APT1 and APT2 are overexpressed in primary CLL cells ex vivo. APT1 and APT2 mRNA expression was analyzed in healthy B cells (n = 4) and CLL cells (n = 7 [APT1] or n = 8 [APT2]) by quantitative PCR (A). Western blotting showed that APT1 and APT2 are overexpressed not only on mRNA, but also on protein level in CLL cells (n = 7 [APT1] or n = 9 [APT2]) compared with healthy B cells (n = 4 [APT1] or n = 5 [APT2]) (B-C). Global palmitoylation was analyzed by click chemistry. Comparison of CLL cells (n = 10), healthy PBMCs (n = 6), and healthy B cells (n = 6) revealed that the global palmitoylation level is significantly lower in CLL cells than in the healthy controls (D). Palmitoylation of proteins can be enhanced by the use of the depalmitoylation inhibitor PB (n = 5) (E). Means are given with their SEM. The statistical significance was determined using the Student t test. *P < .05, **P < .01, or ***P < .001 were considered significant.