CXCL12-mediated CLL cell motility is dependent on a functional Rho/ROCK signal, whereas Rac is dispensable. (A) CLL cells were cultured on immobilized CXCL12 or collagen (COLL)/CXCL12, and activation of Rac1 (left) and RhoA (right) was analyzed (n = 4). (B) Rac1 activation in CCL19-treated CLL cells (n = 4). (C) Western blot analysis of phosphorylation of ezrin/radixin/moesin proteins and Vav1 from CLL cells cultured on immobilized CXCL12 or COLL/CXCL12. A representative blot out of 3 independent experiments is shown. (D) CLL cells were subjected to COLL with or without CXCL12, and cell motility was assessed using time-lapse videomicroscopy (n = 6) (left); a representative DIC image depicting the cell morphology also is shown (right). (E) CLL cells were pretreated with NSC-23766 before being subjected to COLL/CXCL12. CLL cell motility (n = 5) (left); a representative DIC image (right) also is shown. (F) CLL cells after pretreatment with Y-27632 before being cultured on COLL/CXCL12. CLL cell motility (n = 5) (left) and a representative DIC image (right). All data represent means ± SD. Scale bars represent 5 µm.