Cells have more mini ‘organs’ than researchers thought − unbound by membranes, these rogue organelles challenge biology’s fundamentals

Very recommendable! Amazing stuff!

"... Membrane-bound organelles were the textbook standard of how scientists thought cells were organized until they realized in the mid-2000s that some organelles don’t need to be wrapped in a membrane. Since then, researchers have discovered many additional membraneless organelles that have significantly changed how biologists think about the chemistry and origins of life. ...

As of 2022, researchers have found about 30 kinds of these membraneless biomolecular condensates. In comparison, there are around a dozen known traditional membrane-bound organelles.

Although easy to identify once you know what you are looking for, it’s difficult to figure out what biomolecular condensates exactly do. Some have well-defined roles, such as forming reproductive cells, stress granules and protein-making ribosomes. However, many others don’t have clear functions. ...

The proteins that form biomolecular condensates at least partially break this rule since they contain regions that are disordered, meaning they do not have defined shapes. When researchers discovered these so-called intrinsically disordered proteins, or IDPs, in the early 1980s, they were initially confounded by how these proteins could lack a strong structure but still perform specific functions.

Later, they found that IDPs tend to form condensates. ...

Researchers have also detected biomolecular condensates in prokaryotic, or bacterial, cells, which traditionally were defined as not containing organelles. This finding could have profound effects on how scientists understand the biology of prokaryotic cells.

Only about 6% of bacterial proteins have disordered regions lacking structure, compared with 30% to 40% of eukaryotic, or nonbacterial, proteins. But scientists have found several biomolecular condensates in prokaryotic cells that are involved a variety of cellular functions, including making and breaking down RNAs. ...

With the discovery that RNAs can spontaneously form biomolecular condensates, lipids [for cell membranes] wouldn’t be needed to form protocells. ..."

Cells have more mini ‘organs’ than researchers thought − unbound by membranes, these rogue organelles challenge biology’s fundamentals

Inclusion bodies, stained magenta in this micrograph of herpesvirus 6, are aggregates of proteins that form a type of biomolecular condensate.