The E3 ubiquitin ligase TRIM11 mediates the degradation of congenital central hypoventilation syndrome-associated polyalanine-expanded PHOX2B

Sara Parodi, Eleonora Di Zanni, Simona Di Lascio, Paola Bocca, Ignazia Prigione, Diego Fornasari, Maria Pennuto, Tiziana Bachetti, Isabella Ceccherini

Research output: Contribution to journalArticle

Abstract

Expansions of a polyalanine (polyA) stretch in the coding region of the PHOX2B gene cause congenital central hypoventilation syndrome (CCHS), a neurocristopathy characterized by the absence of adequate control of autonomic breathing. Expansion of polyA in PHOX2B leads to protein misfolding and accumulation into inclusions. The mechanisms that regulate mutant protein degradation and turnover have been poorly elucidated. Here, we investigate the regulation of degradation of wild-type and polyA-expanded PHOX2B. We show that expanded PHOX2B is targeted for degradation through the ubiquitin-proteasome system, resulting in lowered levels of the mutant protein relative to its wild-type counterpart. Moreover, we show that mutant PHOX2B forms ubiquitinpositive inclusions, which sequester wild-type PHOX2B. This sequestration correlates with reduced transcriptional activity of endogenous wild-type protein in neuroblastoma cells. Finally, we show that the E3 ubiquitin ligase TRIM11 plays a critical role in the clearance of mutant PHOX2B through the proteasome. Importantly, clearance of mutant PHOX2B by TRIM11 correlates with a rescue of PHOX2B transcriptional activity. We propose that CCHS is partially caused by a dominant-negative effect of expanded PHOX2B due to the retention of the wild-type protein in pathogenic aggregates. Our results demonstrate that TRIM11 is a novel modifier of mutant PHOX2B toxicity and represents a potential therapeutic target for CCHS.

Original languageEnglish
Pages (from-to)1025-1035
Number of pages11
JournalJournal of Molecular Medicine
Volume90
Issue number9
DOIs
Publication statusPublished - Sep 2012

Keywords

  • Aggregation
  • Congenital central hypoventilation syndrome
  • E3 ubiquitin ligase
  • Insoluble fraction
  • PHOX2B
  • Polyalanine expansion
  • Ubiquitin-proteasome system

ASJC Scopus subject areas

  • Molecular Medicine
  • Drug Discovery
  • Genetics(clinical)

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