scholarly journals Modulation of human insulin receptor substrate-1 tyrosine phosphorylation by protein kinase Cdelta

2004 ◽  
Vol 378 (1) ◽  
pp. 105-116 ◽  
Author(s):  
Michael W. GREENE ◽  
Nick MORRICE ◽  
Robert S. GAROFALO ◽  
Richard A. ROTH
Keyword(s):  
Fatty Acid ◽  
Protein Kinase ◽  
Insulin Receptor ◽  
Tyrosine Phosphorylation ◽  
Inhibitory Effect ◽  
Insulin Receptor Substrate ◽  
Triple Mutant ◽  
Insulin Receptor Substrate 1

Non-esterified fatty acid (free fatty acid)-induced activation of the novel PKC (protein kinase C) isoenzymes PKCδ and PKCθ correlates with insulin resistance, including decreased insulin-stimulated IRS-1 (insulin receptor substrate-1) tyrosine phosphorylation and phosphoinositide 3-kinase activation, although the mechanism(s) for this resistance is not known. In the present study, we have explored the possibility of a novel PKC, PKCδ, to modulate directly the ability of the insulin receptor kinase to tyrosine-phosphorylate IRS-1. We have found that expression of either constitutively active PKCδ or wild-type PKCδ followed by phorbol ester activation both inhibit insulin-stimulated IRS-1 tyrosine phosphorylation in vivo. Activated PKCδ was also found to inhibit the IRS-1 tyrosine phosphorylation in vitro by purified insulin receptor using recombinant full-length human IRS-1 and a partial IRS-1–glutathione S-transferase-fusion protein as substrates. This inhibition in vitro was not observed with a non-IRS-1 substrate, indicating that it was not the result of a general decrease in the intrinsic kinase activity of the receptor. Consistent with the hypothesis that PKCδ acts directly on IRS-1, we show that IRS-1 can be phosphorylated by PKCδ on at least 18 sites. The importance of three of the PKCδ phosphorylation sites in IRS-1 was shown in vitro by a 75–80% decrease in the incorporation of phosphate into an IRS-1 triple mutant in which Ser-307, Ser-323 and Ser-574 were replaced by Ala. More importantly, the mutation of these three sites completely abrogated the inhibitory effect of PKCδ on IRS-1 tyrosine phosphorylation in vitro. These results indicate that PKCδ modulates the ability of the insulin receptor to tyrosine-phosphorylate IRS-1 by direct phosphorylation of the IRS-1 molecule.

scholarly journals Angiotensin II induces tyrosine phosphorylation of insulin receptor substrate 1 and its association with phosphatidylinositol 3-kinase in rat heart

1995 ◽  
Vol 310 (3) ◽  
pp. 741-744 ◽  
Author(s):  
M J A Saad ◽  
L A Velloso ◽  
C R O Carvalho
Keyword(s):  
Angiotensin Ii ◽  
Insulin Receptor ◽  
Tyrosine Phosphorylation ◽  
Rat Heart ◽  
Fold Increase ◽  
At1 Receptor ◽  
Insulin Receptor Substrate ◽  
Phosphatidylinositol 3 Kinase ◽  
Insulin Receptor Substrate 1

We have investigated whether angiotensin II (AII) is able to induce insulin receptor substrate 1 (IRS-1) phosphorylation and its association with phosphatidylinositol 3-kinase (PI 3-kinase) in the rat heart in vivo. The phosphorylation state of IRS-1 following infusion of insulin or AII via the vena cava was assessed after immunoprecipitation with an anti-peptide antibody to IRS-1 followed by immunoblotting with an anti-phosphotyrosine antibody and an anti-PI 3-kinase antibody. Densitometry indicated a 5.6 +/- 1.3-fold increase in IRS-1 phosphorylation after stimulation with AII and a 12.8 +/- 3.1-fold increase after insulin. The effect was maximal at an AII concentration of 10(-8) M and occurred 1 min after infusion. There was also a 6.1 +/- 1.2-fold increase in IRS-1-associated PI 3-kinase in response to AII. In the isolated perfused heart the result was similar, showing a direct effect of AII on this pathway. When the animals were pretreated for 1 h with DuP 753, a non-peptide AII-receptor 1 (AT1 receptor) antagonist, there was a marked reduction in the AII-induced tyrosine phosphorylation of IRS-1, suggesting that phosphorylation is initially mediated by the AT1 receptor. We conclude that AII stimulates tyrosine phosphorylation of IRS-1 and its association with PI 3-kinase. This pathway thus represents an additional signalling mechanism stimulated by AII in the rat heart in vivo.

scholarly journals The Adapter Protein ZIP Binds Grb14 and Regulates Its Inhibitory Action on Insulin Signaling by Recruiting Protein Kinase Cζ

2002 ◽  
Vol 22 (20) ◽  
pp. 6959-6970 ◽  
Author(s):  
Bertrand Cariou ◽  
Dominique Perdereau ◽  
Katia Cailliau ◽  
Edith Browaeys-Poly ◽  
Véronique Béréziat ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Insulin Receptor ◽  
Insulin Signaling ◽  
Inhibitory Action ◽  
Catalytic Domain ◽  
Inhibitory Effect ◽  
Negative Regulator ◽  
Interacting Protein

ABSTRACT Grb14 is a member of the Grb7 family of adapters and acts as a negative regulator of insulin-mediated signaling. Here we found that the protein kinase Cζ (PKCζ) interacting protein, ZIP, interacted with Grb14. Coimmunoprecipitation experiments demonstrated that ZIP bound to both Grb14 and PKCζ, thereby acting as a link in the assembly of a PKCζ-ZIP-Grb14 heterotrimeric complex. Mapping studies indicated that ZIP interacted through its ZZ zinc finger domain with the phosphorylated insulin receptor interacting region (PIR) of Grb14. PKCζ phosphorylated Grb14 under in vitro conditions and in CHO-IR cells as demonstrated by in vivo labeling experiments. Furthermore, Grb14 phosphorylation was increased under insulin stimulation, suggesting that the PKCζ-ZIP-Grb14 complex is involved in insulin signaling. The PIR of Grb14, which also interacts with the catalytic domain of the insulin receptor (IR) and inhibits its activity, was preferentially phosphorylated by PKCζ. Interestingly, the phosphorylation of Grb14 by PKCζ increased its inhibitory effect on IR tyrosine kinase activity in vitro. The role of ZIP and Grb14 in insulin signaling was further investigated in vivo in Xenopus laevis oocytes. In this model, ZIP potentiated the inhibitory action of Grb14 on insulin-induced oocyte maturation. Importantly, this effect required the recruitment of PKCζ and the phosphorylation of Grb14, providing in vivo evidences for a regulation of Grb14-inhibitory action by ZIP and PKCζ. Together, these results suggest that Grb14, ZIP, and PKCζ participate in a new feedback pathway of insulin signaling.

Coordinated phosphorylation of insulin receptor substrate-1 by glycogen synthase kinase-3 and protein kinase CβII in the diabetic fat tissue

2008 ◽  
Vol 294 (6) ◽  
pp. E1169-E1177 ◽  
Author(s):  
Ziva Liberman ◽  
Batya Plotkin ◽  
Tamar Tennenbaum ◽  
Hagit Eldar-Finkelman
Keyword(s):  
Protein Kinase ◽  
Insulin Receptor ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Insulin Receptor Substrate ◽  
Fat Tissue ◽  
Insulin Receptor Substrate 1 ◽  
Gsk 3Β

Serine/threonine phosphorylation of insulin receptor substrate-1 (IRS-1) is an important negative modulator of insulin signaling. Previously, we showed that glycogen synthase kinase-3 (GSK-3) phosphorylates IRS-1 at Ser332. However, the fact that GSK-3 requires prephosphorylation of its substrates suggested that Ser336 on IRS-1 was the “priming” site phosphorylated by an as yet unknown protein kinase. Here, we sought to identify this “priming kinase” and to examine the phosphorylation of IRS-1 at Ser336 and Ser332 in physiologically relevant animal models. Of several stimulators, only the PKC activator phorbol ester PMA enhanced IRS-1 phosphorylation at Ser336. Treatment with selective PKC inhibitors prevented this PMA effect and suggested that a conventional PKC was the priming kinase. Overexpression of PKCα or PKCβII isoforms in cells enhanced IRS-1 phosphorylation at Ser336 and Ser332, and in vitro kinase assays verified that these two kinases directly phosphorylated IRS-1 at Ser336. The expression level and activation state of PKCβII, but not PKCα, were remarkably elevated in the fat tissues of diabetic ob/ob mice and in high-fat diet-fed mice compared with that from lean animals. Elevated levels of PKCβII were also associated with enhanced phosphorylation of IRS-1 at Ser336/332 and elevated activity of GSK-3β. Finally, adenoviral mediated expression of PKCβII in adipocytes enhancedphosphorylation of IRS-1 at Ser336. Taken together, our results suggest that IRS-1 is sequentially phosphorylated by PKCβII and GSK-3 at Ser336 and Ser332. Furthermore, these data provide evidence for the physiological relevance of these phosphorylation events in the pathogenesis of insulin resistance in fat tissue.

scholarly journals Role of Substance P in the Regulation of Glucose Metabolism via Insulin Signaling-Associated Pathways

Endocrinology ◽  
2011 ◽  
Vol 152 (12) ◽  
pp. 4571-4580 ◽  
Author(s):  
Iordanes Karagiannides ◽  
Kyriaki Bakirtzi ◽  
Efi Kokkotou ◽  
Dimitris Stavrakis ◽  
Kara Gross Margolis ◽  
...  
Keyword(s):  
Weight Gain ◽  
Protein Kinase ◽  
Glucose Metabolism ◽  
Substance P ◽  
Insulin Receptor ◽  
Blood Levels ◽  
Insulin Receptor Substrate ◽  
Insulin Receptor Substrate 1 ◽  
Human Preadipocytes

Substance P (SP), encoded by the tachykinin 1 (Tac1) gene, is the most potent tachykinin ligand for the high-affinity neurokinin-1 receptor (NK-1R). We previously reported that NK-1R-deficient mice show less weight gain and reduced circulating levels of leptin and insulin in response to a high-fat diet (HFD) and demonstrated the presence of functional NK-1R in isolated human preadipocytes. Here we assessed the effects of SP on weight gain in response to HFD and determined glucose metabolism in Tac1-deficient (Tac1−/−) mice. The effect of SP on the expression of molecules that may predispose to reduced glucose uptake was also determined in isolated human mesenteric, omental, and sc preadipocytes. We show that although weight accumulation in response to HFD was similar between Tac1−/− mice and wild-type littermates, Tac1−/− mice demonstrated lower glucose and leptin and increased adiponectin blood levels and showed improved responses to insulin challenge after HFD. SP stimulated phosphorylation of c-Jun N-terminal kinase, protein kinase Cθ, mammalian target of rapamycin, and inhibitory serine insulin receptor substrate-1 phosphorylation in human preadipocytes in vitro. Preincubation of human mesenteric preadipocytes with the protein kinase Cθ pseudosubstrate inhibitor reduced insulin receptor substrate 1 phosphorylation in response to SP. Lastly, SP also induced insulin receptor substrate-1 phosphorylation in mature human sc adipocytes. Our results demonstrate an important role for SP in adipose tissue responses and obesity-associated pathologies. These novel SP effects on molecules that enhance insulin resistance at the adipocyte level may reflect an important role for this peptide in the pathophysiology of type 2 diabetes.

Changes in tyrosine phosphorylation of insulin receptor and insulin receptor substrate-1 (IRS-1) and association of p85 subunit of phosphatidylinositol 3-kinase with IRS-1 after feeding in rat liver in vivo

1997 ◽  
Vol 154 (2) ◽  
pp. 267-273 ◽  
Author(s):  
Y Ito ◽  
M Ariga ◽  
S-I Takahashi ◽  
A Takenaka ◽  
T Hidaka ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Tyrosine Phosphorylation ◽  
Rat Liver ◽  
Insulin Receptor Substrate ◽  
Β Subunit ◽  
Phosphatidylinositol 3 Kinase ◽  
Insulin Receptor Substrate 1 ◽  
Insulin Receptor Tyrosine Kinase ◽  
Phosphatidylinositol 3

Abstract The binding of insulin to its receptor rapidly induces intrinsic insulin receptor tyrosine kinase activity, resulting in tyrosine phosphorylation of various cytosolic substrates, such as insulin receptor substrate-1 (IRS-1) which, in turn, associates with a p85 subunit of phosphatidylinositol 3-kinase (PI 3-kinase) followed by activation of this enzyme. In the present study, we have examined these early steps of insulin signalling in rat liver in vivo after food ingestion. After fasting for 22 h, a 12% casein diet was available ad libitum throughout the 8-h experimental period. Plasma insulin concentrations increased within 45 min after feeding, reached a maximum at 1·5 h and gradually decreased until 8 h. Autophosphorylation of the insulin receptor β-subunit in liver was detected even during fasting and increased about 1·5-fold at 1·5 h after feeding. Basal tyrosine phosphorylation of IRS-1 was detectable during starvation, increased about twofold at 3 h after feeding and levels were maintained until 8 h. The content of the p85 subunit of PI 3-kinase associated with IRS-1 also increased after feeding in parallel with the changes in tyrosine phosphorylation of IRS-1. Because tyrosine phosphorylation of the insulin receptor β-subunit and IRS-1 and the association of the p85 subunit of PI 3-kinase with IRS-1 in liver were closely correlated with the changes in the plasma concentration of insulin, we concluded that endogenous insulin secreted in response to eating caused these insulin-dependent intracellular changes in the liver. Journal of Endocrinology (1997) 154, 267–273

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