【文章名】Heart 6-phosphofructo-2-kinase activation by insulin requires PKB (protein kinase B), but not SGK3 (serum- and glucocorticoid-induced protein kinase 3)
Heart 6-phosphofructo-2-kinase activation by insulin requires PKB (protein kinase B), but not SGK3 (serum- and glucocorticoid-induced protein kinase 3)
[摘要]：On the basis of transfection experiments using a dominant-negative approach. our previous studies suggested that PKB (protein kinase B) was not involved in heart PFK-2 (6-phosphofructo2-kinase) activation by insulin. Therefore we first tested whether SGK3 (serum- and glucocorticoid-induced protein kinase 3) might be involved in this effect. Treatment of recombinant heart PFK-2 with [gamma-P-32]ATP and SGK3 in vitro led to PFK-2 activation and phosphorylation at Ser(466) and Ser(483). However, in HEK-293T cells [HEK (human embryonic kidney)-293 cells expressing the large T-antigen of SV40 (simian virus 40)] co-transfected with SGK3 siRNA (small interfering RNA) and heart PFK-2, insulin-induced heart PFK-2 activation was unaffected. The involvement of PKB in heart PFK-2 activation by insulin was re-evaluated using different models. (i) hearts from transgenic mice with a muscle/heart-specific mutation in the PDK1 (phosphoinositide-dependent protein kinase 1)-substrate-docking site injected with insulin hearts from PKB beta-deficient mice injected with insulin; (m) freshly isolated rat cardiomyocytes and perfused hearts treated with the selective Akt1-1/2 PKE. inhibitor prior to insulin treatment; and (iv) HEK-293T cells co-transfected with heart PFK-2, and PKB alpha/beta siRNA or PKB alpha siRNA, incubated with insulin Together, the results indicated that SGK3 is not required for insulin-induced PFK-2 activation and that this effect is likely mediated by PKB alpha
