title: Proteome-wide survey of phosphorylation patterns affected by nuclear DNA polymorphisms in Arabidopsis thaliana.
abstract: BACKGROUND
  Protein phosphorylation is an important post-translational modification influencing many aspects of dynamic cellular behavior. Site-specific phosphorylation of amino acid residues serine, threonine, and tyrosine can have profound effects on protein structure, activity, stability, and interaction with other biomolecules. Phosphorylation sites can be affected in diverse ways in members of any species, one such way is through single nucleotide polymorphisms (SNPs). The availability of large numbers of experimentally identified phosphorylation sites, and of natural variation datasets in Arabidopsis thaliana prompted us to analyze the effect of non-synonymous SNPs (nsSNPs) onto phosphorylation sites.
  
  
  RESULTS
  From the analyses of 7,178 experimentally identified phosphorylation sites we found that: (i) Proteins with multiple phosphorylation sites occur more often than expected by chance. (ii) Phosphorylation hotspots show a preference to be located outside conserved domains. (iii) nsSNPs affected experimental phosphorylation sites as much as the corresponding non-phosphorylated amino acid residues. (iv) Losses of experimental phosphorylation sites by nsSNPs were identified in 86 A. thaliana proteins, among them receptor proteins were overrepresented.These results were confirmed by similar analyses of predicted phosphorylation sites in A. thaliana. In addition, predicted threonine phosphorylation sites showed a significant enrichment of nsSNPs towards asparagines and a significant depletion of the synonymous substitution. Proteins in which predicted phosphorylation sites were affected by nsSNPs (loss and gain), were determined to be mainly receptor proteins, stress response proteins and proteins involved in nucleotide and protein binding. Proteins involved in metabolism, catalytic activity and biosynthesis were less affected.
  
  
  CONCLUSIONS
  We analyzed more than 7,100 experimentally identified phosphorylation sites in almost 4,300 protein-coding loci in silico, thus constituting the largest phosphoproteomics dataset for A. thaliana available to date. Our findings suggest a relatively high variability in the presence or absence of phosphorylation sites between different natural accessions in receptor and other proteins involved in signal transduction. Elucidating the effect of phosphorylation sites affected by nsSNPs on adaptive responses represents an exciting research goal for the future.
authors.affiliation: Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany.
authors.forename: Diego Mauricio
authors.initials: DM
authors.lastname: Riaño-Pachón
authors.forename: Sabrina
authors.initials: S
authors.lastname: Kleessen
authors.forename: Jost
authors.initials: J
authors.lastname: Neigenfind
authors.forename: Pawel
authors.initials: P
authors.lastname: Durek
authors.forename: Elke
authors.initials: E
authors.lastname: Weber
authors.forename: Wolfgang R
authors.initials: WR
authors.lastname: Engelsberger
authors.forename: Dirk
authors.initials: D
authors.lastname: Walther
authors.forename: Joachim
authors.initials: J
authors.lastname: Selbig
authors.forename: Waltraud X
authors.initials: WX
authors.lastname: Schulze
authors.forename: Birgit
authors.initials: B
authors.lastname: Kersten
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000378:metabolism*; D001665:Binding Sites; D002467:Cell Nucleus / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D010766:Phosphorylation; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D020543:Proteome / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D018744:DNA, Plant; D010940:Plant Proteins; D020543:Proteome