PANDER binds to the liver cell membrane and inhibits insulin signaling in HepG2 cells

PANDER is a cytokine co-secreted with insulin from islet β-cells. To date, the physiological function of PANDER remains largely unknown. Here we show that PANDER binds to the liver membrane by 125I-PANDER saturation and competitive binding assays. In HepG2 cells, pre-treatment with PANDER ranging from 4 pM to 4 nM for 8 h resulted in a maximal inhibition of insulin-stimulated activation of insulin receptor and insulin receptor substrate 1 by 52% and 63%, respectively. Moreover, PANDER treatment also reduced insulin-stimulated PI3K and pAkt levels by 55% and 48%, respectively. In summary, we have identified the liver as a novel target for PANDER, and PANDER may be involved in the progression of diabetes by regulating hepatic insulin signaling pathways.