Diagram depicting possible explanations for some of the virus–host interactions with host proteins during movement. Many viruses replicate in replication centers (RC) rich in ER. The viral RNA extending from the replicase is bound by proteins involved in movement, and the MC is assembled with viral and host factors (a). The MC may then move with the rapid flow of the ER membranes (indicated by the chevrons; b). The viral proteins may bind to peripheral markers such as attachment points or PD-targeted proteins such as calreticulin (CRT) when encountered (c). Through associations with cell wall enzymes such as PME, viral-movement-associated proteins may loosen the wall structure (d), and Hsp70-like proteins may translocate the MP-RNA complex through the pore (e). Later in infection, movement-associated proteins are probably targeted for degradation. For TMV, calreticulin may play a role in removing the MP from the ER for degradation by the proteasome (P), with the excess binding to the microtubules (f). N and CW indicate the nucleus and cell wall, respectively.