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| Heidelberg,
Copenhagen, 3 February 2005 |
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| Biology in four dimensions |
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| Temporal
protein interaction network of the yeast mitotic
cell cycle. | |
Press Release 3 February 2005 [PDF]
[Danish]
The factor of time gives scientists insight into cellular machines
Most things that happen in the cell are the work
of 'molecular machines' – complexes of proteins
that carry out important cellular functions. Until
now, scientists didn't have a clear idea of when
proteins form these machines – are these complexes
pre-fabricated or put together on the spot for each
specific job? Researchers at the European Molecular
Biology Laboratory [EMBL], working closely with
scientists from the Technical University of Denmark
[DTU], have now answered that question by drawing
together many types of data in a fascinating new
model. The work is published in this week's edition
of Science.
"Past studies of this type have usually left out a crucial
element Æ time," says EMBL Group Leader Peer Bork.
"But now a picture has emerged which is extremely
dynamic."
The researchers discovered that in yeast, key
components needed to create a machine are produced
ahead of time, and kept in stock. When a new machine is
needed, a few crucial last pieces are synthesized and
then the apparatus is assembled. Holding off on the last
components enables the cell to prevent building machines
at the wrong times. That's a different scenario from what
happens in bacteria, which usually start production of all
the parts, from scratch, whenever they want to get
something done.
"We saw a clear pattern as to how the complexes are
assembled," says SĀren Brunak from DTU. "It's unusual
to find such concrete patterns in biology, compared to
physics for example, due to the evolutionary forces that
change living systems. But using this new model, the
underlying principle became very clear."
The researchers developed the model by combining data
from many different studies. First, they analyzed existing
protein-protein interaction data to construct a network that
traces the pieces of each complex and shows how they
interact. Then, to add the dimension of time, they
identified genes involved in the cell cycle to find out when
certain genes are switched on to produce the proteins that
assemble into cellular machines. By overlaying various
data sets, the researchers were able to construct a new
model for protein-complex interactions.
"In addition to gaining new information about known
cellular machines," Bork notes, "we were able to plug in
some components whose functions had been unknown.
And the same approach could be used to study the
dynamic behaviour of other biological systems, including
those of humans and animals."
Source Article Dynamic complex formation during the yeast
cell cycle.
Ulrik de Lichtenberg*, Lars Juhl Jensen*, SĀren
Brunak and Peer Bork.
Science. February 4, 2004.
[*These authors contributed equally.]
For copies of this Science paper, please contact the AAAS Office of Public Programs,
Tel: +1 202 326 6440, E-mail: scipak@aaas.org.
Press Contact Søren Brunak,
Professor, centerleder, CBS, DTU,
Bygning 208, 2800 Lyngby, Danmark
Tel: +45 [0] 4525 2477 or 2067 2477
E-mail: brunak@cbs.dtu.dk
Website: www.cbs.dtu.dk
Trista Dawson
EMBL Press Officer, European Molecular Biology Laboratory,
Meyerhofstrasse 1, 69117 Heidelberg, Germany
Tel: +49 [0] 6221 3878452
E-mail: trista.dawson@embl.de |
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