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Making the most of what you have


Tue, 28/02/2012 - 15:05

Making the most of what you have

Bacterium fine-tunes proteins for enhanced functionality
The bacterium Mycoplasma pneumoniae, which causes atypical pneumonia, is helping scientists uncover how cells make the most of limited resources. By measuring all the proteins this bacterium produces, scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany and collaborators, have found that the secret is fine-tuning.
Like a mechanic can fine-tune a car after it has left the factory, cells have ways to tweak proteins, changing their chemical properties after production – so-called post-translational modifications. Anne-Claude Gavin, Peer Bork and colleagues at EMBL measured how many of M. pneumoniae’s proteins had certain modifications. They found that two forms of tweaking which were known to be common in our own cells are equally prevalent in this simple bacterium. Called phosphorylation and lysine acetylation, these two types of post-translational modification also talk to and interfere with each other: the scientists found that disrupting one can cause changes in the other. Since M. pneumoniae is one of the living organisms with the fewest different proteins, this interplay between phosphorylation and lysine acetylation may be a way of getting additional functions out of a limited number of proteins: by tweaking each protein in several ways, enabling it to perform a variety of tasks. And, as more complex cells like our own share the same protein-tweaking tactics, it is probably an ancient strategy that evolved before our branch of the evolutionary tree and M. pneumoniae’s branched their separate ways.
The scientists also found that phosphorylation levels in M. pneumoniae control how much of each protein the bacterium has. Interestingly, it does so not only by influencing whether protein-building instructions encoded in DNA are read, but also by altering proteins that are involved in building other proteins. This fine-tuning may enable the cell to react faster to changing needs or situations.
When they disrupted M. pneumoniae’s ability to tweak proteins, Gavin, Bork and colleagues also discovered that disaster doesn’t necessarily ensue. As in our own cells, proteins in this bacterium rarely work alone. They interact with each other, work together, or perform different steps in chain reactions. The scientists found that these protein networks have a certain buffering ability: disrupting one protein can affect its immediate partners, but the problems may not propagate throughout the whole network. The scientists hope that mapping the different networks may one day enable them to predict where a targeted disruption might do the most damage, which could eventually provide valuable information for drug design.
The work, published online today in Molecular Systems Biology, was conducted in collaboration with the Centre for Genomic Regulation in Barcelona, Spain, Utrecht University in the Netherlands, and Georg-August University Göttingen and Heidelberg University, both in Germany.
Moreover, this work provides new information about Mycoplasma pneumoniae and it contributes to Luis Serrano's project at CRG, which is focused on this bacterium. It will help us understanding this simple and small bacterium, which could be useful, for example, as a vector to treat diseases in the future.
About EMBL
The European Molecular Biology Laboratory is a basic research institute funded by public research monies from 20 member states (Austria, Belgium, Croatia, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Israel, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom) and associate member state Australia. Research at EMBL is conducted by approximately 85 independent groups covering the spectrum of molecular biology. The Laboratory has five units: the main Laboratory in Heidelberg, and Outstations in Hinxton (the European Bioinformatics Institute), Grenoble, Hamburg, and Monterotondo near Rome. The cornerstones of EMBL’s mission are: to perform basic research in molecular biology; to train scientists, students and visitors at all levels; to offer vital services to scientists in the member states; to develop new instruments and methods in the life sciences and to actively engage in technology transfer activities. Around 190 students are enrolled in EMBL’s International PhD programme. Additionally, the Laboratory offers a platform for dialogue with the general public through various science communication activities such as lecture series, visitor programmes and the dissemination of scientific achievements.
Source article: 
van Noort, V., Seebacher, J., Bader, S. et al. Cross-talk between phosphorylation and lysine acetylation in a genome-reduced bacterium. Molecular Systems Biology, 28 February 2012.
Please, read the official EMBL press release, here.