Figure 5.
Parkin mediates K63-linked polyubiquitination of synphilin-1. A, A portion of lysates prepared from HEK 293 cells transfected with FLAG-tagged parkin alone or with various HA-tagged ubiquitin species were subjected to anti-FLAG immunoprecipitation followed by anti-HA immunoblotting (left panel). The blot was stripped and reprobed with anti-FLAG to show the amounts of immunoprecipitated parkin (top right panel). Lysates prepared from these variously transfected cells (INPUT) were also subjected to anti-FLAG immunoblotting to show FLAG-parkin expression levels (bottom right panel). B, A portion of lysates prepared from HEK 293 cells transfected with the indicated combinations of myc-tagged synphilin-1, FLAG-tagged parkin, and various HA-tagged ubiquitin species were subjected to anti-myc immunoprecipitation followed by anti-HA immunoblotting (top left panel). The blot was stripped and reprobed with anti-myc (bottom left panel) to illustrate that relatively equal amounts of synphilin were immunoprecipitated. The remaining portion of the transfected cell lysates was immunoblotted with anti-HA (top right panel) and anti-myc (bottom right panel) to show their respective expression levels. These experiments were replicated at least three times.