KIR2DL1 and GFP membrane expression on Jurkat transfectants and KIR2DL1 mutants. (A) The protein-coding region of KIR2DL1 or mutated KIR2DL1 was inserted into pEGFP-N1, and Jurkat T cells were stably transfected with the recombinant DNA and pEGFP-N1 empty vector. Three of the geneticin-resistant transfectants expressing KIR2DL1 at the membrane (JK9.12, JK32, JK61) and mutated KIR2DL1 (2ΔY/D8, 2ΔY/F11, 2ΔY/H12) were selected. GFP and KIR2DL1 (shaded histograms) or isotypic control (open histograms) levels were determined by flow cytometry. Numbers in parentheses are mean fluorescence intensities (MFI). (B) KIR2DL1-ITIMs sequences of wild-type KIR2DL1 and with amino acid substitutions in double Tyr mutant (2ΔY) are shown. (C) Confocal microscopic analysis of KIR2DL1/GFP distribution in Jurkat KIR2DL1-GFP transfectants.