The possible roles of septins in synaptic plasticity and mechanisms of neurodegeneration. SEPT4, SEPT5 and SEPT8 have been hypothesized to control synaptic vesicle trafficking at the presynaptic terminal by interacting with different components of the SNARE complex and regulating synaptic vesicle localization at the presynaptic membrane. Also SEPT2 and SEPT4 may regulate neurotransmitter levels at the synapse by regulating glutamate transporter localization in astrocytes. Additionally, SEPT4 may affect caspase-3 activity. SEPT4 functions are possibly regulated by DYRK1A-mediated phosphorylation. Septins also are known to interact with actin and microtubules, suggesting that they may affect tau. SEPT1, 2, and 4 have been found to localize in in NFTs.