KLHL7 promotes TUT1 ubiquitination associated with nucleolar integrity: Implications for retinitis pigmentosa

Biochem Biophys Res Commun. 2017 Dec 9;494(1-2):220-226. doi: 10.1016/j.bbrc.2017.10.049. Epub 2017 Oct 12.

Abstract

Kelch-like protein 7 (KLHL7) is a component of Cul3-based Cullin-RING ubiquitin ligase. Recent studies have revealed that mutations in klhl7 gene cause several disorders, such as retinitis pigmentosa (RP). Although KLHL7 is considered to be crucial for regulating the protein homeostasis, little is known about its biological functions. In this study, we report that KLHL7 increases terminal uridylyl transferase 1 (TUT1) ubiquitination involved in nucleolar integrity. TUT1 is normally localized in nucleolus; however, expression of KLHL7 facilitates a vulnerability of nucleolar integrity, followed by a decrease of TUT1 localization in nucleolus. On the other hand, pathogenic KLHL7 mutants, which causes an onset of RP, have little effect on both nucleolar integrity and TUT1 localization. Finally, KLHL7 increases TUT1 ubiquitination levels. Taken together, these results imply that KLHL7 is a novel regulator of nucleolus associated with TUT1 ubiquitination. Our study may provide a valuable information to elucidate a pathogenic mechanism of RP.

Keywords: KLHL7; Nucleolus; Retinitis pigmentosa; TUT1; Ubiquitin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Substitution
  • Autoantigens / genetics
  • Autoantigens / metabolism*
  • Cell Nucleolus / genetics
  • Cell Nucleolus / metabolism*
  • HeLa Cells
  • Humans
  • Mutant Proteins / genetics
  • Mutant Proteins / metabolism
  • Mutation
  • Nuclear Proteins / metabolism
  • Nucleotidyltransferases / genetics
  • Nucleotidyltransferases / metabolism*
  • RNA / genetics
  • RNA / metabolism
  • Recombinant Proteins / genetics
  • Recombinant Proteins / metabolism
  • Retinitis Pigmentosa / etiology*
  • Retinitis Pigmentosa / genetics
  • Retinitis Pigmentosa / metabolism
  • Stress, Physiological
  • Ubiquitination

Substances

  • Autoantigens
  • KLHL7 protein, human
  • Mutant Proteins
  • Nuclear Proteins
  • Recombinant Proteins
  • nucleophosmin
  • RNA
  • Nucleotidyltransferases
  • TUT1 protein, human