UCHL3 Regulates Topoisomerase-Induced Chromosomal Break Repair by Controlling TDP1 Proteostasis

Cell Rep. 2018 Jun 12;23(11):3352-3365. doi: 10.1016/j.celrep.2018.05.033.

Abstract

Genomic damage can feature DNA-protein crosslinks whereby their acute accumulation is utilized to treat cancer and progressive accumulation causes neurodegeneration. This is typified by tyrosyl DNA phosphodiesterase 1 (TDP1), which repairs topoisomerase-mediated chromosomal breaks. Although TDP1 levels vary in multiple clinical settings, the mechanism underpinning this variation is unknown. We reveal that TDP1 is controlled by ubiquitylation and identify UCHL3 as the deubiquitylase that controls TDP1 proteostasis. Depletion of UCHL3 increases TDP1 ubiquitylation and turnover rate and sensitizes cells to TOP1 poisons. Overexpression of UCHL3, but not a catalytically inactive mutant, suppresses TDP1 ubiquitylation and turnover rate. TDP1 overexpression in the topoisomerase therapy-resistant rhabdomyosarcoma is driven by UCHL3 overexpression. In contrast, UCHL3 is downregulated in spinocerebellar ataxia with axonal neuropathy (SCAN1), causing elevated levels of TDP1 ubiquitylation and faster turnover rate. These data establish UCHL3 as a regulator of TDP1 proteostasis and, consequently, a fine-tuner of protein-linked DNA break repair.

Keywords: SCAN1; TDP; UCHL3; aging; cancer; heart failure; myocardial infarction; neurodegeneration; rhabdosarcoma; topoisomerase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Chromosome Breakage
  • Cysteine Endopeptidases / chemistry
  • Cysteine Endopeptidases / genetics
  • Cysteine Endopeptidases / metabolism*
  • DNA Repair*
  • DNA Topoisomerases, Type I / metabolism*
  • Down-Regulation
  • HEK293 Cells
  • Humans
  • Nucleotidases / metabolism
  • Phosphoric Diester Hydrolases / genetics
  • Phosphoric Diester Hydrolases / metabolism*
  • Proteostasis
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Ubiquitin / metabolism
  • Ubiquitin Thiolesterase
  • Ubiquitination
  • Up-Regulation

Substances

  • RNA, Small Interfering
  • Ubiquitin
  • CANT1 protein, human
  • Nucleotidases
  • Phosphoric Diester Hydrolases
  • TDP1 protein, human
  • UCHL3 protein, human
  • Ubiquitin Thiolesterase
  • Cysteine Endopeptidases
  • DNA Topoisomerases, Type I