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Citation
Tags
HERO ID
7077091
Reference Type
Journal Article
Title
The Ubiquitin Proteasome System Is a Key Regulator of Pluripotent Stem Cell Survival and Motor Neuron Differentiation
Author(s)
Bax, M; Poronnik, P; Yerbury, JJ; Saunders, DN; Ooi, L; Mckenna, J; Do-Ha, D; Stevens, CH; Higginbottom, S; Balez, R; Cabral-Da-Silva, MEC; Farrawell, NE; Engel, M; ,
Year
2019
Publisher
MDPI
Location
BASEL
PMID
31200561
DOI
10.3390/cells8060581
Web of Science Id
WOS:000475309200069
Abstract
The ubiquitin proteasome system (UPS) plays an important role in regulating numerous cellular processes, and a dysfunctional UPS is thought to contribute to motor neuron disease. Consequently, we sought to map the changing ubiquitome in human iPSCs during their pluripotent stage and following differentiation to motor neurons. Ubiquitinomics analysis identified that spliceosomal and ribosomal proteins were more ubiquitylated in pluripotent stem cells, whilst proteins involved in fatty acid metabolism and the cytoskeleton were specifically ubiquitylated in the motor neurons. The UPS regulator, ubiquitin-like modifier activating enzyme 1 (UBA1), was increased 36-fold in the ubiquitome of motor neurons compared to pluripotent stem cells. Thus, we further investigated the functional consequences of inhibiting the UPS and UBA1 on motor neurons. The proteasome inhibitor MG132, or the UBA1-specific inhibitor PYR41, significantly decreased the viability of motor neurons. Consistent with a role of the UPS in maintaining the cytoskeleton and regulating motor neuron differentiation, UBA1 inhibition also reduced neurite length. Pluripotent stem cells were extremely sensitive to MG132, showing toxicity at nanomolar concentrations. The motor neurons were more resilient to MG132 than pluripotent stem cells but demonstrated higher sensitivity than fibroblasts. Together, this data highlights the important regulatory role of the UPS in pluripotent stem cell survival and motor neuron differentiation.
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