Figure 1. PICK1 exists in multiple oligomeric states and oligomerization is reduced in the self-binding mutant PICK1^LKV.

(A) Representative SDS-PAGE (n=5) showing PICK1^WT (left) and PICK1^LKV (right). PICK1^WT elutes at 46 kD (monomer). A weak putative degradation product is also seen. PICK1^LKV displays only a band at 46 kD. (B) Size exclusion chromatography (SEC) of PICK1^WT (solid line), ultracentrifuged PICK1^WT (dashed line) and PICK1^LKV (dotted line). PICK1^WT (solid line) shows two major peaks. Peak 1 is removed by ultracentrifugation and is almost absent in PICK1^LKV. (C) Analytical ultracentrifugation (AUC) of fractions corresponding to peak 2 in the SEC. PICK1^WT (solid line) displays distinct peaks. PICK1^LKV displays reduced size of peaks corresponding to larger sizes. (D) Representative western blot showing lysates from COS7 cells transiently expressing PICK1^WT with or without pretreatment with the membrane permeable crosslinking agent DSS (n=3) (E) Representative confocal micrographs showing YFP-PICK1^WT (left) and YFP-PICK1^LKV (right) transiently expressed in COS7 cells (n=3). Arrows indicate clusters. Scale bar 10 μM. (F) Quantification of liposome vesiculation capacity of endophilin, PICK1^WT and PICK1^LKV in arbitrary units. Fluorescently labeled liposomes were incubated with indicated proteins before ultracentrifugation. Fluorescent lipids in the supernatant indicate scission from liposomes, which are pelleted (means ± sem, n=3, *p < 0.05). See also Figure S1.