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PLoS Genet. 2019 Mar 15;15(3):e1008057. doi: 10.1371/journal.pgen.1008057. eCollection 2019 Mar.

Cellular response to small molecules that selectively stall protein synthesis by the ribosome.

Author information

1
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California, United States of America.
2
Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA, United States of America.
3
Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA, United States of America.
4
California Institute for Quantitative Biomedical Research, University of California, San Francisco, San Francisco, CA, United States of America.
5
Department of Urology, University of California, San Francisco, San Francisco, CA, United States of America.
6
Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, United States of America.
7
Department of Chemistry, University of California, Berkeley, Berkeley, California, United States of America.
8
QB3 Institute, University of California, Berkeley, Berkeley, California, United States of America.
9
Molecular Biophysics and Integrated Bio-imaging, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America.

Abstract

Identifying small molecules that inhibit protein synthesis by selectively stalling the ribosome constitutes a new strategy for therapeutic development. Compounds that inhibit the translation of PCSK9, a major regulator of low-density lipoprotein cholesterol, have been identified that reduce LDL cholesterol in preclinical models and that affect the translation of only a few off-target proteins. Although some of these compounds hold potential for future therapeutic development, it is not known how they impact the physiology of cells or ribosome quality control pathways. Here we used a genome-wide CRISPRi screen to identify proteins and pathways that modulate cell growth in the presence of high doses of a selective PCSK9 translational inhibitor, PF-06378503 (PF8503). The two most potent genetic modifiers of cell fitness in the presence of PF8503, the ubiquitin binding protein ASCC2 and helicase ASCC3, bind to the ribosome and protect cells from toxic effects of high concentrations of the compound. Surprisingly, translation quality control proteins Pelota (PELO) and HBS1L sensitize cells to PF8503 treatment. In genetic interaction experiments, ASCC3 acts together with ASCC2, and functions downstream of HBS1L. Taken together, these results identify new connections between ribosome quality control pathways, and provide new insights into the selectivity of compounds that stall human translation that will aid the development of next-generation selective translation stalling compounds to treat disease.

PMID:
30875366
PMCID:
PMC6436758
DOI:
10.1371/journal.pgen.1008057
[Indexed for MEDLINE]
Free PMC Article

Conflict of interest statement

The authors have declared that no competing interests exist.

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