Clampit Jill E, Meuth Joseph L, Smith Harriet T, Reilly Regina M, Jirousek Michael R, Trevillyan James M, Rondinone Cristina M
Insulin Signaling, Metabolic Diseases Research, Global Pharmaceutical Research Division, Abbott Laboratories, Department 47R, Building AP10, 100 Abbott Park Road, Abbott Park, IL 60064-6009, USA.
Biochem Biophys Res Commun. 2003 Jan 10;300(2):261-7. doi: 10.1016/s0006-291x(02)02839-5.
Protein-tyrosine phosphatase-1B (PTP1B) has been implicated as a negative regulator of insulin signaling. PTP1B dephosphorylates the insulin receptor and insulin receptor substrates (IRS-1/2), inhibiting the insulin-signaling pathway. PTP1B has been reported to be elevated in diabetes and insulin-resistant states. Conversely, PTP1B null mice have increased insulin sensitivity. To further investigate the effect of PTP1B reduction on insulin signaling, FAO rat hepatoma cells were transfected, by electroporation, with a specific PTP1B antisense oligonucleotide (ASO), or a control oligonucleotide. The PTP1B ASO caused a 50-70% reduction in PTP1B protein expression as measured by Western blot analysis. Upon insulin stimulation, an increase in the phosphorylation of the insulin receptor and insulin receptor substrates was observed, without any change in protein expression levels. Reduction of PTP1B expression in FAO cells also caused an increase in insulin-stimulated phosphorylation of PKB and GSK3, without any change in protein expression. These results demonstrate that reduction of PTP1B can modulate key insulin signaling events downstream of the insulin receptor.
蛋白酪氨酸磷酸酶-1B（PTP1B）被认为是胰岛素信号传导的负调节因子。PTP1B使胰岛素受体和胰岛素受体底物（IRS-1/2）去磷酸化，从而抑制胰岛素信号通路。据报道，在糖尿病和胰岛素抵抗状态下，PTP1B水平会升高。相反，PTP1B基因敲除小鼠的胰岛素敏感性增加。为了进一步研究降低PTP1B对胰岛素信号传导的影响，通过电穿孔法将特定的PTP1B反义寡核苷酸（ASO）或对照寡核苷酸转染到FAO大鼠肝癌细胞中。通过蛋白质印迹分析测量，PTP1B ASO使PTP1B蛋白表达降低了50%-70%。在胰岛素刺激后，观察到胰岛素受体和胰岛素受体底物的磷酸化增加，而蛋白表达水平没有任何变化。FAO细胞中PTP1B表达的降低还导致胰岛素刺激的蛋白激酶B（PKB）和糖原合成酶激酶3（GSK3）磷酸化增加，蛋白表达没有任何变化。这些结果表明，降低PTP1B可以调节胰岛素受体下游的关键胰岛素信号事件。
