In brain development, apoptosis is a physiological process that controls the final numbers of neurons. Here, we report that the activity-dependent prevention of apoptosis in juvenile neurons is regulated by kinesin superfamily protein 4 (KIF4), a microtubule-based molecular motor. The C-terminal domain of KIF4 is a module that suppresses the activity of poly (ADP-ribose) polymerase-1 (PARP-1), a nuclear enzyme known to maintain cell homeostasis by repairing DNA and serving as a transcriptional regulator. When neurons are stimulated by membrane depolarization, calcium signaling mediated by CaMKII induces dissociation of KIF4 from PARP-1, resulting in upregulation of PARP-1 activity, which supports neuron survival. After dissociation from PARP-1, KIF4 enters into the cytoplasm from the nucleus and moves to the distal part of neurites in a microtubule-dependent manner. We suggested that KIF4 controls the activity-dependent survival of postmitotic neurons by regulating PARP-1 activity in brain development.
