Black, Hannah L, Livingstone, Rachel, Mastick, Cynthia C et al. (9 more authors) (2022) Knockout of syntaxin-4 in 3T3-L1 adipocytes reveals new insight into GLUT4 trafficking and adiponectin secretion. Journal of Cell Science. jcs258375. ISSN 0021-9533
Abstract
Adipocytes are key to metabolic regulation, exhibiting insulin-stimulated glucose transport that is underpinned by the insulin-stimulated delivery of glucose transporter type 4 (SLC2A4, also known and hereafter referred to as GLUT4)-containing vesicles to the plasma membrane where they dock and fuse, and increase cell surface GLUT4 levels. Adipocytokines, such as adiponectin, are secreted via a similar mechanism. 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 insulin-stimulated 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. This article has an associated First Person interview with Hannah L. Black and Rachel Livingstone, joint first authors of the paper.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2022. Published by The Company of Biologists Ltd. |
Keywords: | 3T3 Cells,3T3-L1 Cells,Adipocytes/metabolism,Adiponectin/genetics,Animals,Cell Membrane/metabolism,Glucose Transporter Type 4/genetics,Humans,Insulin/metabolism,Mice,Qa-SNARE Proteins/genetics |
Dates: |
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Institution: | The University of York |
Academic Units: | The University of York > Faculty of Sciences (York) > Biology (York) |
Depositing User: | Pure (York) |
Date Deposited: | 06 Jun 2022 13:00 |
Last Modified: | 16 Oct 2024 18:28 |
Published Version: | https://doi.org/10.1242/jcs.258375 |
Status: | Published |
Refereed: | Yes |
Identification Number: | 10.1242/jcs.258375 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:187681 |