NFKB1 and systemic lupus erythematosus: Finally, by using kinase inhibitor (BAY) and proteosome degradation inhibitor (LAC), we found that in both lupus and normal B cells, CD40-induced degradation of IκBα was blocked by both IκB phosphorylation and proteosome degradation inhibitors, whereas CD40-induced phosphorylation of IκBα and P65 were blocked only by IκB phosphorylation inhibitor (Fig. 6), suggesting CD40-induced NF-κB activation depends on both IκB phosphorylation and proteosome degradation.