GAP43 is a protein involved in neurodevelopment, neuroplasticity and neurorecovery of the central nervous system. It plays a significant role in synaptogenesis and is, therefore, responsible for learning and memory. The gene for GAP43 is located on the third chromosome, and the protein is synthesized in the body of the neuron, from where it is transported by vesicles to its functional location on growth cones and presynaptic terminals. The GAP43 protein is attached to the membrane by palmitic acid. Phosphorylated GAP43 fulfils its role in axon growth and growth cone guidance by influencing the dynamics of actin filaments and, thus, the patterning of the membrane that forms synaptic connections. GAP43 also exerts its role by modulating the availability of phosphatidylinositol 4,5-bisphosphate (PIP2) at the plasma membrane and provides the signalling pathways crucial for cellular functioning. The expression level of GAP43 is affected by various pathological conditions. GAP43 expression is increased after traumatic brain injury, suggesting a possible role in neurorecovery. GAP43 is also involved in various neurodegenerative conditions, such as Alzheimer's disease and Parkinson's disease. In Alzheimer's disease, dysregulation and accumulation of non-functional GAP43 may contribute to the underlying pathophysiological processes. On the other hand, a reduced level of functional GAP43 may worsen the patient's health condition. Decreased concentration of functional GAP43 also contributes to the pathogenesis of Parkinson's disease due to the enhanced creation of glial scars and increased pathological destruction of cells that are part of the nigrostriatal pathway.