Change in the mobility of HSCs/HPCs on VCAM-1 by Lnk deficiency or by Lnk inhibition with dPH/R364E/dC. (A) Increased trapping of Lnk-deficient Lin^-c-Kit⁺Sca-1⁺ cells by BM nucleated cells or by VCAM-1 in transmigration assay. Lin^- cells were purified from the Ly5.2⁺ wild-type (□) or Ly5.2⁺Lnk^-/- mice (▪), and their migration induced by CXCL12 was examined through noncoat membrane (membrane: noncoat; input cells: Lin^-), through noncoat membrane in the presence of Ly5.1⁺ total BM nucleated cells (noncoat, Lin^- plus total BM), or through VCAM-1–coated membrane (VCAM-1, Lin^-). Anti-α4 chain of the VLA-4 (anti-α4 Ab) or control antibody (control Ab) was added at the concentration of 10 μg/mL. Ly5.2⁺ Lin^-c-Kit⁺Sca-1⁺ cells in the bottom wells were counted, and the migration was determined as a percentage of total Ly5.2⁺ Lin^-c-Kit⁺Sca-1⁺ cells input into upper wells. Migration induced by CXCL12 through noncoat membrane was comparable between Lnk^+/+ (21% ± 7.6%) and Lnk^-/- cells (23% ± 3.4%). Results are represented as relative migration compared with that induced by CXCL12 through noncoat membrane, and mean values ± SD of data obtained from 3 experiments are shown. (B) Trapping of the wild-type Lin^-c-Kit⁺Sca-1⁺ cells by VCAM-1 was augmented by dPH/R364E/dC expression. Lin^- cells expressing eGFP alone (vector) or coexpressing dPH/R364E/dC with eGFP (dPH/R364E/dC) were subjected to transwell migration assay through noncoated membrane (noncoat: top panels) or through VCAM-1–coated membrane (VCAM-1: bottom panels). CXCL12-induced migration of Lin^-c-Kit⁺Sca-1⁺ cells (within boxes in the insets) was analyzed, and the percentage of GFP-positive transfectants was compared. Representative results of 3 experiments are shown.