Stress-induced TRBP phosphorylation enhances its interaction with PKR to regulate cellular survival

Sci Rep. 2018 Jan 18;8(1):1020. doi: 10.1038/s41598-018-19360-8.

Abstract

Transactivation response element RNA-binding protein (TRBP or TARBP2) initially identified to play an important role in human immunodeficiency virus (HIV) replication also has emerged as a regulator of microRNA biogenesis. In addition, TRBP functions in signaling pathways by negatively regulating the interferon-induced double-stranded RNA (dsRNA)-activated protein kinase (PKR) during viral infections and cell stress. During cellular stress, PKR is activated and phosphorylates the α subunit of the eukaryotic translation factor eIF2, leading to the cessation of general protein synthesis. TRBP inhibits PKR activity by direct interaction as well as by binding to PKR's two known activators, dsRNA and PACT, thus preventing their interaction with PKR. In this study, we demonstrate for the first time that TRBP is phosphorylated in response to oxidative stress and upon phosphorylation, inhibits PKR more efficiently promoting cell survival. These results establish that PKR regulation through stress-induced TRBP phosphorylation is an important mechanism ensuring cellular recovery and preventing apoptosis due to sustained PKR activation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Apoptosis
  • Cell Line, Tumor
  • Cell Survival
  • Humans
  • Immunoprecipitation
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Membrane Potential, Mitochondrial
  • Oxidative Stress
  • Phosphorylation
  • Protein Binding
  • Protein Interaction Mapping / methods
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Stress, Physiological*
  • Two-Hybrid System Techniques
  • eIF-2 Kinase / metabolism*

Substances

  • RNA-Binding Proteins
  • trans-activation responsive RNA-binding protein
  • EIF2AK2 protein, human
  • eIF-2 Kinase
  • JNK Mitogen-Activated Protein Kinases