Crosstalk between ERK2 and RXR regulates nuclear import of transcription factor NGFI-B

Biochem Biophys Res Commun. 2005 Oct 21;336(2):646-52. doi: 10.1016/j.bbrc.2005.08.143.

Abstract

Transcription factor NGFI-B initiates apoptosis when allowed to translocate to mitochondria. Retinoid-X receptor (RXR), another member of the nuclear receptor family, regulates NGFI-B signaling through heterodimerization and nuclear export. Growth factor EGF activates ERK2, which phosphorylates NGFI-B and determines if NGFI-B is allowed to translocate to mitochondria. In the present study, EGF treatment resulted in an increased nuclear import of NGFI-B. Likewise, active ERK2 resulted in a preferential nuclear localization of NGFI-B. When coexpressed with RXR the nuclear import and nuclear localization induced by active ERK2 were strongly reduced. In the presence of its ligand 9-cis-retinoic acid, RXR no longer inhibited ERK2-induced nuclear import. Thus, RXR serves a permissive role for ERK2-mediated nuclear accumulation of NGFI-B. This finding represents a novel crosstalk between ERK2 and RXR signaling pathways, and explains how two independent inhibitors of apoptosis (EGF and 9-cis-retinoic acid) may cooperate to regulate nuclear targeting of apoptosis inducer NGFI-B.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus / physiology*
  • Animals
  • Cell Line
  • Cell Nucleus / metabolism*
  • Chlorocebus aethiops
  • Kidney / metabolism*
  • Mitogen-Activated Protein Kinase 1 / metabolism*
  • Retinoid X Receptors / metabolism*
  • Signal Transduction / physiology*
  • Transcription Factors / metabolism*

Substances

  • Retinoid X Receptors
  • Transcription Factors
  • Mitogen-Activated Protein Kinase 1