repair. Via several methods—for example, using monoclonal antibodies against a major lysosomal glycoprotein—they conclude that blocking lysosomes' ability...
