LysRS serves as a key signaling molecule in the immune response by regulating gene expression

Mol Cell. 2009 Jun 12;34(5):603-11. doi: 10.1016/j.molcel.2009.05.019.


Lysyl-tRNA synthetase (LysRS) was found to produce diadenosine tetraphosphate (Ap(4)A) in vitro more than two decades ago. Here, we used LysRS silencing in mast cells in combination with transfected normal and mutated LysRS to demonstrate in vivo the critical role played by LysRS in the production of Ap(4)A in response to immunological challenge. Upon such challenge, LysRS was phosphorylated on serine 207 in a MAPK-dependent manner, released from the multisynthetase complex, and translocated into the nucleus. We previously demonstrated that LysRS forms a complex with MITF and its repressor Hint-1, which is released from the complex by its binding to Ap(4)A, enabling MITF to transcribe its target genes. Here, silencing LysRS led to reduced Ap(4)A production in immunologically activated cells, which resulted in a lower level of MITF inducible genes. Our data demonstrate that specific LysRS serine 207 phosphorylation regulates Ap(4)A production in immunologically stimulated mast cells, thus implying that LysRS is a key mediator in gene regulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus
  • Animals
  • Cell Line
  • Dinucleoside Phosphates / biosynthesis
  • Gene Expression Regulation*
  • Humans
  • Immunity, Cellular / genetics*
  • Lysine-tRNA Ligase / metabolism
  • Lysine-tRNA Ligase / physiology*
  • MAP Kinase Signaling System
  • Microphthalmia-Associated Transcription Factor / genetics
  • Microphthalmia-Associated Transcription Factor / metabolism
  • Phosphorylation
  • Rats
  • Serine / metabolism
  • Signal Transduction*


  • Dinucleoside Phosphates
  • MITF protein, human
  • Microphthalmia-Associated Transcription Factor
  • Serine
  • diadenosine tetraphosphate
  • Lysine-tRNA Ligase