The ADAP/SKAP55 module controls T-cell migration in vitro and in vivo. (A) Purified splenic WT and ADAP^−/− T cells were placed into the upper part of transwell chambers. Cells were incubated in the absence or presence of CCL21 in the upper and/or lower chamber for 2 hours. Migrated T cells (lower chamber) were counted and calculated as percentage of input cell numbers (mean ± SD; n = 8 mice each). **P ≤ .001. (B) A mixture of equal numbers of CFSE-labeled WT and DDAO-SE–labeled ADAP^−/− purified T cells was adoptively transferred into 4 genetically matched WT recipients. After 2 or 18 hours, the percentage of labeled lymphocytes from pLN (mesenteric [MLN], auxiliary [ALN], and inguinal [ILN]), as well as the spleen was determined by flow cytometry, and the homing index was calculated as the ratio of ADAP^−/− to WT T-cell numbers. The graph summarizes the data of 2 independent experiments (mean ± SD; n = 8 recipient mice).