OBJECTIVE Polycystic ovary syndrome (PCOS) is a common endocrinologic disease in women. In the present study, we examined the relationship of the IRS-1 Gly972Arg and IRS-2 Gly1057Asp polymorphisms to PCOS and phenotypic features of PCOS in a Chinese population from Taiwan. MATERIALS AND METHODS A total of three hundred and forty genetically unrelated women with age from 18 to 45 years, includ...

Angiotensin II (ANG II) has been implicated in the pathogenesis of diabetic micro- and macrovascular disease. In vascular smooth muscle cells (VSMCs), ANG II phosphorylates and degrades insulin receptor substrate-1 (IRS-1). While the pathway responsible for IRS-1 degradation in this system is unknown, c-Jun NH(2)-terminal kinase (JNK) has been linked with serine phosphorylation of IRS-1 and ins...

Recently, we have reported that the overexpression of a membrane-targeted phosphatidylinositol (PI) 3-kinase (p110CAAX) stimulated p70S6 kinase, Akt, glucose transport, and Ras activation in the absence of insulin but inhibited insulin-stimulated glycogen synthase activation and MAP kinase phosphorylation in 3T3-L1 adipocytes. To investigate the mechanism of p110CAAX-induced cellular insulin re...

The period immediately after exercise is characterized by enhanced insulin action in skeletal muscle, and on the molecular level, by a marked increase in insulin-stimulated, phosphotyrosine-associated phosphatidylinositol (PI) 3-kinase activity. Because the increase in PI 3-kinase activity cannot be explained by increased insulin receptor substrate (IRS)-1 signaling, the present study examined ...

The insulin/insulin-like growth factor pathway is involved in breast and colorectal cancer (CRC) development. In the present study, we analyzed the coding region and short intron-exon borders of the insulin receptor substrate 1 and 2 (IRS‑1 and IRS‑2) genes in 12 cell lines derived from breast cancer (BC), 14 cell lines derived from CRC and 33 primary CRCs. The nucleotide variants identified in...

Insulin and insulin-like growth factor I (IGF-I) initiate cellular functions by activating their homologous tyrosine kinase receptors. In most mammalian cell types, this results in rapid tyrosine phosphorylation of a high-molecular-weight substrate termed insulin receptor substrate 1 (IRS-1). Previous studies suggest that IRS-1 may act as a "docking" protein that noncovalently associates with c...

Insulin receptor substrate-2 (IRS-2) belongs to the IRS family of adaptor proteins that function as signaling intermediates for growth factor, cytokine, and integrin receptors, many of which have been implicated in cancer. Although the IRS proteins share significant homology, distinct functions have been attributed to each family member in both normal and tumor cells. In cancer, IRS-2 is positi...

Serine and threonine phosphorylation has been shown to down-regulate insulin signaling at multiple steps, including the receptor and downstream molecules such as insulin receptor substrate-1 (IRS-1). To further address the mechanism of this regulation at the level of IRS-1, we constructed a double serine mutant of IRS-1: S662A/S731A-IRS-1. The serines 662 and 731 mutated to alanine are surround...

Incident Reporting Systems (IRS) are and will continue to be an important influence on improving patient safety. They can provide valuable insights into how and why patients can be harmed at the organizational level. However, they are not the panacea that many believe them to be. They have several limitations that should be considered. Most of these limitations stem from inherent biases of volu...

In neonatal animals, feeding stimulates skeletal muscle protein synthesis, a response that declines with development. Both the magnitude of the feeding response and its developmental decline can be reproduced by insulin infusion, suggesting that an altered responsiveness to insulin is a primary determinant of the developmental decline in the stimulation of protein synthesis by feeding. In this ...