Moreover, NF-κB activation induced by PKK was not inhibited by dominant negative Bimp1 and proceeded in the absence of Bcl10, two components of a recently described PKC signaling pathway.
These C-terminal domains mediate recruitment of RIP and RICK to upstream signaling components, whereas the IM regions link these kinases to the common regulator IKK (9-13).These trigger molecules interact with surface receptors or specific intracellular sensors that lead to the activation of NF-κB through signal-specific mediators and common downstream effectors such as IκBα and IκB kinase (IKK) (1, 2).RICK and RIP are highly related kinases that mediate NF-κB activation in the Nod1 (or Nod2) and TNFR1 (or TRAIL) receptor signaling pathways, respectively (3-8).Recent studies have identified a PKC-dependent signaling pathway of NF-κB activation that is mediated by Bcl10 (17-19).Bimps and MALT1 appear to link PKC activation induced by surface receptors to Bcl10 and IKKs (17,20).Protein kinase C-associated kinase (PKK) is a recently described kinase of unknown function that was identified on the basis of its specific interaction with PKCβ.
PKK contains N-terminal kinase and C-terminal ankyrin repeats domains linked to an intermediate region.
Phosphorylation of site 5 by casein kinase II creates this recognition site.
Thereafter, each successive phosphorylation introduced by GSK-3 generates a new recognition site.
Inhibition of NF-κB activation by dominant negative PKK was reverted by co-expression of PKCβI, suggesting a functional association between PKK and PKCβI.
PKK-mediated NF-κB activation required IKKα and IKKβ but not IKKγ, the regulatory subunit of the IKK complex.
is a transcription factor that mediates the activation of a large array of target genes that are involved in the regulation of diverse functions including inflammation, cell proliferation, and survival (1).