Figure 7. Post-translational modification of POSH is associated with differential scaffold composition between CD4⁺ and CD8⁺ T cells.

(A) Model representing the composition and arrangement of POSH complexes in CD4⁺ and CD8⁺ T cells. (B) Naïve polyclonal CD4⁺ and polyclonal CD8⁺ T cells were stimulated with α-CD3 and α-CD28 in the presence of IL-2 for 4 days and the levels of POSH, Tak1 and JIP-1 were assessed by flow cytometry. (C) Model depicts the organization of the functional domains in POSH and shows the location of modifiable tyrosines. (D) T cells were treated as in (B) and lysates were subjected to IP with POSH and the levels of p-tyrosine (p-Y) was determined by immunoblot. Graph shows the relative units (rU) of p-Y-POSH calculated as the ratio to POSH for each cell. All experiments are representative of n>3 independent experiments. ** indicates p < 0.01.