Supplementary proteomics data. Search results for LC/MS/MS experiments are in the form of Scaffold files (a free viewer can be downloaded from http://www.proteomesoftware.com/products/scaffold/download/). These data identified phosphorylation sites of murine SYK protein in WEHI cells treated with either inorganic mercury (Hg), pervanadate (PV), or BCR activating antibody (Ab). Raw data for quantitation of SYK phosphorylation status of selected sites were obtained using multiple reaction monitoring (MRM) on a TSQ triple quadrupole mass spectrometer. Detailed parameters including peptide and fragment mass lists can be found in the Methods section.