Structural Perspective of the Double-Stranded RNA Transport Mechanism by SID-1 Family Proteins.

The systemic RNA interference defective 1 (SID-1) family proteins are putative double-stranded RNA (dsRNA) transporters. Two mammalian homologs, SIDT1 and SIDT2 have been linked to many functions such as innate immune responses, microRNA uptake and lysosomal degradation of RNA/DNA whereas Caenorhabditis elegans SID-1 is essential for systemic RNA interference. However, dsRNA uptake mechanism is largely unknown. In this review, we discuss our current understanding of the molecular functions of SID-1 family proteins at a structure level, which highlights recent structural studies.