Details

Autor(en) / Beteiligte

• Caruso, Joseph A.
• Stemmer, Paul M.
• Dombkowski, Alan
• Caruthers, Nicholas J.
• Gill, Randall
• Rosenspire, Allen J.

Titel

A systems toxicology approach identifies Lyn as a key signaling phosphoprotein modulated by mercury in a B lymphocyte cell model

Ist Teil von

• Toxicology and applied pharmacology, 2014-04, Vol.276 (1), p.47-54

Ort / Verlag

Amsterdam: Elsevier Inc

Erscheinungsjahr

2014

Link zum Volltext

Quelle

MEDLINE

Beschreibungen/Notizen

• Network and protein–protein interaction analyses of proteins undergoing Hg2+-induced phosphorylation and dephosphorylation in Hg2+-intoxicated mouse WEHI-231 B cells identified Lyn as the most interconnected node. Lyn is a Src family protein tyrosine kinase known to be intimately involved in the B cell receptor (BCR) signaling pathway. Under normal signaling conditions the tyrosine kinase activity of Lyn is controlled by phosphorylation, primarily of two well known canonical regulatory tyrosine sites, Y-397 and Y-508. However, Lyn has several tyrosine residues that have not yet been determined to play a major role under normal signaling conditions, but are potentially important sites for phosphorylation following mercury exposure. In order to determine how Hg2+ exposure modulates the phosphorylation of additional residues in Lyn, a targeted MS assay was developed. Initial mass spectrometric surveys of purified Lyn identified 7 phosphorylated tyrosine residues. A quantitative assay was developed from these results using the multiple reaction monitoring (MRM) strategy. WEHI-231 cells were treated with Hg2+, pervanadate (a phosphatase inhibitor), or anti-Ig antibody (to stimulate the BCR). Results from these studies showed that the phosphoproteomic profile of Lyn after exposure of the WEHI-231 cells to a low concentration of Hg2+ closely resembled that of anti-Ig antibody stimulation, whereas exposure to higher concentrations of Hg2+ led to increases in the phosphorylation of Y-193/Y-194, Y-501 and Y-508 residues. These data indicate that mercury can disrupt a key regulatory signal transduction pathway in B cells and point to phospho-Lyn as a potential biomarker for mercury exposure. •Inorganic mercury (Hg2+) induces changes in the WEHI-231 B cell phosphoproteome.•The B cell receptor (BCR) signaling pathway was the pathway most affected by Hg2+.•The Src family phosphoprotein kinase Lyn was the most interconnected node.•Lyn is likely central to the immunotoxic potential of Hg2+.•Lyn phosphorylation profiles may be biomarkers for Hg2+ intoxication of B cells.