L-periaxin interacts with S-periaxin through its PDZ domain

Periaxin was first identified as a protein in myelinating Schwann cells through a screen of novel cytoskeleton-associated proteins in peripheral nerve myelination. The periaxin gene encodes two isoforms, namely, L- and S-periaxin, which are 1461 and 147 residues in size, respectively. Several loss-of-function mutations linked to autosomal recessive Dejerine-Sottas neuropathy and demyelinating Charcot-Marie-Tooth disease in periaxin have been described. In this study, the colocolization of L- and S-periaxin in the cytoplasm of RSC96 cells was found by immunofluorescence assays. The interaction between these two isoforms was confirmed by co-immunoprecipitation, fluorescence complementation experiment, and GST pull-down assay. Results also showed that the two periaxin isoforms interacted in the cytoplasm through the PDZ domain, and their interaction prevented the homodimerization of L-periaxin. S-periaxin may regulate the function of L-periaxin in Schwann cells.