Impaired and less polarized recruitment of phospho-FAK-Tyr925 to membrane ruffles in Eμ-TCL1^Tg;Rhoh^−/−CLL cells after chemokine stimulation. (A) Total FAK and (B) phospho-FAK expression determined by immunoblot in WT versus Rhoh^−/−CLL samples (WT versus Rhoh^−/−CLL; mean ± SEM, n = 3). (C) Primary murine CLL cells were stained for pFAK-Tyr925 (green), F-actin (rhodamine-phalloidin, red), and nuclear DAPI (blue). Merged confocal photomicrographs are also shown, all 600× magnification. On the right representative dot plots of pFAK-Tyr925 distribution pattern in CLL cells selected from 3 to 4 microscopic fields at 600× magnification. Arrowheads indicate accumulation of pFAK-Tyr925 in a polarized fashion in CXCL12 or CXCL13 stimulated WTCLL cells (representative of 2 independent experiments).