Cell lysates were collected from LPS-stimulated wild type and Syk-deficient BMDCs at the time points indicated for Western blot analysis. Blots were probed with the antibodies to phospho-and total IKKβ, NF-κBp65 (A, B), P38, ERK (C, D), and GAPDH as a loading control. (B, D) Densitometric quantification of the ratio of phospho- to total proteins.