Role of Akt/PKB and PFKFB isoenzymes in the control of glycolysis, cell proliferation and protein synthesis in mitogen-stimulated thymocytes
| Autor: | Louis Hue, Ramon Bartrons, Didier Vertommen, Marie-Agnès Gueuning, Pierre Coulie, Manuel Johanns, Laura Novellasdemunt, Laurent Bultot, Mark H. Rider, Amina Houddane |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
Phosphofructokinase-2 Gene Expression Jurkat cells 03 medical and health sciences Jurkat Cells 0302 clinical medicine Concanavalin A Animals Humans Phosphofructokinase 2 Phosphorylation Rats Wistar Protein kinase B Cells Cultured Cell Proliferation Ribosomal Protein S6 Thymocytes biology Cell growth Intracellular Signaling Peptides and Proteins Cell Biology PFKFB4 Phosphoproteins Molecular biology Cell biology Rats 030104 developmental biology 030220 oncology & carcinogenesis Ribosomal protein s6 Protein Biosynthesis biology.protein Female Carrier Proteins Glycolysis Heterocyclic Compounds 3-Ring Proto-Oncogene Proteins c-akt |
| Zdroj: | Cellular signalling. 34 |
| ISSN: | 1873-3913 |
| Popis: | Proliferating cells depend on glycolysis mainly to supply precursors for macromolecular synthesis. Fructose 2,6-bisphosphate (Fru-2,6-P2) is the most potent positive allosteric effector of 6-phosphofructo-1-kinase (PFK-1), and hence of glycolysis. Mitogen stimulation of rat thymocytes with concanavalin A (ConA) led to time-dependent increases in lactate accumulation (6-fold), Fru-2,6-P2 content (4-fold), 6-phosphofructo-2-kinase (PFK-2)/fructose-2,6-bisphosphatase isoenzyme 3 and 4 (PFKFB3 and PFKFB4) protein levels (~2-fold and ~15-fold, respectively) and rates of cell proliferation (~40-fold) and protein synthesis (10-fold) after 68h of incubation compared with resting cells. After 54h of ConA stimulation, PFKFB3 mRNA levels were 45-fold higher than those of PFKFB4 mRNA. Although PFKFB3 could be phosphorylated at Ser461 by protein kinase B (PKB) in vitro leading to PFK-2 activation, PFKFB3 Ser461 phosphorylation was barely detectable in resting cells and only increased slightly in ConA-stimulated cells. On the other hand, PFKFB3 and PFKFB4 mRNA levels were decreased (90% and 70%, respectively) by exposure of ConA-stimulated cells to low doses of PKB inhibitor (MK-2206), suggesting control of expression of the two PFKFB isoenzymes by PKB. Incubation of thymocytes with ConA resulted in increased expression and phosphorylation of the translation factors eukaryotic initiation factor-4E-binding protein-1 (4E-BP1) and ribosomal protein S6 (rpS6). Treatment of ConA-stimulated thymocytes with PFK-2 inhibitor (3PO) or MK-2206 led to significant decreases in Fru-2,6-P2 content, medium lactate accumulation and rates of cell proliferation and protein synthesis. These data were confirmed by using siRNA knockdown of PFKFB3, PFKFB4 and PKB α/β in the more easily transfectable Jurkat E6-1 cell line. The findings suggest that increased PFKFB3 and PFKFB4 expression, but not increased PFKFB3 Ser461 phosphorylation, plays a role in increasing glycolysis in mitogen-stimulated thymocytes and implicate PKB in the upregulation of PFKFB3 and PFKFB4. The results also support a role for Fru-2,6-P2 in coupling glycolysis to cell proliferation and protein synthesis in this model. |
| Databáze: | OpenAIRE |
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