Tyrosine kinase, PI3K, and p38 MAPK's involvement in LTA-mediated NF-κB-specific DNA-protein complex formation in nuclear extracts of RAW 264.7 macrophages. RAW 264.7 macrophages were pretreated with 100 nm wortmannin, 30 µm LY 294002, 20 µm tyrphostin AG126, 30 µm genistein (a), or 0·1–10 µm SB 203580 (b) for 30 min before incubation with 10 µg/ml LTA for 30 min. Nuclear extracts were prepared for determination of NF-κB-specific DNA-protein binding activity by EMSA as described in ‘Materials and methods’. In (c) and (d), the extent of NF-κB activation was quantitated using a densitometer with Image-Pro plus software. Results are expressed as the mean ± SEM (n = 3). *P < 0·05 as compared with the LTA-treated group. Wort, wortmannin; LY, LY 294002; Tyrp, tyrphostin AG126; Geni, genistein; SB, SB 203580; FP, free probe.