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

D Cheishvili, C Maayan, R Cohen-Kupiec… - Human molecular …, 2011 - academic.oup.com
D Cheishvili, C Maayan, R Cohen-Kupiec, S Lefler, M Weil, G Ast, A Razin
Human molecular genetics, 2011academic.oup.com
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 …
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.
Oxford University Press