Insulin receptor-deficient β-cells show reduced expression of cyclins and cyclin dependent kinases and nuclear restriction of FoxO1.

<p>(a) Reduced expression of cdk2 and cdk4; (b) reduced expression of cyclin D2, cyclin D3 and cyclin E; (c) increased expression and nuclear restriction of FoxO1; (d) re-expression of the insulin receptor in βIRKO β-cells (βIRKO+hIRB) restores the expression of CDK2, CDK4 and cyclin E. Actin is used as a loading control; (e) reduced p-IRS2 and p-S473-Akt in βIRKO and restoration of total IRS2, pIRS2 and p-S473-Akt in insulin receptor re-expressing cells (βIRKO+hIRB); (f) Re-expression of insulin receptors in βIRKO cells restores FoxO1 to nucleus; (g) proliferation analyzed by the deuterated water technique <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028050#pone.0028050-Neese1" target="_blank">[57]</a>. Representative data from at least 3 independent Western blotting experiments from at least 2 independent clones are shown. The plots below the blots are shown in arbitrary units. The loading control for experiments in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028050#pone-0028050-g004" target="_blank">Fig. 4a–c</a> is presented under the blot for cyclin D3 in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0028050#pone-0028050-g004" target="_blank">Fig. 4b</a>. *, p<0.05 βIRKO vs Control or βIRKO+hIRB.