active akt2 enzyme  (Sino Biological)

Journal: Diabetes

Article Title: Akt-Dependent Phosphorylation of Hepatic FoxO1 Is Compartmentalized on a WD40/ProF Scaffold and Is Selectively Inhibited by aPKC in Early Phases of Diet-Induced Obesity

doi: 10.2337/db13-1863

Figure Lengend Snippet: Development of hepatic and secondary systemic insulin resistance in DIO. In response to dietary excess, availability of lipids that directly activate aPKC, e.g., ceramide and phosphatidic acid, increases. Subsequent activation of hepatic aPKC increases binding of aPKC to ProF, a scaffolding protein that couples Akt and FoxO1, and this leads to impaired ability of Akt2 to phosphorylate FoxO1 on Ser 256 ; as a result, expression of PEPCK and G6Pase and hepatic glucose output increase. Ensuing increases in blood glucose levels stimulate insulin secretion, and both glucose and insulin, as well as fatty acids, increase phosphatidic acid production via the de novo pathway. Increased insulin secretion activates hepatic Akt2, as well as aPKC, which together increase hepatic lipid production, thereby providing more substrates for phosphatidic acid and ceramide synthesis. In short, a vicious cycle is set up for lipid production and aPKC activation. This cycle is abetted in human (but not rodent) liver by virtue of the fact that increased aPKC activity provokes increases in levels of PKC-ι mRNA and protein . As a by-product of increases in circulating levels of liver-derived lipids and cytokines, insulin signaling in muscle and certain other tissues (e.g., adipose tissue [data not shown]) is impaired, adding further to diminished glucose disposal and systemic insulin resistance.

Article Snippet: Akt2 enzyme activity was assayed in immunoprecipitates using a kit purchased from Millipore as previously described ( – , ).

Techniques: Activation Assay, Binding Assay, Scaffolding, Expressing, Activity Assay, Derivative Assay