Scientists map 1,000 molecular tools common to cells across tree of life

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.

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.

Many protein assemblies in humans identical to other 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.

Written by Catharine Paddock PhD

Copyright: Medical News Today