Effects of arsenic on c-CBL and BCR-ABL in CML cells. (A) Without arsenic treatment, c-CBL is self-ubiquitinated and degraded in proteasome. (B) Arsenic treatment inhibits c-CBL self-ubiquitination and proteasomal degradation, and triggers ubiquitination of BCR-ABL at K1517 followed by degradation in the proteasome.