The putatively protective Onchocerca volvulus neuronal protein E1 is a member of the death domain protein family.

Here we show that E1, an ankyrin-related, potentially protective, neuronal protein of the human filarial nematode Onchocerca volvulus contains a death domain (DD), most similar to that of human Mort1/FADD (39% identity). In addition, sequence comparison of E1 to its homologue from Litomosoides sigmodontis and to Caenorhabditis elegans ankyrin defines two further putative functional domains. One represents the end of the spectrin-binding domain of ankyrins, the other an unique domain, most highly conserved between these nematodes, containing a calpain sequence motif. Thus, E1 may be involved in apoptosis, raising the possibility that protection against this parasitic helminth may be induced by apoptotic processes.