Fig. 2.

Blockade of the NF-κB pathway in ABC DLBCL by bortezomib. NF-κB is regulated by members of the IκB family of inhibitors, principally IκBα, which binds to NF-κB dimers and retains them in the cytoplasm. In response to a wide variety of external signals, IκB is phosphorylated by the IKK complex, IκBα is then targeted for ubiquitination and proteasomal degradation. NF-κB is released and translocates to the nucleus, where it activates antiapoptotic and cell-proliferation genes. The stabilization of IκB through proteosome inhibition therefore prevents NF-κB activation.