Additional file 2: of Mercury alters endogenous phosphorylation profiles of SYK in murine B cells

Consensus SYK phosphorylation sites. Singly, doubly or triply phosphorylated peptides were scored for peptide identification probability and modification site localization probability. Cutoff for accepted phosphosites was a localization probability of ≥95%. Data represent top scoring peptides. (PDF 219 kb

Additional file 1: of Mercury alters endogenous phosphorylation profiles of SYK in murine B cells

SYK protein sequencing coverage. These data represent results from a single anti-SYK immunoprecipitation experiment with WEHI cell extracts. The sample was digested with trypsin and analyzed by LC-MS/MS. MS2 spectral identifications were scored with Mascot and X!Tandem algorithms against forward and scrambled murine protein databases. Positive identifications were assigned below a 1% FDR threshold. (PDF 254 kb

Mercury Alters B‑Cell Protein Phosphorylation Profiles

Environmental exposure to mercury is suggested to contribute to human immune dysfunction. To shed light on the mechanism, we identified changes in the phosphoproteomic profile of the WEHI-231 B cell line after intoxication with Hg²⁺. These changes were compared to changes in the phosphoproteome that were induced by pervanadate or okadaic acid exposure. Both 250 μM HgCl₂ and pervanadate, a known phosphotyrosine phosphatase inhibitor, caused an increase in the number of proteins identified after TiO₂ affinity selection and LC-MS/MS analysis. Pervanadate treatment had a larger effect than Hg²⁺ on the number of Scansite motifs that were tyrosine-phosphorylated, 17, and Ingenuity canonical signaling pathways activated, 4, with score >5.0. However, Hg²⁺ had a more focused effect, primarily causing tyrosine-phosphorylation in src homology 2 domains in proteins that are in the B cell receptor signaling pathway. The finding that many of the changes induced by Hg²⁺ overlap with those of pervanadate, indicates that at high concentrations Hg²⁺ inhibits protein tyrosine phosphatases

Mercury Alters B‑Cell Protein Phosphorylation Profiles

Environmental exposure to mercury is suggested to contribute to human immune dysfunction. To shed light on the mechanism, we identified changes in the phosphoproteomic profile of the WEHI-231 B cell line after intoxication with Hg²⁺. These changes were compared to changes in the phosphoproteome that were induced by pervanadate or okadaic acid exposure. Both 250 μM HgCl₂ and pervanadate, a known phosphotyrosine phosphatase inhibitor, caused an increase in the number of proteins identified after TiO₂ affinity selection and LC-MS/MS analysis. Pervanadate treatment had a larger effect than Hg²⁺ on the number of Scansite motifs that were tyrosine-phosphorylated, 17, and Ingenuity canonical signaling pathways activated, 4, with score >5.0. However, Hg²⁺ had a more focused effect, primarily causing tyrosine-phosphorylation in src homology 2 domains in proteins that are in the B cell receptor signaling pathway. The finding that many of the changes induced by Hg²⁺ overlap with those of pervanadate, indicates that at high concentrations Hg²⁺ inhibits protein tyrosine phosphatases