The WD40-repeat protein WDR-48 promotes the stability of the deubiquitinating enzyme USP-46 by inhibiting its ubiquitination and degradation.
J Biol Chem
; 295(33): 11776-11788, 2020 08 14.
Article
em En
| MEDLINE
| ID: mdl-32587090
ABSTRACT
Ubiquitination is a reversible post-translational modification that has emerged as a critical regulator of synapse development and function. However, the mechanisms that regulate the deubiquitinating enzymes (DUBs) responsible for the removal of ubiquitin from target proteins are poorly understood. We have previously shown that the DUB ubiquitin-specific protease 46 (USP-46) removes ubiquitin from the glutamate receptor GLR-1 and regulates its trafficking and degradation in Caenorhabditis elegans We found that the WD40-repeat proteins WDR-20 and WDR-48 bind and stimulate the catalytic activity of USP-46. Here, we identified another mechanism by which WDR-48 regulates USP-46. We found that increased expression of WDR-48, but not WDR-20, promotes USP-46 abundance in mammalian cells in culture and in C. elegans neurons in vivo Inhibition of the proteasome increased USP-46 abundance, and this effect was nonadditive with increased WDR-48 expression. We found that USP-46 is ubiquitinated and that expression of WDR-48 reduces the levels of ubiquitin-USP-46 conjugates and increases the t1/2 of USP-46. A point-mutated WDR-48 variant that disrupts binding to USP-46 was unable to promote USP-46 abundance in vivo Finally, siRNA-mediated knockdown of wdr48 destabilizes USP46 in mammalian cells. Together, these results support a model in which WDR-48 binds and stabilizes USP-46 protein levels by preventing the ubiquitination and degradation of USP-46 in the proteasome. Given that a large number of USPs interact with WDR proteins, we propose that stabilization of DUBs by their interacting WDR proteins may be a conserved and widely used mechanism that controls DUB availability and function.
Palavras-chave
Caenorhabditis elegans (C. elegans); USP-12; USP-46; WD40-repeat; WDR; WDR48; cell biology; deubiquitinating enzyme (DUB); neurobiology; post-translational modification; post-translational modification (PTM); proteasome; protein degradation; protein homeostasis; regulation; ubiquitin; ubiquitin-specific peptidase 46
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Base de dados:
MEDLINE
Assunto principal:
Caenorhabditis elegans
Limite:
Animals
/
Humans
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article