Figure 1. Leptin Induces Serine491 Phosphorylation of α2AMPK in Hypothalamus to Regulate Food Intake and Body Weight.
(A) α2AMPK αctivity, αAMPK serine485/491/α2AMPK, and AMPK threonine172 after saline or leptin injection (20 ng i.c.v.; 3 hr) in overnight fasted mice (n = 5–8/group). *p < 0.05 versus saline.
(B and C) GT1-7 neurons were transfected with Flag-WT or Flag-S491A-α2AMPK and treated with 0.5 μg/ml leptin (+) or vehicle (−) for 2 hr. Cell extracts were immunoprecipitated with α2AMPK antibody for (B and C, top panel) pSerine485/491/α2AMPK and pThreonine172 or (C, middle panel) α2AMPK activity or (B and C, lower panel) analyzed for pACCαβ/ACCαβ and actin. *p < 0.05 versus all other groups.
(D) Flag-WT and Flag-S491A α2AMPK expression in hypothalamic nuclei 8 days after adenovirus injection.
(E) Immunohistochemistry with Flag antibody. Low (left) and high (middle) magnification of ARC and VMH/DMH (top), PVN (middle row), and LH (bottom) after injection with Flag-S491A-α2AMPK adenovirus (columns 1 and 2) or null adenovirus (Empty) (top right, high magnification) are shown.
(F) Hypothalamic extracts were subjected to immunoprecipitation with α2AMPK antibody. Endogenous (Endo) and exogenous (Exo) (Flag-WT or Flag-S491A) α2AMPK phosphorylation was detected by immunoblotting.
(G and H) Changes in body weight and daily food intake after mediobasal hypothalamic injection of Flag-WT or Flag-S491A α2AMPK adenovirus (n = 22–24/group). *p < 0.05 versus mice expressing Flag-WT-α2AMPK.
Data in all panels are shown as means ± SEM. See also Figure S1.