Uev1A amino terminus stimulates poly-ubiquitin chain assembly and is required for NF-κB activation

Cell Signal. 2020 Oct:74:109712. doi: 10.1016/j.cellsig.2020.109712. Epub 2020 Jul 11.

Abstract

The ubiquitin (Ub)-conjugating enzyme variants (Uev) Uev1A and Mms2 interact with Ubc13 to form heterodimeric complexes with different biological functions. Uev1A-Ubc13 is involved in NF-κB activation while Mms2-Ubc13 is required for the DNA-damage response. The structural comparison of the core domains of these two Uevs reveals no obvious difference, suggesting that the amino terminal extension of Uev1A plays a critical role in the functional determination. Indeed, truncated Uev1A lacking the N-terminal extension behaves like Mms2, while a chimeric protein containing the N-terminal Uev1A fused to Mms2 functionally resembles Uev1A. Interestingly, the N-terminal extension of Uev1A also dictates whether to assemble di- or poly-Ub chains in an in vitro reaction. Both thermodynamic measurements and enzymatic assays revealed that the Uev1A N-terminal extension weakens the Uev-Ubc13 interaction; however, other means capable of causing a reduced Uev1A-Ubc13 affinity and poly-Ub chain assembly do not necessarily promote NF-κB activation, indicating that the poly-Ub chain formation is not the only component contributed by the N-terminal extension of Uev1A. The physiological relevance of the Uev1A N-terminal truncation is presented and discussed.

Keywords: DNA-damage response; Mms2; NF-κB signaling; Poly-ubiquitination; Ubc13; Uev1A.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Cell Line, Tumor
  • Gene Expression Regulation
  • Humans
  • NF-kappa B / metabolism*
  • Protein Binding
  • Transcription Factors / metabolism*
  • Ubiquitin-Conjugating Enzymes / metabolism*

Substances

  • NF-kappa B
  • Transcription Factors
  • UBE2N protein, human
  • UBE2V1 protein, human
  • UBE2V2 protein, human
  • Ubiquitin-Conjugating Enzymes