Figure 4.

Ataxin3 VBM is necessary and sufficient for interaction with p97. A, alignment of the VBMs from different ataxin3 homologs showing conservation across species. B, SDS-polyacrylamide gel of the different purified ataxin3 constructs used, stained with Coomassie Brilliant Blue. C, schematic representation of the ataxin3 constructs shown in B. D, left, representative SPR responses for ataxin3 constructs binding to immobilized full-length p97 (for all constructs, analyte concentration = 10 μm); right, normalized equilibrium binding responses for the same constructs, fit to a one-site binding model (n ≥ 3 for each concentration). The dashed line in the left panel represents the response range used to determine the equilibrium fit. E, and F, ITC raw and fitted data for the binding of the p97 N-domain to ataxin3 deletion constructs. E, injection of ataxin3ΔC into the p97 N-domain; F, injection of ataxin3ΔN into the p97 N-domain.