ARF1 and infection: Interestingly, we observed a reduction in bacterial proliferation during WT STM infection after silencing ARF1. On the other hand, in the cells where constitutively active ARF1 (Q71L) was expressed (Dascher and Balch, 1994), the growth defect of the ΔsseI strain reverted similar to that of WT strain (Fig. 4G).