Excitingly, we found two remorin proteins to co-purify with transmissible virus (Table 3) . Consistent with remorin localization in plant cell membranes [73] , peptides derived from remorin were never detected from aphid homogenates (data not shown). Remorins are plant-specific proteins with unknown functions [74] but have been receiving wide attention because of their involvement in plant defense against viral, bacterial, and rhizobial infections [reviewed in [75] ]. In vivo, remorins cluster in the plasma membrane within PD and lipid rafts [73] . Remorin proteins accumulate in mature and aging tissues and in source tissue [76] where mature, branched PD are in the majority. Remorin can physically interact with the PVX movement protein TRIPLE GENE BLOCK PROTEIN 1. Remorin association with PVX is inversely proportional to the ability of PVX to move from cell-to-cell [73] . These data show that remorin proteins may function in vivo to retain virus within individual cells. Remorin association with luteovirids is particularly interesting because the luteovirid RTP retains virus in the phloem. Phloem-retention of luteovirids is critical for virus dispersal by aphids [13] . How this occurs is not known, but one possibility could be via protein-protein interactions between the C-terminal domain of the RTP and remorin. Luteovirid mutants that are no longer restricted to the phloem [13] will be particularly useful to probe direct interactions with remorin proteins.