Autor: |
Black, Hannah L., Livingstone, Rachel, Mastick, Cynthia C., Al Tobi, Mohammed, Taylor, Holly, Geiser, Angéline, Stirrat, Laura, Kioumourtzoglou, Dimitrios, Petrie, John R., Boyle, James G., Bryant, Nia J., Gould, Gwyn W. |
Předmět: |
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Zdroj: |
Journal of Cell Science; Jul2024, Vol. 137 Issue 13, p1-10, 10p |
Abstrakt: |
Adipocytes are key to metabolic regulation, exhibiting insulinstimulated glucose transport that is underpinned by the insulinstimulated delivery of glucose transporter type 4 (SLC2A4, also known and hereafter referred to as GLUT4)-containing vesicles to the plasmamembranewhere they dock and fuse, and increase cell surface GLUT4 levels. Adipocytokines, such as adiponectin, are secreted via a similarmechanism.We used genome editing to knock out syntaxin-4, a protein reported to mediate fusion between GLUT4-containing vesicles and the plasma membrane in 3T3-L1 adipocytes. Syntaxin-4 knockout reduced insulin-stimulated glucose transport and adiponectin secretion by ~50% and reduced GLUT4 levels. Ectopic expression of haemagglutinin (HA)-tagged GLUT4 conjugated to GFP showed that syntaxin-4-knockout cells retain significant GLUT4 translocation capacity, demonstrating that syntaxin-4 is dispensable for insulinstimulated GLUT4 translocation. Analysis of recycling kinetics revealed only a modest reduction in the exocytic rate of GLUT4 in knockout cells, and little effect on endocytosis. These analyses demonstrate that syntaxin-4 is not always rate limiting for GLUT4 delivery to the cell surface. In sum, we show that syntaxin-4 knockout results in reduced insulin-stimulated glucose transport, depletion of cellular GLUT4 levels and inhibition of adiponectin secretion but has only modest effects on the translocation capacity of the cells. [ABSTRACT FROM AUTHOR] |
Databáze: |
Complementary Index |
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