Syk and pTyr'd: Signaling through the B cell antigen receptor

Abstract

The B cell receptor (BCR) transduces antigen binding into alterations in the activity of intracellular signaling pathways through its ability to recruit and activate the cytoplasmic protein-tyrosine kinase Syk. The recruitment of Syk to the receptor, its activation and its subsequent interactions with downstream effectors are all regulated by its phosphorylation on tyrosine. This review discusses our current understanding of how this phosphorylation regulates the activity of Syk and its participation in signaling through the BCR.

Fig. 1

Model of Syk showing approximate locations of major sites of tyrosine-phosphorylation.

Fig. 2

A stick representation (magenta) of the Syk linker B peptide showing the two phosphoryl groups by ball-and-sticks (blue). The pY342 residue is on the right and pY346 on the left. The SH2 domain is shown using a solvent accessible surface representation where the contact region within 5 angstrom of the peptide is colored tan.