Here it must be emphasized that both KN62 and SB203580 are reported as highly specific inhibitors of CaMKII and p38 activity thus selleck chem inhibitor excluding the possibility of off target effects that might arise. The perturbations in the BCR signaling network induced by these two pharmacological inhibitors also resulted in profound effects at the level of the BCR sensitive TFs. This is apparent from the heat map shown in Figure 5B, which compares the fold change in activity Inhibitors,Modulators,Libraries of individual TFs at 20 and 40 minutes of stimu lation with anti IgM either in the absence or presence of these inhibitors. The green and red maps represent a 2 fold repression and activation respectively, while the grey map is indicative of no change in activity.

Broadly speaking, it is evident that both the inhibitors Inhibitors,Modulators,Libraries employed significantly attenuate the effects of anti IgM, during either the enhancement or suppression of TF activities. For our further analysis, we concentrated on examin ing the activation profiles of only those seven TFs that were short listed Inhibitors,Modulators,Libraries in Figure 3B. This was because our pri mary aim was to extract the pathways through which signal perturbation by KN62 and SB203580 influenced the gene expression pattern observed in Figure 4D. As shown in Figure 5C, stimulation of cells with anti IgM led to repression in the activity of MZF1. This inactiva tion, however, was inhibited in the presence of both KN62 and SB203580. Similarly, the anti IgM induced inactivation of Sp1 was also partly inhibited by SB203580, whereas this inactivation was delayed in the presence of KN62.

Somewhat surprisingly, stimulation also resulted in a rapid reduction of the basal activity of NFATc2. Further, while inhibition of p38 had no Inhibitors,Modulators,Libraries significant effect on this process, the inclu sion of KN62 lead to at least a delay in the kinetics of this inactivation. In contrast to these repres sive effects, BCR crosslinking also induced a delayed enhancement in the activities of FOSL1, TBP, NFKB1 and to lesser extent TRP53. However, inhibition of either CaMKII or p38 led to a near Inhibitors,Modulators,Libraries com plete suppression of this activation in the case of FOSL1, TBP, NFKB1, but not of that of TRP53. Thus, in at least four of the seven cases, both inhi selleck inhibitor bitors exerted comparable effects on their anti IgM induced activation profiles. The reasons for the differ ences observed in the remaining three TFs are unclear at the present time. Notwithstanding this however, the results in Figure 5C permitted us to infer that the four similarly affected TFs MZF1, FOSL1, TBP, and NFKB1 could at least partly rationalize the overlapping effects of these two inhibitors on anti IgM stimulated cells, both at the level of gene expression and cell cycle arrest.