Rabbit Anti-Human IRS1 (Phospho-Ser612) polyclonal antibody

Lysosomal degradation of the endoplasmic reticulum (ER) via autophagy (ER-phagy) is emerging as a critical regulator of cell homeostasis and function. The recent identification ofER-phagy receptors has shed light on the molecular mechanisms underlining this process. However, the signaling pathways regulatingER-phagy in response to cellular needs are still largely unknown. We found that the nutrient responsive transcription factorsTFEBandTFE3-master regulators of lysosomal biogenesis and autophagy-controlER-phagy by inducing the expression of theER-phagy receptorFAM134B. TheTFEB/TFE3-FAM134B axis promotesER-phagy activation upon prolonged starvation. In addition, this pathway is activated in chondrocytes byFGFsignaling, a critical regulator of skeletal growth.FGFsignaling inducesJNK-dependent proteasomal degradation of the insulin receptor substrate 1 (IRS1), which in turn inhibits thePI3K-PKB/Akt-mTORC1 pathway and promotesTFEB/TFE3 nuclear translocation and enhancesFAM134B transcription. Notably,FAM134B is required for protein secretion in chondrocytes, and cartilage growth and bone mineralization in medaka fish. This study identifies a new signaling pathway that allowsER-phagy to respond to both metabolic and developmental cues.

Insulin resistance (IR) and inflammatory mediators are correlated with hepatic fibrosis. Quercetin is a bioflavonoid with well-known antidiabetic and antifibrotic properties. Bile duct ligation (BDL) is a surgical model performed on animals to produce a murine model in which increased oxidative stress occurs, which results in liver fibrosis. Our study aimed to determine whether quercetin improves hepatic IR as well as hepatic fibrosis in rats experiencing BDL. Male Wistar rats were allocated to four groups according to a random pattern, including a sham group, a sham and quercetin group (30 mg/kg/day), a BDL alone group, and a BDL and quercetin group (30 mg/kg/day). Evaluation of STAT3, SOCS3, IRS1, Rac1, Rac1-GTP, Sp1, NOX1, HIF-1 alpha, and ERK1 expression was performed by RT-PCR along with the western blot analytical technique in liver tissue. The antidiabetic impact of quercetin was associated with reduction in mRNA and expression of protein in STAT3 and SOCS3, along with an increase in IRS1. The antifibrotic effect of quercetin was also determined by downregulation of mRNA or the levels of protein expression of Rac1-GTP, Rac1, HIF-1 alpha, NOX1, and Sp1, along with ERK1. Our study indicates that quercetin may improve hepatic fibrosis via inhibiting ROS-associated inflammation as well as ameliorating hepatic IR by beneficial regulation of the STAT3/SOCS3/IRS1 signaling pathway.