Fig. 5.

SIAH-2 binds and ubiquitylates α-synuclein. (A) Coimmunoprecipitation of SIAH-2 with α-synuclein from cotransfected HEK 293 cells. HA-α-synuclein was immunoprecipitated by using an anti-HA antibody. Coimmunoprecipitation of myc-SIAH-1 and myc-SIAH-2 was checked by using an anti-myc antibody. The asterisk depicts the faint SIAH-1 coimmunoprecipitation observed after prolonged exposure of the membrane. (B) Monoubiquitylation of α-synuclein was observed in the presence of GST-SIAH-2. Synphilin-1 was in vitro translated and incubated with the indicated components of the ubiquitin system, in the presence of 1 μg of GST-SIAH-2 or GST alone.