Schwartz, D. & Gygi, S.P. An iterative statistical approach to the identification of protein phosphorylation motifs from large-scale data sets. Nat. Biotechnol. 23, 1391-1398

Department of Cell Biology, 240 Longwood Ave., Harvard Medical School, Boston, Massachusetts 02115, USA.
Nature Biotechnology (Impact Factor: 41.51). 12/2005; 23(11):1391-8. DOI: 10.1038/nbt1146
Source: PubMed


With the recent exponential increase in protein phosphorylation sites identified by mass spectrometry, a unique opportunity has arisen to understand the motifs surrounding such sites. Here we present an algorithm designed to extract motifs from large data sets of naturally occurring phosphorylation sites. The methodology relies on the intrinsic alignment of phospho-residues and the extraction of motifs through iterative comparison to a dynamic statistical background. Results show the identification of dozens of novel and known phosphorylation motifs from recently published serine, threonine and tyrosine phosphorylation studies. When applied to a linguistic data set to test the versatility of the approach, the algorithm successfully extracted hundreds of language motifs. This method, in addition to shedding light on the consensus sequences of identified and as yet unidentified kinases and modular protein domains, may also eventually be used as a tool to determine potential phosphorylation sites in proteins of interest.

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    • "For motif analysis, the 10 amino acid residues (-10 to +10) on either side of a modification site were selected, and a consensus logo was generated using the iceLogo webserver [53] . We also analyzed the same sets of data using the motif-X webserver [54] to confirm the sequence preferences (S4Fig). All information for the protein annotations, the positions of acyl modifications, and their surrounding sequences are shown in S2 Table. "
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    ABSTRACT: Lysine residues can be post-translationally modified by various acyl modifications in bacteria and eukarya. Here, we showed that two major acyl modifications, acetylation and succinylation, were changed in response to the carbon source in the Gram-positive model bacterium Bacillus subtilis. Acetylation was more common when the cells were grown on glucose, glycerol, or pyruvate, whereas succinylation was upregulated when the cells were grown on citrate, reflecting the metabolic states that preferentially produce acetyl-CoA and succinyl-CoA, respectively. To identify and quantify changes in acetylation and succinylation in response to the carbon source, we performed a stable isotope labeling by amino acids in cell culture (SILAC)-based quantitative proteomic analysis of cells grown on glucose or citrate. We identified 629 acetylated proteins with 1355 unique acetylation sites and 204 succinylated proteins with 327 unique succinylation sites. Acetylation targeted different metabolic pathways under the two growth conditions: branched-chain amino acid biosynthesis and purine metabolism in glucose and the citrate cycle in citrate. Succinylation preferentially targeted the citrate cycle in citrate. Acetylation and succinylation mostly targeted different lysine residues and showed a preference for different residues surrounding the modification sites, suggesting that the two modifications may depend on different factors such as characteristics of acyl-group donors, molecular environment of the lysine substrate, and/or the modifying enzymes. Changes in acetylation and succinylation were observed in proteins involved in central carbon metabolism and in components of the transcription and translation machineries, such as RNA polymerase and the ribosome. Mutations that modulate protein acylation affected B. subtilis growth. A mutation in acetate kinase (ackA) increased the global acetylation level, suggesting that acetyl phosphate-dependent acetylation is common in B. subtilis, just as it is in Escherichia coli. Our results suggest that acyl modifications play a role in the physiological adaptations to changes in carbon nutrient availability of B. subtilis.
    Full-text · Article · Jun 2015 · PLoS ONE
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    • "To assess a potential preference for certain kinase motifs in the five phosphopeptides data sets, we subjected the hereidentified phosphorylation sites first to the motif-x algorithm (Schwartz and Gygi, 2005). A total of 132 distinct motifs could be defined among all the five proteases data sets (Table S3). "
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    ABSTRACT: Although mass-spectrometry-based screens enable thousands of protein phosphorylation sites to be monitored simultaneously, they often do not cover important regulatory sites. Here, we hypothesized that this is due to the fact that nearly all large-scale phosphoproteome studies are initiated by trypsin digestion. We tested this hypothesis using multiple proteases for protein digestion prior to Ti(4+)-IMAC-based enrichment. This approach increases the size of the detectable phosphoproteome substantially and confirms the considerable tryptic bias in public repositories. We define and make available a less biased human phosphopeptide atlas of 37,771 unique phosphopeptides, correlating to 18,430 unique phosphosites, of which fewer than 1/3 were identified in more than one protease data set. We demonstrate that each protein phosphorylation site can be linked to a preferred protease, enhancing its detection by mass spectrometry (MS). For specific sites, this approach increases their detectability by more than 1,000-fold. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.
    Full-text · Article · Jun 2015 · Cell Reports
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    • "Thus, the two studies provide different but complementary rapamycin-regulated phosphoproteomes. To determine if TORC1 controls phosphorylation of specific motifs, we analyzed the sequences surrounding the rapamycin-regulated phosphosites, with the Motif-X algorithm (Schwartz and Gygi, 2005). For the peptides "
    Dataset: 3475-3

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