Gp.Mur exhibited similar functionality as GPA in promoting AE1 expression. (A) Both GPA and Gp.Mur promoted AE1 biosynthesis. AE1 was subcloned in pCIG, a bicistronic construct containing the reporter gene green fluorescent protein. pCIG-AE1 was expressed alone, or together with GPA or Gp.Mur, in HEK293 cells. The transiently transfected cells were fixed, permeabilized, and stained with anti-AE1, BRIC71. The degrees of BRIC71 staining in the fixed and permeabilized cells reflected the relative expression levels of AE1 on intracellular and plasma membranes. (B) Both GPA and Gp.Mur promoted similar degrees of AE1 surface expression. Intact HEK293 cells were directly stained with BRIC71 after scraped off from culture plates. (Top) A representative BRIC71 histogram from flow cytometry. (Bottom) The intensities of BRIC71 staining for different coexpression groups were compared with that for the singly expressed AE1 (set at 1). Data were averaged from 8 to 9 independent experiments (as indicated next to each bar), and expressed as mean ± SE. P > .05 was deemed not significant (n.s.).