Plays a role in RNA-mediated gene silencing by mediating transport of both ingested and endogenous dsRNA between cells. Not required for the uptake of dsRNA from the intestinal lumen. Ubiquitously present in most tissues tested. Expressed in the somatic cells of intestine, muscle, neurons, somatic gonad and embryos but not in the germline (at protein level). Defective in RNA-mediated gene silencing.