File:Eps8-Regulates-Axonal-Filopodia-in-Hippocampal-Neurons-in-Response-to-Brain-Derived-Neurotrophic-pbio.1000138.s006.ogv

English: The dynamic formation of axonal filopodia is significantly increased in eps8−/− as compared to WT hippocampal neurons. Hippocampal neurons (3DIV) were obtained from E18 WT (top) and eps8 null (bottom) mice. The dissociated cells were plated onto glass coverslips coated with poly-l-lysine at densities ranging from 10,000 to 20,000 cells/cm2. After a few hours, the coverslips were transferred to dishes containing a monolayer of cortical glial cells. Live imaging recording was performed by Zeiss LSM 510 Meta. Frames were taken every 5 s for a total of 4 min. Bar indicates 10 µm. Insets show a magnified detail of filopodia dynamically emerging and retracting from the axonal shaft. It is evident from these movies that the average length of filopodia (3.6±0.8 standard error of the mean [SEM], n = 50) is not significantly affected by removal of Eps8, which instead causes an increase in the number of cell-forming filopodia and in the density of filopodia along the axon. This suggests that the capping activity of Eps8 likely regulates initiation rather than elongation of filopodia. Additionally, expression of high levels of ectopic eps8 blocks the formation of filopodia rather than preventing their elongation (Figure 3).