FIGURE 3.

Circulating progranulin is found in complexes of ∼180–190 kDa, partially co-elutes with HDL by gel-filtration, and is not associated with lipids. A, progranulin in mouse and human plasma is in a complex of ∼180–190 kDa and partially co-elutes with HDL. Dot blots of gel-filtration fractions 1–47 and plasma (blue box) from wild-type mice (left panel), Grn^−/− mice (middle panel), and a human subject (right panel) are shown. The fractions corresponding to HDL are indicated by the red box. B, progranulin in mouse plasma partially co-elutes with HDL. Western blots of gel-filtration fractions 25–38 from wild-type mouse plasma are shown. These results are from a representative experiment that was performed four times with similar results. C, cholesterol profiles of plasma from wild-type (black line) and Grn^−/− (red line) mice are shown. IDL, intermediate density lipoproteins. D, circulating progranulin is not associated with lipids. Delipidation of mouse (left panel) and human (right panel) plasma results in a shift in the gel-filtration elution profile of apoA-I but not in that of progranulin. Western blots of gel-filtration fractions 1–48 for control and delipidated mouse plasma. Similar results were obtained in two independent experiments.