This chart shows the underlying motif ditribution in a PhosphoScan® LC-MS/MS experiment using 1526 nonredundant Lys-C digested peptides generated from mouse embryo and immunoprecipitated using PTMScan® Basophilic Kinase Motif [(R/X)(R/X)Xp(S/T)] Immunoaffinity Beads. Phospho-threonine peptides comprised 17% of peptides in this data set while phospho-serine contributed 83%.
The Motif Logo was generated from a PhosphoScan® LC-MS/MS experiment using 1526 nonredundant Lys-C digested peptides derived from mouse embryo immunoprecipitated with PTMScan® Basophilic Kinase Motif [(R/X)(R/X)Xp(S/T)] Immunoaffinity Beads. The logo represents the relative frequency of amino acids in each position surrounding the central phosphorylated residue.
Antibody beads supplied in IAP buffer containing 50% glycerol. Store at -20°C. Do not aliquot the antibody.
PTMScan® Technology employs a proprietary methodology from Cell Signaling Technology (CST) for peptide enrichment by immunoprecipitation using a specific bead-conjugated antibody in conjunction with liquid chromatography (LC) tandem mass spectrometry (MS/MS) for quantitative profiling of post-translational modification (PTM) sites in cellular proteins. These include phosphorylation (PhosphoScan®), ubiquitination (UbiScan®), acetylation (AcetylScan®), and methylation (MethylScan®), among others. PTMScan® Technology enables researchers to isolate, identify, and quantitate large numbers of post-translationally modified cellular peptides with a high degree of specificity and sensitivity, providing a global overview of PTMs in cell and tissue samples without preconceived biases about where these modified sites occur. For more information on PTMScan® Proteomics Services, please visit https://www.cellsignal.com/services/index.html.
As an integral part of the machinery of cellular function, proteins undergo regulation by a variety of post-translational modifications. One of the most prevalent and widely studied PTMs is serine/threonine phosphorylation. Prominent kinases targeting consensus substrate motifs account for tens of thousands of known and predicted sites on more than 13,000 human proteins (1-3). Cell Signaling Technology has developed phospho-Ser/Thr motif antibodies for proteomic profiling of kinase substrates. Arg-directed or AGC-family kinases including PKA, PKG, PKC, Akt, p70 S6 kinase, AMPK, and RSK and are characterized by preference for basic amino acids (Lys or Arg) especially Arg at position -3 relative to the phosphorylated Ser or Thr (1,4). Akt, p70S6 kinase and RSK additionally share specificity for Lys or Arg at position -5 (5). CST™ has developed a Basophilic PTMScan® kit comprising a pool of antibodies that recognize basophilic kinase substrate motifs as a powerful proteomics analysis tool for investigating the regulation of phosphorylation by Arg-directed kinases, as well as for high throughput kinase drug discovery.