CCDC22 deficiency in humans blunts activation of proinflammatory NF-κB signaling

J Clin Invest. 2013 May;123(5):2244-56. doi: 10.1172/JCI66466. Epub 2013 Apr 8.

Abstract

NF-κB is a master regulator of inflammation and has been implicated in the pathogenesis of immune disorders and cancer. Its regulation involves a variety of steps, including the controlled degradation of inhibitory IκB proteins. In addition, the inactivation of DNA-bound NF-κB is essential for its regulation. This step requires a factor known as copper metabolism Murr1 domain-containing 1 (COMMD1), the prototype member of a conserved gene family. While COMMD proteins have been linked to the ubiquitination pathway, little else is known about other family members. Here we demonstrate that all COMMD proteins bind to CCDC22, a factor recently implicated in X-linked intellectual disability (XLID). We showed that an XLID-associated CCDC22 mutation decreased CCDC22 protein expression and impaired its binding to COMMD proteins. Moreover, some affected individuals displayed ectodermal dysplasia, a congenital condition that can result from developmental NF-κB blockade. Indeed, patient-derived cells demonstrated impaired NF-κB activation due to decreased IκB ubiquitination and degradation. In addition, we found that COMMD8 acted in conjunction with CCDC22 to direct the degradation of IκB proteins. Taken together, our results indicate that CCDC22 participates in NF-κB activation and that its deficiency leads to decreased IκB turnover in humans, highlighting an important regulatory component of this pathway.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / metabolism
  • Carrier Proteins / metabolism*
  • Chromosomes, Human, X
  • Ectodermal Dysplasia / metabolism
  • Gene Expression Regulation*
  • Genetic Linkage
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • I-kappa B Proteins / metabolism
  • Inflammation
  • Microscopy, Fluorescence
  • Mutation
  • NF-KappaB Inhibitor alpha
  • NF-kappa B / metabolism*
  • Neoplasms / metabolism
  • Protein Structure, Tertiary
  • Proteins / metabolism*
  • Signal Transduction*
  • Ubiquitin / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • CCDC22 protein, human
  • COMMD1 protein, human
  • COMMD8 protein, human
  • Carrier Proteins
  • I-kappa B Proteins
  • NF-kappa B
  • NFKBIA protein, human
  • Proteins
  • Ubiquitin
  • NF-KappaB Inhibitor alpha