Expression of Unc119 partially restores Lck trafficking in the presence of Nef. Effects of coexpression of MAL and Unc119 on Nef-mediated RE/TGN targeting of Lck. (A) Representative confocal micrographs of Jurkat T lymphocytes cotransfected with expression plasmids for the indicated proteins. Myc and HA refers to empty control plasmids that encode only for the respective epitope tag. Shown is the distribution of Lck; red asterisks indicate cotransfected cells. Scale bar indicates 10 μm. Note that the expression of Unc119.HA releases Lck from the Nef-induced RE/TGN accumulation into a diffuse cytoplasmic distribution. (B) Frequencies of cells with RE/TGN accumulation of Lck. Values are the arithmetic means of at least 3 independent experiments ± SD in which more than 100 cells were counted per condition. (C) Effect of Unc119 coexpression on IS recruitment of Lck in the presence of Nef. Shown are representative micrographs of Jurkat T lymphocytes expressing GFP or Nef.GFP (green) in conjugates with SEE-pulsed Raji B cells (blue). Active p-Lck505&394 is depicted in red. Note that RE/TGN targeting and inhibition of IS recruitment of p-Lck505&394 by Nef is reversed by coexpression of Unc119.HA (dark blue). Scale bar indicates 10 μm. (D) Frequencies of RE/TGN accumulation versus IS recruitment of p-Lck505&394. Values are the arithmetic means of at least 3 independent experiments ± SD in which more than 100 cells were counted per condition.