Neuronal survival

Neuronal survival is a tightly regulated process critical for nervous system development, maintenance, and response to injury, primarily governed by balanced activation of pro-survival signaling cascades like PI3K/Akt and MAPK/ERK pathways downstream of neurotrophins such as NGF and BDNF. In cortical and cerebellar granule neurons, kinases like Cdk5/p35 play a key role by phosphorylating MEK1 to prevent sustained ERK1/2 activity, which otherwise triggers apoptosis through caspase-3 activation, TUNEL-positive cell death, and cytoskeletal disruptions including tau and neurofilament mislocalization from axons to cell bodies. Dysregulation, such as Cdk5 inhibition by roscovitine, leads to prolonged ERK signaling and neuronal death, rescuable by MEK inhibitors like PD98095, highlighting the need for precise temporal control. Neurons exhibit remarkable resilience, reversibly executing early apoptotic steps (e.g., c-Jun phosphorylation, BAX mitochondrial translocation, cytochrome c release) for up to 24-48 hours before irreversible degradation, dependent on BCL-xL for recovery. In disease contexts like neurodegeneration, failed survival signaling contributes to excessive apoptosis, while developmental roles ensure proper migration and lamination; no single molecule defines this process, but targeting modulators like Cdk5 holds therapeutic potential despite risks of pathway imbalance.

Other names

neuron viabilityanti-apoptotic signaling

Cdk5 phosphorylates MEK1 to downregulate transient ERK1/2 for survival; inhibition sustains ERK leading to apoptosis. BDNF/NGF activate ERK1/2-Rsk-CREB or ERK5-MEF2 for transcription-dependent survival. PI3K/Akt phosphorylates Bad to inhibit apoptosis.