Tanshinone IIA improves endoplasmic reticulum stress-induced insulin resistance through AMP-activated protein kinase

► ER stress suppressed insulin-mediated Akt phosphorylation and glucose uptake. ► Tanshinone IIA significantly reduced ER stress-impaired insulin action. ► Knockdown of AMPKα2 abolished Tanshinone IIA-mediated insulin sensitivity. ► Tanshinone IIA enhanced insulin sensitivity by increasing AMPK activity.