Is stimulation of class-I phosphatidylinositol 3-kinase activity by insulin sufficient to activate pathways involved in glucose metabolism

1997 ◽  
Vol 25 (3) ◽  
pp. 978-981 ◽  
Author(s):  
P. R. Shepherd ◽  
K. Siddle ◽  
B. T. Navé
Keyword(s):  
Glucose Metabolism ◽  
Kinase Activity ◽  
Class I ◽  
Phosphatidylinositol 3 Kinase ◽  
Stimulation Of ◽  
Phosphatidylinositol 3

scholarly journals Phosphatidylinositol 3-Kinase Activity Is Critical for Glucose Metabolism and Embryo Survival in Murine Blastocysts

2005 ◽  
Vol 281 (9) ◽  
pp. 6010-6019 ◽  
Author(s):  
Joan K. Riley ◽  
Mary O. Carayannopoulos ◽  
Amanda H. Wyman ◽  
Maggie Chi ◽  
Kelle H. Moley
Keyword(s):  
Glucose Metabolism ◽  
Kinase Activity ◽  
Phosphatidylinositol 3 Kinase ◽  
Embryo Survival ◽  
Phosphatidylinositol 3

Long-chain n-3 polyunsaturated fatty acids dissociate phosphorylation of Akt from phosphatidylinositol 3′-kinase activity in rats

2007 ◽  
Vol 292 (4) ◽  
pp. E1223-E1230 ◽  
Author(s):  
Christelle Le Foll ◽  
Charlotte Corporeau ◽  
Valérie Le Guen ◽  
Jean-Paul Gouygou ◽  
Jean-Pascal Bergé ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Glucose Metabolism ◽  
Polyunsaturated Fatty Acids ◽  
Kinase Activity ◽  
Control Diet ◽  
Metabolizable Energy ◽  
Oral Glucose ◽  
Phosphatidylinositol 3 Kinase ◽  
Long Chain ◽  
Phosphatidylinositol 3

We examined whether a low amount of dietary long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) modulated phosphatidylinositol 3′-kinase (PI 3-kinase) activity and downstream Akt phosphorylation differently in normal or insulin-resistant rats. Rats were fed for 28 days with either a control diet containing 14.6% of metabolizable energy (ME) as peanut-rape oil (PR) or an n-3 diet where 4.9% of ME as PR was replaced by fish oil. Over the last 5 days, rats received 9‰ NaCl or dexamethasone (1 mg/kg). Insulin stimulation of both PI 3-kinase activity and Akt serine473 phosphorylation and modulation of GLUT4 content were studied in liver, muscle, and adipose tissue (AT). Glucose tolerance and insulin sensitivity were determined by an oral glucose challenge. In muscle and AT, LC n-3 PUFA abolished insulin-stimulated PI 3-kinase activity. These effects were not paralleled by defects in Akt serine473 phosphorylation, which was even increased in AT. Dexamethasone abolished insulin-stimulated PI 3-kinase activity in all tissues, whereas Akt serine473 phosphorylation was markedly reduced in muscle but unaltered in liver and AT. Such tissue-specific dissociating effects of LC n-3 PUFA on PI 3-kinase/Akt activation took place without alteration of glucose metabolism. Maintenance of a normal glucose metabolism by the n-3 diet despite abolition of PI 3-kinase activation was likely explained by a compensatory downstream Akt serine473 phosphorylation. The inability of LC n-3 PUFA to prevent insulin resistance by dexamethasone could result from the lack of such a dissociation.

scholarly journals Discordant Effects of Glucosamine on Insulin-stimulated Glucose Metabolism and Phosphatidylinositol 3-Kinase Activity

1999 ◽  
Vol 274 (44) ◽  
pp. 31312-31319 ◽  
Author(s):  
Meredith Hawkins ◽  
Meizhu Hu ◽  
Jinghua Yu ◽  
Howard Eder ◽  
Patricia Vuguin ◽  
...  
Keyword(s):  
Glucose Metabolism ◽  
Kinase Activity ◽  
Phosphatidylinositol 3 Kinase ◽  
Phosphatidylinositol 3

scholarly journals Reconstitution of cargo-induced LC3 lipidation in mammalian selective autophagy

2021 ◽  
Vol 7 (17) ◽  
pp. eabg4922
Author(s):  
Chunmei Chang ◽  
Xiaoshan Shi ◽  
Liv E. Jensen ◽  
Adam L. Yokom ◽  
Dorotea Fracchiolla ◽  
...  
Keyword(s):  
Complex I ◽  
Kinase Activity ◽  
Protein Aggregates ◽  
Class Iii ◽  
Phosphatidylinositol 3 Kinase ◽  
Giant Unilamellar Vesicles ◽  
Core Complex ◽  
Selective Autophagy ◽  
The Core ◽  
Stimulation Of

Selective autophagy of damaged mitochondria, protein aggregates, and other cargoes is essential for health. Cargo initiates phagophore biogenesis, which entails the conjugation of LC3 to phosphatidylethanolamine. Current models suggest that clustered ubiquitin chains on a cargo trigger a cascade from autophagic cargo receptors through the core complexes ULK1 and class III phosphatidylinositol 3-kinase complex I, WIPI2, and the ATG7, ATG3, and ATG12ATG5-ATG16L1 machinery of LC3 lipidation. This was tested using giant unilamellar vesicles (GUVs), GST-Ub4 as a model cargo, the cargo receptors NDP52, TAX1BP1, and OPTN, and the autophagy core complexes. All three cargo receptors potently stimulated LC3 lipidation on GUVs. NDP52- and TAX1BP1-induced LC3 lipidation required all components, but not ULK1 kinase activity. However, OPTN bypassed the ULK1 requirement. Thus, cargo-dependent stimulation of LC3 lipidation is common to multiple autophagic cargo receptors, yet the details of core complex engagement vary between the different receptors.

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