Activation State of Primary Human B Cells Measured by Quantitation of Phosphorylation on Syk Kinase Linker Region Tyrosines

摘要

BTLA, via HVEM, attenuates human B cell proliferation. Phosphorylation of BTLA C-terminus leads to SHP1 recruitment. Recruitment of SHP1 results in reduced activity of the protein-tyrosine kinase Syk. Quantitative MS analysis confirms the decrease in Syk phosphorylation on tyrosine residues (Tyr~(348/52)) required for Syk activation. BTLA negatively regulates B cell activation.