Paper: A Representative of the Third Domain of Life

Ser/Thr/Tyr Protein Phosphorylation in the Archaeon Halobacterium
salinarum-A Representative of the Third Domain of Life
Michalis Aivaliotis 1, Boris Macek 2, Florian Gnad 2, Peter Reichelt 1,
Matthias Mann 2, Dieter Oesterhelt 1

1 Department of Membrane Biochemistry, Max Planck Institute of Biochemistry,
Martinsried, Germany,
2 Department of Proteomics and Signal Transduction, Max Planck Institute of
Biochemistry, Martinsried, Germany

Abstract
In the quest for the origin and evolution of protein phosphorylation, the
major regulatory post-translational modification in eukaryotes, the members
of archaea, the "third domain of life", play a protagonistic role. A
plethora of studies have demonstrated that archaeal proteins are subject to
post-translational modification by covalent phosphorylation, but little is
known concerning the identities of the proteins affected, the impact on
their functionality, the physiological roles of archaeal protein
phosphorylation/dephosphorylation, and the protein kinases/phosphatases
involved. These limited studies led to the initial hypothesis that archaea,
similarly to other prokaryotes, use mainly histidine/aspartate
phosphorylation, in their two-component systems representing a paradigm of
prokaryotic signal transduction, while eukaryotes mostly use Ser/Thr/Tyr
phosphorylation for creating highly sophisticated regulatory networks. In
antithesis to the above hypothesis, several studies showed that Ser/Thr/Tyr
phosphorylation is also common in the bacterial cell, and here we present
the first genome-wide phosphoproteomic analysis of the model organism of
archaea, Halobacterium salinarum, proving the existence/conservation of
Ser/Thr/Tyr phosphorylation in the "third domain" of life, allowing a better
understanding of the origin and evolution of the so-called "Nature's
premier" mechanism for regulating the functional properties of proteins.

Source: PLoS One [Open Access]
http://www.plosone.org/article/info:doi/10.1371/journal.pone.0004777

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