Fig 3.
Mutational analysis identifies amino acids important for ITM-mediated B7-2 downregulation. (A) Analysis of the MIR2 ITM region by alanine substitution mutagenesis. FLAG-tagged B7-2JM-CYT was cotransfected with control GFP (mock) or the indicated GFP mutant MIR2 vector, and the cell surface expression level of B7-2JM-CYT was analyzed by flow cytometry. The relative activity of each mutant MIR2 is shown. Error bars represent SD (n = 3). Double asterisks indicate significant difference (P < 0.01). (B) Analysis of the B7-2 JM region by alanine substitution mutagenesis. FLAG-tagged B7-2JM-CYT or the indicated mutant FLAG-tagged B7-2JM-CYT was cotransfected with the control GFP or GFP-MIR2 vector, and the cell surface expression level of each mutant was analyzed by flow cytometry. The relative sensitivity of each mutant B7-2JM-CYT is shown. Error bars represent SD (n = 3). The asterisk indicates significant difference (P < 0.05).