Fig. 2.

Selective inhibition of β1i, β5i or both using UK-101 or LKS01 does not block TNFα-stimulated phosphorylation and degradation of IκBα. (A) In H23 cells pretreated with vehicle (DMSO), TNFα (15 ng/ml) was able to stimulate phosphorylation and subsequent degradation of IκBα when monitored by immunoblotting over 90 min. However, the expoxomicin pretreatment almost completely abolished TNFα-stimulated degradation of IκBα. (B) Pretreatment with UK-101 (1 μM) or LKS01 (0.2 μM), either individually or in combination, did not have a negative impact on TNFα-stimulated phosphorylation and degradation of IκBα. Densitometric analyses were performed to quantify the intensities of IκBα and β-actin bands, and the calculated extent of IκBα degradation is shown in bar graphs.