Knockout of Syntaxin-4 in 3T3-L1 adipocytes reveals new insight into GLUT4 trafficking and adiponectin secretion

Black, H. L. et al. (2022) Knockout of Syntaxin-4 in 3T3-L1 adipocytes reveals new insight into GLUT4 trafficking and adiponectin secretion. Journal of Cell Science, 135(1), jcs258375. (doi: 10.1242/jcs.258375) (PMID:34859814) (PMCID:PMC8767277)

[img] Text
260528.pdf - Published Version
Available under License Creative Commons Attribution.

3MB

Abstract

Adipocytes are key to metabolic regulation, exhibiting insulin-stimulated glucose transport which is underpinned by the insulin-stimulated delivery of glucose transporter-4 (GLUT4)- containing vesicles to the plasma membrane where they dock and fuse increasing cell surface GLUT4 levels. Adipocytokines such as adiponectin are secreted via a similar mechanism. We used genome editing to knockout Syntaxin-4 a protein reported to mediate GLUT4-vesicle fusion with 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 HA-GLUT4-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.

Item Type:Articles
Additional Information:This work was supported by grants from Diabetes UK (15/0005246, 17/0005605, 17/0005724,18/0005847, 18/0005905 and 19/0005978 to GWG and/or NJB), the Novo Nordisk Research Foundation (to GWG, JRP and JGB). AG thanks the Lister Institute for a summer research stipend and the EPSRC for a PhD studentship (AG). Mal-T thanks the Government of Oman for a studentship. CCM thanks the University of Nevada, Reno for sabbatical support.
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Boyle, Dr James and Gould, Professor Gwyn and Livingstone, Dr Rachel and AL TOBI, Mohammed Nasser Rashid and Kioumourtzoglou, Mr Dimitrios and Petrie, Professor John and Stirrat, Mrs Laura
Authors: Black, H. L., Livingstone, R., Mastick, C. C., Al Tobi, M., Taylor, H., Geiser, A., Stirrat, L., Kioumourtzoglou, D., Petrie, J. R., Boyle, J. G., Bryant, N. J., and Gould, G. W.
College/School:College of Medical Veterinary and Life Sciences > Institute of Cardiovascular and Medical Sciences
College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
Journal Name:Journal of Cell Science
Publisher:Company of Biologists
ISSN:0021-9533
ISSN (Online):1477-9137
Published Online:03 December 2021
Copyright Holders:Copyright © 2021 The Company of Biologists Ltd
First Published:First published in Journal of Cell Science 135(1): jcs258375
Publisher Policy:Reproduced under a Creative Commons License

University Staff: Request a correction | Enlighten Editors: Update this record

Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
173377How does Cholesterol regulate insulin action in adipocytes?Gwyn GouldDiabetes UK (DIABETUK)15/0005246Institute of Molecular, Cell & Systems Biology
304626Insulin receptor phosphorylation of SNARE proteins at the plasma membrane?Gwyn GouldDiabetes UK (DIABETUK)18/0005905Institute of Molecular, Cell & Systems Biology