Expression and microcluster formation of LAT mutants on a planar bilayer. (A) AND-Tg T cells expressing CD3ζ-Halo and mLAT(wt)-GFP, mLAT(C29A)-GFP, mLAT(C26,29A)-GFP, or LAXhLAT-GFP were loaded with TMR ligand and placed on the bilayer for 2 min. (B) AND-Tg T cells expressing CD3ζ-Halo and hLAT(wt)-GFP, hLAT(Y132F)-GFP, or hLAT(3YF)-GFP were placed on the bilayer for 2 min. (C) Numbers of clusters of GFP or Halo tag were counted objectively by software as described for Fig. 1. Data are means ± standard deviations of 15 to 30 cells. DIC, differential interference contrast.