CD40 regulates the processing of NF-kappaB2 p100 to p52

EMBO J. 2002 Oct 15;21(20):5375-85. doi: 10.1093/emboj/cdf542.

Abstract

The nf-kb2 gene encodes the cytoplasmic NF-kappaB inhibitory protein p100 from which the active p52 NF-kappaB subunit is derived by proteasome-mediated proteolysis. Ligands which stimulate p100 processing to p52 have not been defined. Here, ligation of CD40 on transfected 293 cells is shown to trigger p52 production by stimulating p100 ubiquitylation and subsequent proteasome-mediated proteolysis. CD40-mediated p52 accumulation is dependent on de novo protein synthesis and triggers p52 translocation into the nucleus to generate active NF-kappaB dimers. Endogenous CD40 ligation on primary murine splenic B cells also stimulates p100 processing, which results in the delayed nuclear translocation of p52-RelB dimers. In both 293 cells and primary splenic B cells, the ability of CD40 to trigger p100 processing requires functional NF-kappaB-inducing kinase (NIK). In contrast, NIK activity is not required for CD40 to stimulate the degradation of IkappaBalpha in either cell type. The regulation of p100 processing by CD40 is likely to be important for the transcriptional regulation of CD40 target genes in adaptive immune responses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Animals
  • B-Lymphocytes / immunology
  • B-Lymphocytes / metabolism
  • CD40 Antigens / metabolism*
  • Cell Line
  • Cycloheximide / pharmacology
  • Cysteine Endopeptidases / metabolism
  • DNA-Binding Proteins / metabolism
  • Humans
  • I-kappa B Proteins*
  • Ligands
  • Mice
  • Multienzyme Complexes / metabolism
  • NF-KappaB Inhibitor alpha
  • NF-kappa B / genetics
  • NF-kappa B / metabolism*
  • NF-kappa B p50 Subunit
  • NF-kappa B p52 Subunit
  • NF-kappaB-Inducing Kinase
  • Proteasome Endopeptidase Complex
  • Protein Processing, Post-Translational
  • Protein Serine-Threonine Kinases / metabolism
  • Protein Synthesis Inhibitors / pharmacology
  • Proto-Oncogene Proteins / metabolism
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Transcription Factor RelB
  • Transcription Factors / metabolism
  • Transfection
  • Ubiquitin / metabolism

Substances

  • CD40 Antigens
  • DNA-Binding Proteins
  • I-kappa B Proteins
  • Ligands
  • Multienzyme Complexes
  • NF-kappa B
  • NF-kappa B p50 Subunit
  • NF-kappa B p52 Subunit
  • NFKBIA protein, human
  • Nfkbia protein, mouse
  • Protein Synthesis Inhibitors
  • Proto-Oncogene Proteins
  • RELB protein, human
  • Recombinant Proteins
  • Relb protein, mouse
  • Transcription Factors
  • Ubiquitin
  • NF-KappaB Inhibitor alpha
  • Transcription Factor RelB
  • Cycloheximide
  • Protein Serine-Threonine Kinases
  • Cysteine Endopeptidases
  • Proteasome Endopeptidase Complex