Plays a role in viral cell-to-cell propagation, by facilitating genome transport to neighboring plant cells through plasmosdesmata. May induce the formation of granular vesicles derived from the Endoplasmic reticulum, which align on actin filaments (By similarity). TGBp1, TGBp2 and TGBp3 seem to act together for cell-to-cell propagation. TGBp1 is the main movement protein that physically cross the plasmodesma with the viral genome. TGBp2 and TGBp3 would facilitate TGBp1 function. Belongs to the Tymovirales TGBp3 protein family.