A team of biologists from the University of Virginia and the National Institutes of Health has found that half of certain organelles can make up to 10% of vesicle organelles present in cells, yet they do not follow the typical endocytotic pathway.

Cutting-edge Cryo-Electron microscope images of rat-1 cells cultured on Cryo-EM grids. The lamellipodia and filopodia in the upper right corner illustrate the cell boundary, distinguishing the cytoplasm from the extracellular space (ext). Various vesicle organelles are highlighted, including early endosomal-like vesicles (EN, pink), multinuclear bodies (MVB, blue), hemispores (HF, yellow), and inverted hemifusomes (FHF, green). Scale bar – 0.5 µm. Image credit: Tavakoli et al., doi: 10.1038/s41467-025-59887-9.

“It’s like uncovering a new recycling center within a cell,” remarked Dr. Seham Ebrahim, a researcher at the University of Virginia.

“Many believe it plays a role in how cells manage their packaging and processing of materials. If this process fails, it can lead to diseases affecting multiple systems in the body.”

“One such condition is Hermansky-Pudlak syndrome, a rare genetic disorder that may result in albinism, visual impairments, lung issues, and problems with blood clotting.”

“The challenges related to how cells manage their cargo are central to many of these issues.”

“We’re just beginning to grasp how these new organelles fit into the broader context of cellular health and disease.”

“This discovery is thrilling because finding a genuinely new internal cell is rare, and it opens up avenues for exploring entirely new paths.”

Utilizing Cryo-Electron tomography (Cryo-ET), the researchers managed to capture a significant number of images.

They propose that these organelles facilitate the creation of vesicle-based organelles, which function like mixing bowls, small blister-like sacs, and multiple vesicles.

This process plays a critical role in cellular sorting, recycling, and debris management.

Dr. Ebrahim stated, “You can think of vesicles as small delivery trucks within a cell.”

“Part of it functions like a loading dock where cargo is connected and transferred. It’s a step in the process we were unaware of.”

Many of these organelles have gone unnoticed but are surprisingly prevalent in certain areas of the cell.

Researchers aim to enhance their understanding of their significance in proper cell functioning and how issues with them can lead to diseases.

Such findings may contribute to targeted treatments for a range of serious genetic disorders.

“This is only the beginning,” Dr. Ebrahim noted.

“Now that we’ve confirmed the existence of hemifusomes, we can explore their behavior in healthy cells and investigate what occurs when problems arise.”

“It could pave the way for new strategies to address complex genetic disorders.”

The team’s paper was published in the journal Nature Communications.

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A. Cigarette et al. 2025. Proteolipid nanosap interacting with half of hemifusomes mediates polyspore formation. Nat Commun 16, 4609; doi:10.1038/s41467-025-59887-9