Scientists have discovered hemifusomes, a previously unknown membrane structure, within eukaryotic cells using cryo-electron tomography. This discovery could fundamentally change our understanding of how cells transport substances via vesicles. The new research was published in Nature Communications.
Transport Mechanism
Vesicular transport is a process where substances are enclosed in specialized sacs, called vesicles, within the cell and moved from one area to another. This is crucial for intracellular communication and substance exchange.
A hemifusome is a structure formed when two vesicles partially fuse, creating a shared diaphragm (membrane) between them. This process is accompanied by unique proteolipid nanodroplets (PNDs).
Interestingly, hemifusomes operate independently of the well-known ESCRT protein system. This suggests the possibility of alternative pathways for vesicle formation.
Scientists have described two forms of hemifusomes: direct and inverted, which operate through different mechanisms of membrane fusion. This discovery may be significant in explaining processes such as cellular waste recycling, signal regulation, and the development of neurodegenerative diseases.
The next stage of the research aims to determine whether PND particles can independently guide vesicle formation and potentially serve as a platform for targeted drug delivery.
Reference
Tavakoli, A., Hu, S., Ebrahim, S. et al. Hemifusomes and interacting proteolipid nanodroplets mediate multi-vesicular body formation. Nature Communications 16, 4609 (2025).
