Figure 4.

α-Synuclein aggregation in differentiated human neuroblastoma cells. A, Schematic presentation of differentiation and α-synuclein expression. α-Synuclein is expressed for 3 d in cells at different stages of differentiation. B, Western analysis of α-synuclein aggregation. The first lane (0^*) of each panel shows the naive SH-SY5Y cells infected and processed in the same way. Note that the level of α-synuclein aggregation increases with a longer period of differentiation in both Triton-soluble (TX-s) and Triton-insoluble (TX-p) fractions. C, Sedimentation analysis of α-syn aggregates. Detergent extract of differentiated SH-SY5Y cells overexpressing α-syn was subjected to a sequential differential centrifugation. Cells were treated with 20 nm Baf before the extraction to enrich the aggregates (see Fig. 5). Numbers at the top indicate the centrifugal forces in gravity (g). S and P indicate the supernatant and the pellet of each centrifugation, respectively.