Evolutionary constraints of phosphorylation in eukaryotes, prokaryotes and mitochondria
Mol Cell Proteomics. 2010 Aug 5. [Epub ahead of print]
Gnad F, Forner F, Zielinska DF, Birney E, Gunawardena J, Mann M.
High accuracy mass spectrometry has proven a powerful technology for the large scale identification of serine/threonine/tyrosine phosphorylation in the living cell. However, despite many described phosphoproteomes, there has been no comparative study of the extent of phosphorylation and its evolutionary conservation in all domains of life. Here we analyze the results of phosphoproteomic studies performed with the same technology in a diverse set of organisms. For the most ancient organisms, the prokaryotes, only a few hundred proteins have been found to be phosphorylated. Applying the same technology to eukaryotic species resulted in the detection of thousands of phosphorylation events. Evolutionary analysis shows that prokaryotic phosphoproteins are preferentially conserved in all living organisms while site specific phosphorylation is not. Eukaryotic phosphosites are generally more conserved than their non-phosphorylated counterparts (with similar structural constraints) throughout the eukaryotic domain. Yeast and C. elegans are two exceptions indicating that the majority of phosphorylation events evolved after the divergence of higher eukaryotes from yeast and reflecting the unusually large number of nematode specific kinases. Mitochondria present an interesting intermediate link between the prokaryotic and eukaryotic domain. Applying the same technology to this organelle yields 174 phosphorylation sites mapped to 74 proteins. Thus the mitochondrial phosphoproteome is similarly sparse as the prokaryotic phosphoproteomes. As expected from the endosymbiotic theory, phosphorylated as well as non-phosphorylated mitochondrial proteins are significantly conserved in prokaryotes. However, mitochondrial phosphorylation sites are not conserved throughout prokaryotes, consistent with the notion that serine-threonine phosphorylation in prokaryotes occurred relatively recently in evolution. Thus the phosphoproteome reflects major events in the evolution of life.
http://www.ncbi.nlm.nih.gov/pubmed/20688971
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