A Regulated, Ubiquitin-Independent Degron in I kappa B alpha

作者：Fortmann Karen T; Lewis Russell D; Ngo Kim A; Fagerlund Riku; Hoffmann Alexander^*

来源：Journal of Molecular Biology, 2015, 427(17): 2748-2756.

DOI：10.1016/j.jmb.2015.07.008

• protein half-life control
• degron
• ubiquitin-independent degradation
• NF kappa B
• I kappa B alpha

Whereas ubiquitin-dependent degrons have been characterized in some detail, how proteins may be targeted to ubiquitin-independent proteasomal degradation remains unclear. Here we show that I kappa B alpha contains an ubiquitin-independent degron whose activity is portable to heterologous proteins such as the globular protein GFP (green fluorescent protein) via a proteasome-dependent, ubiquitin-independent, non-lysosomal pathway. The ubiquitin-independent degradation signal resides in an 11-amino-acid sequence, which is not only sufficient but also required for I kappa B alpha's short half-life. Finally, we show that this degron's activity is regulated by the interaction with NF kappa B, which controls its solvent exposure, and we demonstrate that this regulation of the degron's activity is critical for I kappa B alpha's signaling functions.

• 出版日期2015-8-28