Passive endocytosis in model protocells

Proc Natl Acad Sci U S A. 2023 Jun 13;120(24):e2221064120. doi: 10.1073/pnas.2221064120. Epub 2023 Jun 5.


Semipermeable membranes are a key feature of all living organisms. While specialized membrane transporters in cells can import otherwise impermeable nutrients, the earliest cells would have lacked a mechanism to import nutrients rapidly under nutrient-rich circumstances. Using both experiments and simulations, we find that a process akin to passive endocytosis can be recreated in model primitive cells. Molecules that are too impermeable to be absorbed can be taken up in a matter of seconds in an endocytic vesicle. The internalized cargo can then be slowly released over hours, into the main lumen or putative cytoplasm. This work demonstrates a way by which primitive life could have broken the symmetry of passive permeation prior to the evolution of protein transporters.

Keywords: budding; lipids; membranes; origin of life; vesicles.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural

MeSH terms

  • Artificial Cells*
  • Endocytosis
  • Transport Vesicles