The ABCs of species evolution

Nearly four decades of study by scientists at the Japan Institute for Integrated Cell Material Sciences (iCeMS) suggest that a family of transport proteins has been important in the evolution of species. One protein in particular, called ABCA1, tended to be essential for vertebral evolution by helping to regulate when signals involved in cell proliferation, differentiation, and migration are transmitted. into your cell. This process was necessary for the spine to grow into more complex organisms with solemn bodily structures.

The ATP-binding (ABC) binding proteins are very similar across species, including bacteria, plants and animals. There are different types of ABC proteins with different transport functions, injecting nutrients into cells, injecting toxic fertilizers outside of them, and regulating lipid density within membranes. cells.

ICeMS cellular biochemist Kazumitsu Ueda has studied human ABC proteins for 35 years, ever since he and his colleagues named the first eukaryote protein ABC gene.

“We believe that ABC proteins must play an important role in evolution,” Ueda says. “By transporting lipids, they allowed plants and animals to thrive on land by protecting them from water loss and pathogen infection. They are also thought to have accelerated vertebra evolution by releasing cholesterol. act as a sign molecule inside a membrane. “

Organisms that existed early in Earth’s history may have been made of DNA and proteins surrounded by a leaky lipid membrane. As the organisms developed, their organs were strengthened to protect them from the external environment. But this meant that only organisms developed by specific ABC carriers that were able to carry nutrients throughout the organs were alive. The ABC proteins played an important role in the generation of an outer membrane that protected cells from external pressures and in the removal of harmful substances from the inside.

Recently, Ueda and his team studied the roles of ABCA1, gaining a deeper insight into how it regulates cholesterol. In particular, they found that ABCA1 releases cell phospholipids and extracellular cholesterol for the generation of high-density lipoproteins, often called good cholesterol.

They also found that ABCA1 constantly transfers cholesterol from the inner membrane of the cell membrane to its outer membrane, maintaining a lower density on the inside. This flopping is held for a period of time when the cell is exposed to external stimuli, such as growth hormone. The accumulation of cholesterol in the inner lining as a result stimulates the recruitment of proteins to the membrane and alters the transmission of the signals. Ueda and his team suggest that ABCA1 allowed the spinal cord to advance complex biological processes and solemn bodies.

“ABCA1 is very special and its actions surprised us,” says Ueda. “The role of cholesterol was thought to be to focus primarily on physically strengthening the cell membrane and reducing its reactivity to ions. Our research suggests that it played a more important role in spines, accelerating their evolution. “

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DOI: 10.1002 / 1873-3468.13945

At iCeMS, our mission is to explore the mysteries of life by creating fertilizers to control cells, and further down the road to create life – inspired substances. https: //www.icems.kyoto-u.ac.jp /

I. Mindy Takamiya / Mari Toyama

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