Western blot analysis of phosphorylation of p38 MAPK and other signal proteins. Osteoblasts were infected with S. pyogenes JRS4 for 0, 15, 30, 60, and 120 min at an MOI of 10. The phosphorylation status of p38 MAPK (A) and the phosphorylation status of ERK1/2 and JNK (B) were analyzed by Western blotting by using antibodies against phospho-p38 MAPK, phospho-ERK1/2, phospho-JNK, total p38 MAPK, total ERK1/2, and total JNK.