MARCH2+/+ HEK293T cells harboring empty vector or MARCH2-/- HEK293T cells harboring empty vector, Flag-tagged MARCH2, or MARCH2CCH (a mutant harboring mutations in residues within the catalytic domain: C64S, C67S, and H90Q) were infected with VSV-GFP (MOI = 0.05). by measuring GFP expression using a fluorescence modulator 