The interaction between tobacco mosaic virus and its host plant cells has been intensively studied as a model for macromolecular trafficking. The observation that GFP-labelled TMV movement protein localises to microtubules led to the suggestion that microtubules are required for the cell to cell movement of the virus. In a recent paper we have demonstrated that the targeting of TMV movement protein to plasmodesmata requires the actin and ER networks, which supports previous evidence from our laboratory that showed that disruption of microtubules did not prevent cell to cell movement of TMV virus, and that a mutated movement protein, which did not localise to micro-tubules, showed enhanced viral movement. In this addendum we speculate where the TMV movement protein accumulates within plasmodesmata, and the relationship of this accumulation to the cell to cell movement of the virus.