FIG. 7.
Insulin regulates perilipin phosphorylation independently of Akt and correlates with glycerol release. (A) Following a glycerol release assay as shown in Fig. 2 and 3, lysates were immunoblotted for perilipin, tubulin, and the PKA phospho-substrate antibody; the dominant ∼60-kDa protein (identified as perilipin) is shown. Immunoblots were quantified using Licor Odyssey and normalized to tubulin. Data are expressed as means ± standard errors of the means from three experiments for Akt inhibitor experiments and means ± standard deviations from two experiments for W/M experiments. (B) Perilipin immunoprecipitates from 3T3-L1 adipocytes treated as shown (top) were blotted with phospho-PKA substrate or perilipin antibody as indicated. Additions were isoproterenol (Iso; 2 nM), insulin (Ins; 25 nM), Akt inhibitor (Akti; 10 μM), and wortmannin (W/M; 200 nM).