RAP1B and infection: Concurrently, subsequent experiments employing ap237 protein as a mimic of CaHEV capsid demonstrated that knockdown of Rap1b expression significantly impaired internalization of ap237 protein by LMH-1A2 cells, as demonstrated by confocal microscopy and Western blotting (Fig. 4C and D), which was consistent with CaHEV infection of LMH-1A2 cells after knockdown of Rap1b.