The study by Lei and Davis investigates the role of c-Jun NH2-terminal kinase (JNK) in the activation of Bax/Bak-dependent apoptosis. JNK is activated in response to environmental stress, including UV radiation, and is essential for UV-stimulated apoptosis. The researchers found that JNK phosphorylates two BH3-only proteins, Bim and Bmf, which are normally sequestered by binding to motor complexes. Phosphorylation by JNK disrupts the interaction between Bim/Bmf and their respective motor complexes, leading to their release and engagement of the mitochondrial apoptotic pathway. This mechanism provides a molecular link between the JNK signaling pathway and the Bax/Bak-dependent mitochondrial apoptotic machinery. The study also highlights the significance of Bim isoforms and their differential phosphorylation by MAPKs in regulating apoptotic responses.The study by Lei and Davis investigates the role of c-Jun NH2-terminal kinase (JNK) in the activation of Bax/Bak-dependent apoptosis. JNK is activated in response to environmental stress, including UV radiation, and is essential for UV-stimulated apoptosis. The researchers found that JNK phosphorylates two BH3-only proteins, Bim and Bmf, which are normally sequestered by binding to motor complexes. Phosphorylation by JNK disrupts the interaction between Bim/Bmf and their respective motor complexes, leading to their release and engagement of the mitochondrial apoptotic pathway. This mechanism provides a molecular link between the JNK signaling pathway and the Bax/Bak-dependent mitochondrial apoptotic machinery. The study also highlights the significance of Bim isoforms and their differential phosphorylation by MAPKs in regulating apoptotic responses.