Insulin-triggered repositioning of munc18c on syntaxin-4 in GLUT4 signalling
Insulin-triggered repositioning of munc18c on syntaxin-4 in GLUT4 signalling
One of the most important actions of insulin is the stimulation of the uptake of glucose into fat and muscle cells. Crucial to this response is the translocation of GLUT4 (glucose transporter-4) to the plasma membrane. The insulin-stimulated GLUT4 vesicle docking at the plasma membrane requires an interaction between VAMP-2 (vesicle-associated membrane protein-2) on the GLUT4 vesicle and syntaxin-4 in the plasma membrane. In the basal state, munc18c is thought to preclude GLUT4 vesicle docking by inhibiting this interaction.
Here, we have used FCS (fluorescence correlation spectroscopy) in single living cells to show that munc18c binds to syntaxin-4 in both the basal and insulin-stimulated states. We show that munc18c contains two binding sites for syntaxin-4, one of which is disrupted by insulin, while the other is activated by insulin. Insulin-triggered repositioning of munc18c on syntaxin-4 in this way in turn allows syntaxin-4 to adopt its ‘open’ conformation and bind VAMP-2, resulting in the docking of the GLUT4 vesicle at the cell surface. The results also demonstrate the utility of using FCS in intact single living cells to elucidate cell signalling events.
fluorescence correlation spectroscopy (FCS), glucose
transporter-4 (GLUT4), glucose uptake, insulin, munc18c, vesicle-associated membrane protein (VAMP)
255-260
Smithers, Natalie P.
63ead01b-6515-4f82-a963-884f572af872
Hodgkinson, Conrad P.
292cc7c3-b378-4911-8353-9a8c08a1c737
Cuttle, Matt
14c21805-5031-4b40-8699-8b08b93bdd59
Sale, Graham J.
81048025-7d8f-4218-969a-bf95ebf50b51
1 March 2008
Smithers, Natalie P.
63ead01b-6515-4f82-a963-884f572af872
Hodgkinson, Conrad P.
292cc7c3-b378-4911-8353-9a8c08a1c737
Cuttle, Matt
14c21805-5031-4b40-8699-8b08b93bdd59
Sale, Graham J.
81048025-7d8f-4218-969a-bf95ebf50b51
Smithers, Natalie P., Hodgkinson, Conrad P., Cuttle, Matt and Sale, Graham J.
(2008)
Insulin-triggered repositioning of munc18c on syntaxin-4 in GLUT4 signalling.
Biochemical Journal, 410 (2), .
(doi:10.1042/BJ20070802).
(PMID:17956227)
Abstract
One of the most important actions of insulin is the stimulation of the uptake of glucose into fat and muscle cells. Crucial to this response is the translocation of GLUT4 (glucose transporter-4) to the plasma membrane. The insulin-stimulated GLUT4 vesicle docking at the plasma membrane requires an interaction between VAMP-2 (vesicle-associated membrane protein-2) on the GLUT4 vesicle and syntaxin-4 in the plasma membrane. In the basal state, munc18c is thought to preclude GLUT4 vesicle docking by inhibiting this interaction.
Here, we have used FCS (fluorescence correlation spectroscopy) in single living cells to show that munc18c binds to syntaxin-4 in both the basal and insulin-stimulated states. We show that munc18c contains two binding sites for syntaxin-4, one of which is disrupted by insulin, while the other is activated by insulin. Insulin-triggered repositioning of munc18c on syntaxin-4 in this way in turn allows syntaxin-4 to adopt its ‘open’ conformation and bind VAMP-2, resulting in the docking of the GLUT4 vesicle at the cell surface. The results also demonstrate the utility of using FCS in intact single living cells to elucidate cell signalling events.
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e-pub ahead of print date: 24 October 2007
Published date: 1 March 2008
Keywords:
fluorescence correlation spectroscopy (FCS), glucose
transporter-4 (GLUT4), glucose uptake, insulin, munc18c, vesicle-associated membrane protein (VAMP)
Identifiers
Local EPrints ID: 160175
URI: http://eprints.soton.ac.uk/id/eprint/160175
ISSN: 1470-8728
PURE UUID: 587f85a1-149f-4160-b958-de19336b7c64
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Date deposited: 12 Jul 2010 09:23
Last modified: 14 Mar 2024 01:56
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Contributors
Author:
Natalie P. Smithers
Author:
Conrad P. Hodgkinson
Author:
Matt Cuttle
Author:
Graham J. Sale
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