Development and precise characterization of phospho-site-specific antibody of Ser(357) of IRS-1: elimination of cross reactivity with adjacent Ser(358).

Antibodies that recognize specifically phosphorylated sites on proteins are widely utilized for studying the regulation and biological function of phosphoproteins. The proposed strategy is a powerful, analytical tool allowing the generation of phospho-site specific antibodies albeit adjacent phosphorylation sites are present. Here, we demonstrate the assessment and elimination of cross reactivity of phospho-site-specific-Ser(357) IRS-1 antibody.

Leptin down-regulates insulin action through phosphorylation of serine-318 in insulin receptor substrate 1.

Insulin resistance in skeletal muscle is found in obesity and type 2 diabetes. A mechanism for impaired insulin signaling in peripheral tissues is the inhibition of insulin action through serine phosphorylation of insulin receptor substrate (Irs) proteins that abolish the coupling of Irs proteins to the activated insulin receptor. Recently, we described serine-318 as a protein kinase C (PKC)-dependent phosphorylation site in Irs1 (Ser-318) activated by hyperinsulinemia.

The phosphorylation of Ser318 of insulin receptor substrate 1 is not per se inhibitory in skeletal muscle cells but is necessary to trigger the attenuation of the insulin-stimulated signal.

The Ser/Thr phosphorylation of insulin receptor substrate 1 (IRS) is one key mechanism to stimulate and/or attenuate insulin signal transduction. Using a phospho-specific polyclonal antibody directed against phosphorylated Ser(318) of IRS-1, we found a rapid and transient insulin-stimulated phosphorylation of Ser(318) in human and rodent skeletal muscle cell models and in muscle tissue of insulin-treated mice. None of the investigated insulin resistance-associated factors (e.

Shp2 is required for protein kinase C-dependent phosphorylation of serine 307 in insulin receptor substrate-1.

The function of insulin receptor substrate-1 (IRS-1), a key molecule of insulin signaling, is modulated by phosphorylation at multiple serine/threonine residues. Phorbol ester stimulation of cells induces phosphorylation of two inhibitory serine residues in IRS-1, i.e.

Insulin glulisine: insulin receptor signaling characteristics in vivo.

In recent years, recombinant DNA technology has been used to design insulin molecules that overcome the limitations of regular insulin in mealtime supplementation. However, safety issues have been raised with these alternatives, as the alteration of the three-dimensional structure may alter the interaction with the insulin and/or IGF-I receptors and therefore lead to the activation of alternate metabolic as well as mitogenic signaling pathways. It is therefore essential to carefully study acute and long-term effects in a preclinical state, as insulin therapy is meant to be a lifelong treatment.