Bcl-3 signaling cascade. Diverse cytokines activate an IKK or IKK-related kinase to induce processing of the p105 precursor to p50, which in turn dimerizes and binds Bcl-3. Bcl-3 is regulated by phosphorylation and ubiquitination, both of which have a positive effect on its function. CYLD deubiquitinates Bcl-3 and prevents its nuclear translocation and GSK3. Bcl-3 is also phosphorylated by GSK3, which delays its degradation by the proteosomal pathway. Nuclear Bcl-3 can both induce and repress expression of a diverse array of genes.