New insight into the evolution of complex life on Earth

Date:
August 6, 2020
Source:
Lancaster University
Summary:
A novel connection between primordial organisms and complex life
has been discovered, as new evidence sheds light on the evolutionary
origins of the cell division process that is fundamental to complex
life on Earth.



FULL STORY ==========================================================================
A novel connection between primordial organisms and complex life has been discovered, as new evidence sheds light on the evolutionary origins of
the cell division process that is fundamental to complex life on Earth.


==========================================================================
The discovery was made by a cross-disciplinary team of scientists led
by Professor Buzz Baum of University College London and Dr Nick Robinson
of Lancaster University.

Their research, published in Science, sheds light on the cell division
of the microbe Sulfolobus acidocaldarius, which thrives in acidic hot
springs at temperatures of around 75?C. This microbe is classed among
the unicellular organisms called archaea that evolved 3.5 billion years
ago together with bacteria.

Eukaryotes evolved about 1 billion years later -- likely arising from an endosymbiotic event in which an archaeal and bacterial cell merged. The resulting complex cells became a new division of life that now includes
the protozoa, fungi, plants and animals.

Now a common regulatory mechanism has been discovered in the cell division
of both archaea and eukaryotes after the researchers demonstrated for
the first time that the proteasome -- sometimes referred to as the waste disposal system of the cell -- regulates the cell division in Sulfolobus acidocaldarius by selectively breaking down a specific set of proteins.

The authors report: "This is important because the proteasome has not previously been shown to control the cell division process of archaea."
The proteasome is evolutionarily conserved in both archaea and eukaryotes
and it is already well established that selective proteasome-mediated
protein degradation plays a key role in the cell cycle regulation of eukaryotes.

These findings therefore shed new light on the evolutionary history of
the eukaryotes.

The authors summarise: "It has become increasingly apparent that the
complex eukaryotic cells arose following an endosymbiotic event between an ancestral archaeal cell and an alpha-proteobacterium, which subsequently
became the mitochondria within the resulting eukaryotic cell. Our study suggests that the vital role of the proteasome in the cell cycle of all eukaryotic life today has its evolutionary origins in archaea."

========================================================================== Story Source: Materials provided by Lancaster_University. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Gabriel Tarrason Risa, Fredrik Hurtig, Sian Bray, Anne E. Hafner,
Lena
Harker-Kirschneck, Peter Faull, Colin Davis, Dimitra Papatziamou,
Delyan R. Mutavchiev, Catherine Fan, Leticia Meneguello, Andre
Arashiro Pulschen, Gautam Dey, Sia^n Culley, Mairi Kilkenny,
Diorge P. Souza, Luca Pellegrini, Robertus A. M. De Bruin, Ricardo
Henriques, Ambrosius P.

Snijders, Anđela Sarić, Ann-Christin Lindaas, Nicholas P.

Robinson, Buzz Baum. The proteasome controls ESCRT-III-mediated cell
division in an archaeon. Science, 2020 DOI: 10.1126/science.aaz2532 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200806153557.htm

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