TI - LPS partially degrades IkappaB-alpha . AB - It has been well documented that NF-kappaB associated with IkappaB resides in cytoplasm as an inactive form . On the process of NF-kappaB activation , IkappaBalpha is rapidly PHOSphorylated and degraded and then free NF-kappaB is translocated to nucleus [19] . In order to investigate whether LPS is able to activate NF-kappaB via intracellular TLR4 , we examined degradation of IkappaB-alpha in NB-1 cells treated with LPS ( 100 ng/ml ) for various time . As shown in Fig. 4 , the expression of IkappaB-alpha partially decreased up to 30 min after LPS treatment and it returned to the original state 45 and 60 min after LPS treatment . The possibility that a small amount of contaminants in the LPS preparation might induce the partial activation still remained .