Early Endosomes Undergo Calcium‐Triggered Exocytosis and Enable Repair of Diffuse and Focal Plasma Membrane Injury (Adv. Sci. 33/2023)

Early Endosomes The graphic scenery depicts a cell, observed en‐face (from the side) being subjected to an onslaught of plasma‐membrane damaging agents. These agents include extracellular barrel‐shaped bacteria‐secreted pore‐forming toxins (silver purple‐lined barrels) that bind to and disrupt the targets cell's plasma membrane via the generation of protein lined pores, exposing the inside of the cell to the outside environment (hence the extracellular light shining through these pores). As an alternative form of injury, the cell membrane can be injured in a mechanical manner, in this case via pulsed laser ablation from a microscope system (red lasers). The authors' findings demonstrate that a specific and previously unrecognized “early endosome” population within the cell is rapidly mobilized to fuse with the injured membrane and this is required for successful repair across these different injury contexts. The early endosomes and their injury‐triggered fusion with the membrane are depicted by the dashing/motion‐blurred orange lipid vesicles, as they are actively rushing to fuse with the cell's injured plasma membrane to assist in repair. More details can be found in article number 2300245 by Daniel C. Bittel and Jyoti K. Jaiswal. [Image: see text]