Transports viral genome to neighboring plant cells directly through plasmosdesmata, without any budding. The movement protein allows efficient cell to cell propagation, by bypassing the host cell wall barrier. Increases plasmodesma size exclusion limit. Acts as a suppressor of RNA-mediated gene silencing, also known as post-transcriptional gene silencing (PTGS), a mechanism of plant viral defense that limits the accumulation of viral RNAs (By similarity). Homodimer and homooligomer. Interacts with capsid protein. Interacts with host AGO1; this interaction targets the host protein for degradation, thereby suppressing the antiviral RNA silencing (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 TGBp1 protein family.