Oligomerization of PPT1. (A) Cells were transfected with wild type pCMV5-PPT1 plasmids or/and with plasmids producing a GFP-fusion protein as indicated (GFP-PPT1, GFP-CLN3 or GFP-AIRE). The lysates were immunoprecipitated with anti-GFP-conjugated agarose beads. Both lysates (Transfection control) and immunoprecipitated samples (Anti-GFP-IP) were analyzed by immunoblotting using the anti-PPT1 antibody. * = Unspecific binding. (B) Biacore assay investigating the self-interaction of purified PPT1 (see methods).