Proteomic analysis of the plasma membrane-movement tubule complex of cowpea mosaic virus

Cowpea mosaic virus forms tubules constructed from the movement protein (MP) in plasmodesmata (PD) to achieve cell-to-cell movement of its virions. Similar tubules, delineated by the plasma membrane (PM), are formed protruding from the surface of infected protoplasts. These PM-tubule complexes were isolated from protoplasts by immunoprecipitation and analysed for their protein content by tandem mass spectrometry to identify host proteins with affinity for the movement tubule. Seven host proteins were abundantly present in the PM-tubule complex, including molecular chaperonins and an AAA protein. Members of both protein families have been implicated in establishment of systemic infection. The potential role of these proteins in tubule-guided cell-cell transport is discussed.