A huge new study shows that across the tree of life, species as diverse as worms, mice, humans and sea anemones share many of the protein machines that help their cells to function.

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The researchers found protein assemblies in humans were often identical to those in other species.
Image credit: Jovana Drinkjakovic

The new study, involving seven research groups from three countries and led by researchers from the University of Texas (UT) at Austin and the University of Toronto in Canada, is published in the journal Nature. It is one of the largest and most detailed pieces of research on animal molecular biology ever undertaken.

Cells use complex combinations of proteins as tools to carry out essential processes – for example, cell growth and repair, transport and recycling of materials and signaling between cells.

The new study maps the assembly instructions for nearly 1,000 protein complexes that are identical in cells of species representing a broad cross-section of the animal kingdom, revealing their shared evolution.

One of the senior authors Edward Marcotte, a professor of molecular biosciences at UT Austin, says:

“Essentially, we were able to construct a sort of assembly diagram of how thousands of different proteins come together to carry out their proper roles inside the cells of most kinds of animals.”

Prof. Marcotte and colleagues used techniques like high-throughput mass spectrometry to analyze cell proteins from organisms ranging from slime mold, yeast, worms, sea urchins and sea anemones to flies, frogs, mice and humans.

They then cross-referenced the mass spectrometry data with information already known about the genomes of these species.

The map also details the network of protein-to-protein interactions that take place when the proteins come together to form the complexes.

For example, it shows that a protein whose role we do not yet know is likely to be involved in fixing damage in a cell if it sticks to cell’s known “handymen” proteins.

This is like finding the instruction manual for making different transformer toys from the basic building blocks, and not only this, but also how to put transformers together to make bigger ones.

The researchers also found protein assemblies in humans were often identical to those in other species. For example, they found that identical protein complexes are used by cells to form the head and eye across the different species.

Co-senior author Andrew Emili, a professor in molecular genetics at Toronto, says for him the highlight of the study was its sheer scale:

“We have tripled the number of known protein interactions for every species. So across all the animals, we can now predict, with high confidence, more than 1 million protein interactions – a fundamentally ‘big step’ moving the goal posts forward in terms of protein interaction networks.”

If even one of these interactions is disrupted or lost, it can lead to disease. Thus the map – which will available to researchers worldwide through open access databases – will be a powerful tool for studying the causes of diseases like Alzheimer’s disease, Parkinson’s disease and cancer.

The findings also reveal that tens of thousands of protein interactions have not changed since the first ancestral cell appeared 1 billion years ago – preceding all of animal life on Earth.

Prof. Marcotte summarizes the value of the new data:

This not only reinforces what we already know about our common evolutionary ancestry, it also has practical implications, providing the ability to study the genetic basis for a wide variety of diseases and how they present in different species.”

Meanwhile, Medical News Today recently learned that scientists have also mapped the gene activity of a human embryo’s first days. The study, published in Nature Communications and led by the Karolinska Institutet in Sweden, should lead to new research avenues and treatments for infertility and other diseases.