Effect of NYGGF4 on insulin signaling transduction. 3T3-L1 preadipocytes transfected with NYGGF4 or the empty vector were induced to differentiate. After incubation with or without 100 nmol/L insulin for 30 min, the cell lysates were analyzed by SDS-PAGE, blotted onto a membrane, and then probed with antibodies against molecules involved in the insulin signal pathway. The results are representative of those obtained from three independent experiments. A–F represent the total protein concentration and phosphorylation level of AKT, ERK, p38, JNK, IRS-1, and IR, respectively.