TAp63γ demethylation regulates protein stability and cellular distribution during neural stem cell differentiation

PLoS One. 2012;7(12):e52417. doi: 10.1371/journal.pone.0052417. Epub 2012 Dec 14.

Abstract

p63 is a close relative of the p53 tumor suppressor and transcription factor that modulates cell fate. The full-length isoform of p63, containing a transactivation (TA) domain (TAp63) is an essential proapoptotic protein in neural development. The role of p63 in epithelial development is also well established; however, its precise function during neural differentiation remains largely controversial. Recently, it has been demonstrated that several conserved elements of apoptosis are also integral components of cellular differentiation; p53 directly interacts with key regulators of neurogenesis. The aim of this study was to evaluate the role of p63 during mouse neural stem cell (NSC) differentiation and test whether the histone H3 lysine 27-specific demethylase JMJD3 interacts with p63 to redirect NSCs to neurogenesis. Our results showed that JMJD3 and TAp63γ are coordinately regulated to establish neural-specific gene expression programs in NSCs undergoing differentiation. JMJD3 overexpression increased TAp63γ levels in a demethylase activity-dependent manner. Importantly, overexpression of TAp63γ increased β-III tubulin whereas downregulation of TAp63γ by specific p63 siRNA decreased β-III tubulin. Immunoprecipitation assays demonstrated direct interaction between TAp63γ and JMJD3, and modulation of TAp63γ methylation status by JMJD3-demethylase activity. Importantly, the demethylase activity of JMJD3 influenced TAp63γ protein stabilization and cellular distribution, as well as TAp63γ-regulated neurogenesis. These findings clarify the role of p63 in adult neural progenitor cells and reveal TAp63γ as a direct target for JMJD3-mediated neuronal commitment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Differentiation / genetics
  • Cell Line
  • Cell Nucleus / genetics
  • Cell Nucleus / metabolism
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Gene Expression Regulation, Developmental
  • Genes, Tumor Suppressor
  • Jumonji Domain-Containing Histone Demethylases / genetics
  • Jumonji Domain-Containing Histone Demethylases / metabolism
  • Methylation
  • Mice
  • Neural Stem Cells / cytology*
  • Neural Stem Cells / metabolism*
  • Neurogenesis
  • Neurons / metabolism
  • Neurons / physiology
  • Phosphoproteins / genetics*
  • Phosphoproteins / metabolism*
  • Protein Interaction Domains and Motifs / genetics
  • Protein Stability
  • Trans-Activators / genetics*
  • Trans-Activators / metabolism*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism

Substances

  • DNA-Binding Proteins
  • Phosphoproteins
  • Trans-Activators
  • Transcription Factors
  • Trp63 protein, mouse
  • Tumor Suppressor Proteins
  • Jumonji Domain-Containing Histone Demethylases
  • Kdm6b protein, mouse

Grants and funding

This work was supported by grants PTDC/SAU-NMC/117877/2010 and Pest-OE/SAU/UI4013/2011, and fellowships SFRH/BD/43959/2008 (M.B.F.) and SFRH/BPD/34603/2007 (A.F.N.) from Fundação para a Ciência e a Tecnologia, Portugal. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.