Figure 7.

Knockdown of MME may increase the rate of internalization of the insulin receptor. Immortalized human neck white subcutaneous preadipocytes were transiently transduced with either siRNA targeting MME (MMEKD) or non-targeting siRNA (Control) for 48 h before insulin signaling and receptor internalization experiments. Cells were starved for 24 h before a 0, 30-min, or 120-minute insulin stimulation followed by surface-receptor labeling (biotinylation), protein isolation, and Western blot. (A) Western blot of MME, pIR, biotin-IRβ, and actin in the MME knockdown. (B–C) Densitometric analysis of protein levels. Proteins were grouped by treatment (Control = black, MMEKD = red) and time (0, 30, or 120 min after 100 μM insulin stimulation). Asterisks indicate p ≤ 0.05 by 2-way ANOVA followed by a Tukey's test. N = 3. Bars indicate mean ± s.e.m.