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A Regulated, Ubiquitin-Independent Degron in I?B?.

ABSTRACT: 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?B? 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?B?'s short half-life. Finally, we show that this degron's activity is regulated by the interaction with NF?B, which controls its solvent exposure, and we demonstrate that this regulation of the degron's activity is critical for I?B?'s signaling functions.

SUBMITTER: Fortmann KT

PROVIDER: S-EPMC4685248 | biostudies-literature | 2015 Aug

REPOSITORIES: biostudies-literature

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A Regulated, Ubiquitin-Independent Degron in IκBα.

Fortmann Karen T KT Lewis Russell D RD Ngo Kim A KA Fagerlund Riku R Hoffmann Alexander A

Journal of molecular biology 20150717 17

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 IκBα 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 seque ...[more]

PMID: 26191773

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