Involvement of IKAP in peripheral target innervation and in specific JNK and NGF signaling in developing PNS neurons

PLoS One. 2014 Nov 19;9(11):e113428. doi: 10.1371/journal.pone.0113428. eCollection 2014.

Abstract

A splicing mutation in the ikbkap gene causes Familial Dysautonomia (FD), affecting the IKAP protein expression levels and proper development and function of the peripheral nervous system (PNS). Here we attempted to elucidate the role of IKAP in PNS development in the chick embryo and found that IKAP is required for proper axonal outgrowth, branching, and peripheral target innervation. Moreover, we demonstrate that IKAP colocalizes with activated JNK (pJNK), dynein, and β-tubulin at the axon terminals of dorsal root ganglia (DRG) neurons, and may be involved in transport of specific target derived signals required for transcription of JNK and NGF responsive genes in the nucleus. These results suggest the novel role of IKAP in neuronal transport and specific signaling mediated transcription, and provide, for the first time, the basis for a molecular mechanism behind the FD phenotype.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Axons / metabolism
  • Carrier Proteins / antagonists & inhibitors
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cell Movement
  • Cells, Cultured
  • Chick Embryo
  • Chickens
  • Dyneins / metabolism
  • Dysautonomia, Familial / genetics
  • Dysautonomia, Familial / pathology
  • Ganglia, Spinal / cytology
  • JNK Mitogen-Activated Protein Kinases / metabolism*
  • Microscopy, Fluorescence
  • Nerve Growth Factor / metabolism*
  • Neurons / cytology
  • Neurons / metabolism
  • Peripheral Nervous System / growth & development
  • Peripheral Nervous System / pathology*
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Signal Transduction
  • Tubulin / chemistry
  • Tubulin / metabolism

Substances

  • Carrier Proteins
  • RNA, Small Interfering
  • Tubulin
  • Nerve Growth Factor
  • JNK Mitogen-Activated Protein Kinases
  • Dyneins

Grants and funding

This study was supported by the FD research consortium (FD Hope, FD Foundation Inc., FD Israel Foundation) and by the Israel Science Foundation (ISF grant 1491/09). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.