Pinched off membrane

Cells slough off extra membrane by pinching it off into the extracellular space, say Dubreuil et al. on page 483. The discarded membrane can be released by either cilia or midbodies, with potentially distinct outcomes.

Membrane particles can be seen floating in the extracellular space of the developing neural tube. These particles are distinct from signaling exosomes, leaving their origin in question. The authors now show that one origin of these particles is the midbody—the membrane structure that transiently connects two daughter cells and contains the contractile ring.

The group identified the midbody as the source by examining EMs of neural tissue serial sections. They showed that particles emerge from midbodies of dividing neuroepithelial cells. The midbody particles are released at a developmental stage when these cells...