Total HS1 phosphorylation is reduced following LYN inhibition in a subset of CLL patients. Total HS1 phosphorylation was evaluated by 2DE of CLL primary samples after 1 hour of culture in the presence or absence of 100 nM dasatinib. Representative samples of active-HS1 (A) and inactive-HS1 (B) are shown. The more phosphorylated protein spot (left spot) and the less phosphorylated protein spot (right) are separated by a black dashed line, and the percentage of OD of the total HS1 signal is displayed. The arrow indicates the direction of pI increase from more acidic (lower pI) to more basic (higher pI) positions in the 2D gel, showing, after dasatinib treatment, a shift of the left protein spot to a less acidic right position on gel (A) that is not evident in (B). In the dot plots [(C), active-HS1; (D), inactive-HS1], means ± SEM of the percentage of OD of the total HS1 signal (before and after treatment) as cumulative analyses of 3 patients per group are displayed. *P ≤ .05. ns, not significant, paired Student t test. pI, isoelectric point.