Identification of Ser1275 and Ser1309 as Autophosphorylation Sites of the Human Insulin Receptor in Intact Cells

Tennagels, Norbert; Telting, Darryl; Parvaresch, Susan; Maassen, Jennifer; Klein, Helmut W.

doi:10.1006/bbrc.2001.4589

Cited by 7 publications

(6 citation statements)

References 46 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, under these conditions a decrease in Ser phosphorylation of IR was detected, a situation that also favours Tyr phosphorylation of IR, indicating the possibility of an additional extragenic mechanism. It has been proposed that the kinase domain of IR acts as a dual specificity kinase, making phosphorylation of its own Ser and Tyr residues possible [35], as we detected in brown adipocytes. Moreover, rosiglitazone could modulate insulin signalling by acting through phosphatases at the level of the IR.…”

Section: Discussionsupporting

confidence: 63%

Rosiglitazone produces insulin sensitisation by increasing expression of the insulin receptor and its tyrosine kinase activity in brown adipocytes

2003

View full text Add to dashboard Cite

show abstract

Section: Discussionsupporting

confidence: 63%

Rosiglitazone produces insulin sensitisation by increasing expression of the insulin receptor and its tyrosine kinase activity in brown adipocytes

2003

View full text Add to dashboard Cite

show abstract

“…Classically, GRK2 activation leads to phosphorylation of GPCRs on serine/threonine residues and subsequent receptor desensitization (24). Increased Ser phosphorylation of the insulin receptor causes a simultaneous decrease in Tyr phosphorylation of insulin receptor and thus a decrease in receptor activity (25,26). Therefore, we anticipated that the GRK2 depletion would reduce serine phosphorylation of the insulin receptor, enhance Tyr phosphorylation of the insulin receptor, and enhance insulin receptor signaling.…”

Section: Discussionmentioning

confidence: 99%

GRK2 Negatively Regulates Glycogen Synthesis in Mouse Liver FL83B Cells

Shahid

Hussain

2007

Journal of Biological Chemistry

View full text Add to dashboard Cite

G-protein-coupled receptor (GPCR) kinases (GRKs) are serine/threonine kinases that desensitize agonist-occupied classical GPCRs. Although the insulin receptor (IR) is a tyrosine kinase receptor, the IR also couples to G-proteins and utilizes G-protein signaling components. The present study was designed to test the hypothesis that GRK2 negatively regulates IR signaling. FL83B cells, derived from mouse liver, were treated with insulin and membrane translocation of GRK2 was determined using immunofluoresecence and Western blotting. Insulin caused an increase in the translocation of GRK-2 from cytosol to the plasma membrane. To determine the role of GRK2 in IR signaling, GRK2 was selectively down-regulated (ϳby 90%) in FL83B cells using a small interfering RNA technique. The primary biological effect of insulin is maintenance of glucose homeostasis. The effects of insulin are mediated by binding to the insulin receptor, a member of the tyrosine kinase receptor family (1). The insulin receptor is a heterotetrameric receptor, consisting of two extracellular ␣ and two transmembrane ␤ subunits (2). Insulin binding to the ␣-subunit of insulin receptor causes autophosphorylation of the ␤-subunit at specific tyrosine residues (3). Autophosphorylation of the ␤-subunit increases the tyrosine kinase activity of the receptor toward other protein substrates, resulting in the tyrosine phosphorylation of a family of insulin receptor substrate proteins including IRS1, 2 IRS2, and Shc. The IRS proteins serve as docking proteins for other intracellular proteins containing Src homology 2 domains such as phosphatidylinositol 3-kinase (PI 3-kinase) and Grb2. The binding of these proteins to IRS proteins transmits the signal downstream, leading to the metabolic and mitogenic effects of insulin (4). For example, the interaction of phosphorylated IRS1/2 with PI 3-kinase leads to activation of protein kinase B/Akt, producing many effects such as GLUT4 translocation, protein synthesis, and inactivation of glycogen synthase kinase 3 (GSK3). The GSK3, a serine/threonine kinase, phosphorylates glycogen synthase and inactivates it. As glycogen synthase is a rate-limiting enzyme in glycogen synthesis, inactivation of GSK3 by insulin removes the inhibitory effect of GSK3 on glycogen synthase and leads to increased glycogen synthesis (5-7).In addition to signaling via its tyrosine kinase activity, the insulin receptor also couples to the G-proteins G i and G q (8,9). This IR/G-protein coupling is required for some actions of insulin. For example, insulin resistance develops in adipocytes when G␣ i is down-regulated (10). Moreover, in 3T3L1 adipocytes IR signaling via G␣ q/11 is required for insulin-induced GLUT4 translocation (11). The signaling of receptors via G-proteins is regulated by G protein-coupled receptor kinases (GRKs), a family of serine/threonine kinases that participate in G protein-coupled receptor (GPCR) desensitization. GRK2 can produce GPCR desensitization either by phosphorylation-dependent or phosphorylation-independent mechan...

show abstract

“…We were also disappointed, but not surprised, that INSR T1161 phosphorylation was not observed in category III because of the low abundance of the INSR (observation of this site in our previous work required two-step isolation and immunoprecipitation of the INSR) (8). The INSR phosphopeptides that were observed in category V are autophosphorylation events and are not associated with any known function (29,30).…”

Section: Investigation Of Hfd-induced Insulin Resistance By Phosphoprmentioning

confidence: 93%

PKCε contributes to lipid-induced insulin resistance through cross talk with p70S6K and through previously unknown regulators of insulin signaling

Gassaway

Petersen

Surovtseva

et al. 2018

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Insulin resistance drives the development of type 2 diabetes (T2D). In liver, diacylglycerol (DAG) is a key mediator of lipid-induced insulin resistance. DAG activates protein kinase C ε (PKCε), which phosphorylates and inhibits the insulin receptor. In rats, a 3-day high-fat diet produces hepatic insulin resistance through this mechanism, and knockdown of hepatic PKCε protects against high-fat diet-induced hepatic insulin resistance. Here, we employed a systems-level approach to uncover additional signaling pathways involved in high-fat diet-induced hepatic insulin resistance. We used quantitative phosphoproteomics to map global in vivo changes in hepatic protein phosphorylation in chow-fed, high-fat-fed, and high-fat-fed with PKCε knockdown rats to distinguish the impact of lipid- and PKCε-induced protein phosphorylation. This was followed by a functional siRNA-based screen to determine which dynamically regulated phosphoproteins may be involved in canonical insulin signaling. Direct PKCε substrates were identified by motif analysis of phosphoproteomics data and validated using a large-scale in vitro kinase assay. These substrates included the p70S6K substrates RPS6 and IRS1, which suggested cross talk between PKCε and p70S6K in high-fat diet-induced hepatic insulin resistance. These results identify an expanded set of proteins through which PKCε may drive high-fat diet-induced hepatic insulin resistance that may direct new therapeutic approaches for T2D.

show abstract

Identification of Ser1275 and Ser1309 as Autophosphorylation Sites of the Human Insulin Receptor in Intact Cells

Cited by 7 publications

References 46 publications

Rosiglitazone produces insulin sensitisation by increasing expression of the insulin receptor and its tyrosine kinase activity in brown adipocytes

Rosiglitazone produces insulin sensitisation by increasing expression of the insulin receptor and its tyrosine kinase activity in brown adipocytes

GRK2 Negatively Regulates Glycogen Synthesis in Mouse Liver FL83B Cells

PKCε contributes to lipid-induced insulin resistance through cross talk with p70S6K and through previously unknown regulators of insulin signaling

Contact Info

Product

Resources

About