"Science" The inner workings of the membraneless cell compartment

Researchers at the Johns Hopkins School of Medicine report that food science principles helped them determine how unusual droplets in cells hold the tissue and avoid dissolving into other gel-like parts inside the cell
.

The researchers say that their work can promote scientific understanding of cell evolution and help scientists in the food and chemical industries develop better ways to prevent the separation of liquid mixtures
.

There are a group of tiny biological machines called organelles in the cells of all living things
.

Scientists have long believed that these somewhat mysterious droplets may be primitive versions of organelles.
A research team led by Johns Hopkins University conducted further research on laboratory nematodes
.

The research team’s findings on these droplets, called biomolecular condensates, were published in the September 10th issue of Science
.

"I hope this work will help convince scientists that biomolecular condensates are highly complex cellular compartments," said Geraldine Seydoux , associate dean of basic research at the Johns Hopkins University School of Medicine and Howard Hughes Medical Institute researcher Geraldine Seydoux Said the doctor
.

In the 1970s, scientists named the aggregates of biomolecules for the first time as "granules.
" They used electron microscopes to more closely observe the structure of many organisms, including curved organisms called nematodes, which are relatively simple The biological characteristics make it a universal laboratory model for studying everything from modern gene cutting technology to protein structure
.

In 2014, in Seydoux's laboratory, graduate student Jennifer Wang conducted genetic analysis and found a protein called MEG-3 in the P particles of C.
elegans
.

Seydoux said: "What we don't understand is that these proteins may just stay on the outside of the P particles, but they are so indispensable for stabilizing the inside of the particles
.

In January 2020, when Seydoux was looking for suitable words to describe their observations, the mystery remained unsolved
.

Emulsion is a mixture of two liquids that usually do not mix well, such as oil and water
.

Unprocessed milk is naturally unstable, and the fat droplets in milk tend to stick together to reduce the overall surface area between fat molecules
.

In order to prevent the milk from separating and stabilizing the liquid, the milk processor passes the milk through a small needle, which breaks down the fat droplets and coats them with a protein called casein to avoid creating a layer of milk fat fused with fat molecules
.

Seydoux said that it suddenly occurred to her that MEG-3 might have an effect very similar to casein in milk, reducing the surface tension of the droplets and preventing them from fusing together
.

In their experiments, Seydoux and her team showed that the MEG-3 coated PGL-3 droplets remained uniformly separated on the glass slide, and the number of droplets fused with the uncoated aggregates was the former.
Twice as much as possible, resulting in fewer and larger droplets on the slide
.

Seydoux said: "This is a well-known phenomenon in food science, and now we see that it may also occur in cells
.
"

Seydoux and her team also engineered nematode egg cells lacking MEG-3 and found that unencapsulated P particles dissolve more slowly
.
Seydoux said this and other experiments show that MEG-3 not only stabilizes droplets under normal conditions, but also makes droplets react faster when environmental conditions change
.

Seydoux's postdoctoral team sought help from a physical chemistry expert to complete their research, who could guide them to understand the physics of Pickering emulsion
.

A few months ago, Chiu Fan Lee, a bioengineer at Imperial College of London, joined the team.
He helped them identify a missing component in the MEG-3 nematode model: a type called MBK-2.
Enzymes, which help the liquid in the P particles become less viscous
.

Seydoux said: "In short, these experiments provide an explanation for how the primordial soup in the cell aggregates into compartments that can resist fusion and respond to developmental cues
.
"

The team plans to conduct further research to determine the precise physical structure of MEG-3 and more details on how it works
.
They said that if further research is successful, MEG-3 can provide a renewable resource for the development of Pickering emulsions in the food and chemical industries
.

Seydoux and his team have applied for a patent for using MEG-3 as a tool for developing Pickering emulsions
.

###