2014
Miller, Michelle S; Schmidt-Kittler, Oleg; Bolduc, David M; Brower, Evan T; Chaves-Moreira, Daniele; Allaire, Marc; Kinzler, Kenneth W; Jennings, Ian G; Thompson, Philip E; Cole, Philip A; Amzel, L Mario; Vogelstein, Bert; Gabelli, Sandra B
Structural basis of nSH2 regulation and lipid binding in PI3Kα Journal Article
In: Oncotarget, vol. 5, no. 14, pp. 5198-208, 2014, ISSN: 1949-2553.
Abstract | Links | BibTeX | Tags: Amino Acid Sequence, Animals, Binding Sites, Boron Compounds, Models, Molecular, Molecular Sequence Data, Phosphatidylinositol 3-Kinases, Protein Binding, Protein Conformation, Sf9 Cells, Signal Transduction, Spodoptera, src Homology Domains
@article{1299980,
title = {Structural basis of nSH2 regulation and lipid binding in PI3Kα},
author = {Michelle S Miller and Oleg Schmidt-Kittler and David M Bolduc and Evan T Brower and Daniele Chaves-Moreira and Marc Allaire and Kenneth W Kinzler and Ian G Jennings and Philip E Thompson and Philip A Cole and L Mario Amzel and Bert Vogelstein and Sandra B Gabelli},
doi = {10.18632/oncotarget.2263},
issn = {1949-2553},
year = {2014},
date = {2014-07-01},
journal = {Oncotarget},
volume = {5},
number = {14},
pages = {5198-208},
abstract = {We report two crystal structures of the wild-type phosphatidylinositol 3-kinase α (PI3Kα) heterodimer refined to 2.9 Å and 3.4 Å resolution: the first as the free enzyme, the second in complex with the lipid substrate, diC4-PIP$_2$, respectively. The first structure shows key interactions of the N-terminal SH2 domain (nSH2) and iSH2 with the activation loop that suggest a mechanism by which the enzyme is inhibited in its basal state. In the second structure, the lipid substrate binds in a positively charged pocket adjacent to the ATP-binding site, bordered by the P-loop, the activation loop and the iSH2 domain. An additional lipid-binding site was identified at the interface of the ABD, iSH2 and kinase domains. The ability of PI3Kα to bind an additional PIP$_2$ molecule was confirmed in vitro by fluorescence quenching experiments. The crystal structures reveal key differences in the way the nSH2 domain interacts with wild-type p110α and with the oncogenic mutant p110αH1047R. Increased buried surface area and two unique salt-bridges observed only in the wild-type structure suggest tighter inhibition in the wild-type PI3Kα than in the oncogenic mutant. These differences may be partially responsible for the increased basal lipid kinase activity and increased membrane binding of the oncogenic mutant.},
keywords = {Amino Acid Sequence, Animals, Binding Sites, Boron Compounds, Models, Molecular, Molecular Sequence Data, Phosphatidylinositol 3-Kinases, Protein Binding, Protein Conformation, Sf9 Cells, Signal Transduction, Spodoptera, src Homology Domains},
pubstate = {published},
tppubtype = {article}
}
We report two crystal structures of the wild-type phosphatidylinositol 3-kinase α (PI3Kα) heterodimer refined to 2.9 Å and 3.4 Å resolution: the first as the free enzyme, the second in complex with the lipid substrate, diC4-PIP$_2$, respectively. The first structure shows key interactions of the N-terminal SH2 domain (nSH2) and iSH2 with the activation loop that suggest a mechanism by which the enzyme is inhibited in its basal state. In the second structure, the lipid substrate binds in a positively charged pocket adjacent to the ATP-binding site, bordered by the P-loop, the activation loop and the iSH2 domain. An additional lipid-binding site was identified at the interface of the ABD, iSH2 and kinase domains. The ability of PI3Kα to bind an additional PIP$_2$ molecule was confirmed in vitro by fluorescence quenching experiments. The crystal structures reveal key differences in the way the nSH2 domain interacts with wild-type p110α and with the oncogenic mutant p110αH1047R. Increased buried surface area and two unique salt-bridges observed only in the wild-type structure suggest tighter inhibition in the wild-type PI3Kα than in the oncogenic mutant. These differences may be partially responsible for the increased basal lipid kinase activity and increased membrane binding of the oncogenic mutant.
0000
Cao, Jia; Peng, Jinghua; An, Hongying; He, Qiyi; Boronina, Tatiana; Guo, Shaodong; White, Morris F; Cole, Philip A; He, Ling
Endotoxemia-mediated activation of acetyltransferase P300 impairs insulin signaling in obesity Journal Article
In: Nat Commun, vol. 8, no. 1, pp. 131, 0000, ISSN: 2041-1723.
Abstract | Links | BibTeX | Tags: Animals, Cell Line, E1A-Associated p300 Protein, Endoplasmic Reticulum Stress, Endotoxemia, Gene Expression Profiling, Immunoblotting, Inbred C57BL, Insulin, Insulin Resistance, Lipopolysaccharides, Liver, Male, Membrane Proteins, Mice, Obese, Obesity, Protein-Serine-Threonine Kinases, Receptor, Signal Transduction, Tumor, X-Box Binding Protein 1
@article{1299941,
title = {Endotoxemia-mediated activation of acetyltransferase P300 impairs insulin signaling in obesity},
author = {Jia Cao and Jinghua Peng and Hongying An and Qiyi He and Tatiana Boronina and Shaodong Guo and Morris F White and Philip A Cole and Ling He},
doi = {10.1038/s41467-017-00163-w},
issn = {2041-1723},
journal = {Nat Commun},
volume = {8},
number = {1},
pages = {131},
abstract = {Diabetes and obesity are characterized by insulin resistance and chronic low-grade inflammation. An elevated plasma concentration of lipopolysaccharide (LPS) caused by increased intestinal permeability during diet-induced obesity promotes insulin resistance in mice. Here, we show that LPS induces endoplasmic reticulum (ER) stress and protein levels of P300, an acetyltransferase involved in glucose production. In high-fat diet fed and genetically obese ob/ob mice, P300 translocates from the nucleus into the cytoplasm of hepatocytes. We also demonstrate that LPS activates the transcription factor XBP1 via the ER stress sensor IRE1, resulting in the induction of P300 which, in turn, acetylates IRS1/2, inhibits its association with the insulin receptor, and disrupts insulin signaling. Pharmacological inhibition of P300 acetyltransferase activity by a specific inhibitor improves insulin sensitivity and decreases hyperglycemia in obese mice. We suggest that P300 acetyltransferase activity may be a promising therapeutic target for the treatment of obese patients.Elevated plasma LPS levels have been associated with insulin resistance. Here Cao et al. show that LPS induces ER stress and P300 activity via the XBP1/IRE1 pathway. P300 acetylates IRS1/2 and inhibits its binding with the insulin receptor. The consequent impairment of insulin signaling can be rescued by pharmacological inhibition of P300.},
keywords = {Animals, Cell Line, E1A-Associated p300 Protein, Endoplasmic Reticulum Stress, Endotoxemia, Gene Expression Profiling, Immunoblotting, Inbred C57BL, Insulin, Insulin Resistance, Lipopolysaccharides, Liver, Male, Membrane Proteins, Mice, Obese, Obesity, Protein-Serine-Threonine Kinases, Receptor, Signal Transduction, Tumor, X-Box Binding Protein 1},
pubstate = {published},
tppubtype = {article}
}
Diabetes and obesity are characterized by insulin resistance and chronic low-grade inflammation. An elevated plasma concentration of lipopolysaccharide (LPS) caused by increased intestinal permeability during diet-induced obesity promotes insulin resistance in mice. Here, we show that LPS induces endoplasmic reticulum (ER) stress and protein levels of P300, an acetyltransferase involved in glucose production. In high-fat diet fed and genetically obese ob/ob mice, P300 translocates from the nucleus into the cytoplasm of hepatocytes. We also demonstrate that LPS activates the transcription factor XBP1 via the ER stress sensor IRE1, resulting in the induction of P300 which, in turn, acetylates IRS1/2, inhibits its association with the insulin receptor, and disrupts insulin signaling. Pharmacological inhibition of P300 acetyltransferase activity by a specific inhibitor improves insulin sensitivity and decreases hyperglycemia in obese mice. We suggest that P300 acetyltransferase activity may be a promising therapeutic target for the treatment of obese patients.Elevated plasma LPS levels have been associated with insulin resistance. Here Cao et al. show that LPS induces ER stress and P300 activity via the XBP1/IRE1 pathway. P300 acetylates IRS1/2 and inhibits its binding with the insulin receptor. The consequent impairment of insulin signaling can be rescued by pharmacological inhibition of P300.