Shared pathways of IkappaB kinase-induced SCF(betaTrCP)-mediated ubiquitination and degradation for the NF-kappaB precursor p105 and IkappaBalpha.

ABSTRACT: p105 (NFKB1) acts in a dual way as a cytoplasmic IkappaB molecule and as the source of the NF-kappaB p50 subunit upon processing. p105 can form various heterodimers with other NF-kappaB subunits, including its own processing product, p50, and these complexes are signal responsive. Signaling through the IkappaB kinase (IKK) complex invokes p105 degradation and p50 homodimer formation, involving p105 phosphorylation at a C-terminal destruction box. We show here that IKKbeta phosphorylation of p105 is direct and does not require kinases downstream of IKK. p105 contains an IKK docking site located in a death domain, which is separate from the substrate site. The substrate residues were identified as serines 923 and 927, the latter of which was previously assumed to be a threonine. S927 is part

SUBMITTER: Heissmeyer V 

PROVIDER: S-EPMC99557 | biostudies-literature | 2001 Feb

REPOSITORIES: biostudies-literature