STX18 and infection: On the other hand, a robust signal of mRFP-Sec22b recruited to the LCV during the remodeling stage was still detectable on the LCV in Stx18-silenced cells at 6 h post infection even though its signal disappeared around the LCV in mock-treated cells, likely due to diffusion of mRFP-Sec22b into the ER after ER-LCV fusion (Fig 5B).