IKAP/Elp1 involvement in cytoskeleton regulation and implication for familial dysautonomia

Hum Mol Genet. 2011 Apr 15;20(8):1585-94. doi: 10.1093/hmg/ddr036. Epub 2011 Jan 27.

Abstract

Deficiency in the IKAP/Elp1 protein leads to the recessive sensory autosomal congenital neuropathy which is called familial dysautonomia (FD). This protein was originally identified as a role player in transcriptional elongation being a subunit of the RNAPII transcriptional Elongator multi-protein complex. Subsequently, IKAP/Elp1 was shown to play various functions in the cytoplasm. Here, we describe experiments performed with IKAP/Elp1 downregulated cell lines and FD-derived cells and tissues. Immunostaining of the cytoskeleton component α-tubulin in IKAP/Elp1 downregulated cells revealed disorganization of the microtubules (MTs) that was reflected in aberrant cell shape and process formation. In contrast to a recent report on the decrease in α-tubulin acetylation in IKAP/Elp1 downregulated cells, we were unable to observe any effect of IKAP/Elp1 deficiency on α-tubulin acetylation in the FD cerebrum and in a variety of IKAP/Elp1 downregulated cell lines. To explore possible candidates involved in the observed aberrations in MTs, we focused on superior cervical ganglion-10 protein (SCG10), also called STMN2, which is known to be an MT destabilizing protein. We have found that SCG10 is upregulated in the IKAP/Elp1-deficient FD cerebrum, FD fibroblasts and in IKAP/Elp1 downregulated neuroblastoma cell line. To better understand the effect of IKAP/Elp1 deficiency on SCG10 expression, we investigated the possible involvement of RE-1-silencing transcription factor (REST), a known repressor of the SCG10 gene. Indeed, REST was downregulated in the IKAP/Elp1-deficient FD cerebrum and IKAP/Elp1 downregulated neuroblastoma cell line. These results could shed light on a possible link between IKAP/Elp1 deficiency and cytoskeleton destabilization.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylation
  • Carrier Proteins / genetics*
  • Case-Control Studies
  • Cell Adhesion
  • Cell Line, Tumor
  • Cell Shape
  • Cerebrum / metabolism
  • Child
  • Dysautonomia, Familial / metabolism
  • Dysautonomia, Familial / pathology*
  • Female
  • Fibroblasts / cytology
  • Fibroblasts / metabolism
  • Histone Acetyltransferases / metabolism
  • Humans
  • Male
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Microtubules / metabolism*
  • Middle Aged
  • Nerve Tissue Proteins / metabolism
  • Neurites / metabolism
  • RNA Interference
  • Repressor Proteins / metabolism
  • Stathmin
  • Transcriptional Elongation Factors
  • Tubulin / metabolism
  • Up-Regulation

Substances

  • Carrier Proteins
  • Elp1 protein, human
  • Membrane Proteins
  • Nerve Tissue Proteins
  • RE1-silencing transcription factor
  • Repressor Proteins
  • STMN2 protein, human
  • Stathmin
  • Transcriptional Elongation Factors
  • Tubulin
  • ELP3 protein, human
  • Histone Acetyltransferases