Figure 5.

Syk is required for FcγRIIIb-mediated TAK1 activation. Human neutrophils were left untreated (---), or were stimulated by cross-linking FcγRIIIb for 15 min in the absence or presence of 50 μM Piceatannol (Pic) or 40 nM iSyk, both selective inhibitors of Syk. Cell lysates were prepared after stimulation. Proteins were resolved by SDS-PAGE and then Western blotted for phosphorylated-TAK1 (pTAK1) (upper panel), or for phosphorylated ERK (pERK) (middle panel), and for total glyceraldehyde 3-phosphate dehydrogenase (GAPDH) (lower panel). Data are representative of three separate experiments.