Proinflammatory factor tumor necrosis factor-α (TNF-α) can inhibit serine phosphorylation of insulin receptor substrate-1 (IRS-1) by reducing the level of guanylate kinase related protein 42, thereby inhibiting the downstream glycogen synthesis and glucose transporter 4 (GLUT-4) activity to cause insulin resistance (78). Here, TNF is linked to Insulin resistance.