Regulation of insulin-stimulated GLUT4 translocation by Munc18c in 3T3L1 adipocytes

Debbie C. Thurmond, Brian P. Ceresa, Shuichi Okada, Jeffrey S. Elmendorf, Kenneth Coker, Jeffrey E. Pessin

Research output: Contribution to journalArticle

196 Citations (Scopus)

Abstract

Insulin stimulates glucose transporter (GLUT) 4 vesicle translocation from intracellular storage sites to the plasma membrane in 3T3L1 adipocytes through a VAMP2- and syntaxin 4-dependent mechanism. We have observed that Munc18c, a mammalian homolog of the yeast syntaxin-binding protein n-Sec1p, competed for the binding of VAMP2 to syntaxin 4. Consistent with an inhibitory function for Munc18c, expression of Munc18c, but not the related Munc18b isoform, prevented the insulin stimulation of GLUT4 and IRAP/vp165 translocation to the plasma membrane without any significant effect on GLUT1 trafficking. As expected, overexpressed Munc18c was found to co- immunoprecipitate with syntaxin 4 in the basal state. However, these complexes were found to dissociate upon insulin stimulation. Furthermore, endogenous Munc18c was predominantly localized to the plasma membrane and its distribution was not altered by insulin stimulation. Although expression of enhanced green fluorescent protein-Munc18c primarily resulted in a dispersed cytosolic distribution, co-expression with syntaxin 4 resulted in increased localization to the plasma membrane. Together, these data suggest that Munc18c inhibits the docking/fusion of GLUT4-containing vesicles by blocking the binding of VAMP2 to syntaxin 4. Insulin relieves this inhibition by inducing the dissociation of Munc18c from syntaxin 4 and by sequestering Munc18c to an alternative plasma membrane binding site.

Original languageEnglish (US)
Pages (from-to)33876-33883
Number of pages8
JournalJournal of Biological Chemistry
Volume273
Issue number50
DOIs
StatePublished - Dec 11 1998
Externally publishedYes

Fingerprint

Qa-SNARE Proteins
Adipocytes
Cell membranes
Insulin
Vesicle-Associated Membrane Protein 2
Cell Membrane
Fungal Proteins
Facilitative Glucose Transport Proteins
Yeast
Carrier Proteins
Protein Isoforms
Fusion reactions
Binding Sites

ASJC Scopus subject areas

  • Biochemistry

Cite this

Regulation of insulin-stimulated GLUT4 translocation by Munc18c in 3T3L1 adipocytes. / Thurmond, Debbie C.; Ceresa, Brian P.; Okada, Shuichi; Elmendorf, Jeffrey S.; Coker, Kenneth; Pessin, Jeffrey E.

In: Journal of Biological Chemistry, Vol. 273, No. 50, 11.12.1998, p. 33876-33883.

Research output: Contribution to journalArticle

Thurmond, Debbie C. ; Ceresa, Brian P. ; Okada, Shuichi ; Elmendorf, Jeffrey S. ; Coker, Kenneth ; Pessin, Jeffrey E. / Regulation of insulin-stimulated GLUT4 translocation by Munc18c in 3T3L1 adipocytes. In: Journal of Biological Chemistry. 1998 ; Vol. 273, No. 50. pp. 33876-33883.
@article{c4627c015146489d83349755627b578b,
title = "Regulation of insulin-stimulated GLUT4 translocation by Munc18c in 3T3L1 adipocytes",
abstract = "Insulin stimulates glucose transporter (GLUT) 4 vesicle translocation from intracellular storage sites to the plasma membrane in 3T3L1 adipocytes through a VAMP2- and syntaxin 4-dependent mechanism. We have observed that Munc18c, a mammalian homolog of the yeast syntaxin-binding protein n-Sec1p, competed for the binding of VAMP2 to syntaxin 4. Consistent with an inhibitory function for Munc18c, expression of Munc18c, but not the related Munc18b isoform, prevented the insulin stimulation of GLUT4 and IRAP/vp165 translocation to the plasma membrane without any significant effect on GLUT1 trafficking. As expected, overexpressed Munc18c was found to co- immunoprecipitate with syntaxin 4 in the basal state. However, these complexes were found to dissociate upon insulin stimulation. Furthermore, endogenous Munc18c was predominantly localized to the plasma membrane and its distribution was not altered by insulin stimulation. Although expression of enhanced green fluorescent protein-Munc18c primarily resulted in a dispersed cytosolic distribution, co-expression with syntaxin 4 resulted in increased localization to the plasma membrane. Together, these data suggest that Munc18c inhibits the docking/fusion of GLUT4-containing vesicles by blocking the binding of VAMP2 to syntaxin 4. Insulin relieves this inhibition by inducing the dissociation of Munc18c from syntaxin 4 and by sequestering Munc18c to an alternative plasma membrane binding site.",
author = "Thurmond, {Debbie C.} and Ceresa, {Brian P.} and Shuichi Okada and Elmendorf, {Jeffrey S.} and Kenneth Coker and Pessin, {Jeffrey E.}",
year = "1998",
month = "12",
day = "11",
doi = "10.1074/jbc.273.50.33876",
language = "English (US)",
volume = "273",
pages = "33876--33883",
journal = "Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "American Society for Biochemistry and Molecular Biology Inc.",
number = "50",

}

TY - JOUR

T1 - Regulation of insulin-stimulated GLUT4 translocation by Munc18c in 3T3L1 adipocytes

AU - Thurmond, Debbie C.

AU - Ceresa, Brian P.

AU - Okada, Shuichi

AU - Elmendorf, Jeffrey S.

AU - Coker, Kenneth

AU - Pessin, Jeffrey E.

PY - 1998/12/11

Y1 - 1998/12/11

N2 - Insulin stimulates glucose transporter (GLUT) 4 vesicle translocation from intracellular storage sites to the plasma membrane in 3T3L1 adipocytes through a VAMP2- and syntaxin 4-dependent mechanism. We have observed that Munc18c, a mammalian homolog of the yeast syntaxin-binding protein n-Sec1p, competed for the binding of VAMP2 to syntaxin 4. Consistent with an inhibitory function for Munc18c, expression of Munc18c, but not the related Munc18b isoform, prevented the insulin stimulation of GLUT4 and IRAP/vp165 translocation to the plasma membrane without any significant effect on GLUT1 trafficking. As expected, overexpressed Munc18c was found to co- immunoprecipitate with syntaxin 4 in the basal state. However, these complexes were found to dissociate upon insulin stimulation. Furthermore, endogenous Munc18c was predominantly localized to the plasma membrane and its distribution was not altered by insulin stimulation. Although expression of enhanced green fluorescent protein-Munc18c primarily resulted in a dispersed cytosolic distribution, co-expression with syntaxin 4 resulted in increased localization to the plasma membrane. Together, these data suggest that Munc18c inhibits the docking/fusion of GLUT4-containing vesicles by blocking the binding of VAMP2 to syntaxin 4. Insulin relieves this inhibition by inducing the dissociation of Munc18c from syntaxin 4 and by sequestering Munc18c to an alternative plasma membrane binding site.

AB - Insulin stimulates glucose transporter (GLUT) 4 vesicle translocation from intracellular storage sites to the plasma membrane in 3T3L1 adipocytes through a VAMP2- and syntaxin 4-dependent mechanism. We have observed that Munc18c, a mammalian homolog of the yeast syntaxin-binding protein n-Sec1p, competed for the binding of VAMP2 to syntaxin 4. Consistent with an inhibitory function for Munc18c, expression of Munc18c, but not the related Munc18b isoform, prevented the insulin stimulation of GLUT4 and IRAP/vp165 translocation to the plasma membrane without any significant effect on GLUT1 trafficking. As expected, overexpressed Munc18c was found to co- immunoprecipitate with syntaxin 4 in the basal state. However, these complexes were found to dissociate upon insulin stimulation. Furthermore, endogenous Munc18c was predominantly localized to the plasma membrane and its distribution was not altered by insulin stimulation. Although expression of enhanced green fluorescent protein-Munc18c primarily resulted in a dispersed cytosolic distribution, co-expression with syntaxin 4 resulted in increased localization to the plasma membrane. Together, these data suggest that Munc18c inhibits the docking/fusion of GLUT4-containing vesicles by blocking the binding of VAMP2 to syntaxin 4. Insulin relieves this inhibition by inducing the dissociation of Munc18c from syntaxin 4 and by sequestering Munc18c to an alternative plasma membrane binding site.

UR - http://www.scopus.com/inward/record.url?scp=0032509214&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0032509214&partnerID=8YFLogxK

U2 - 10.1074/jbc.273.50.33876

DO - 10.1074/jbc.273.50.33876

M3 - Article

VL - 273

SP - 33876

EP - 33883

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

SN - 0021-9258

IS - 50

ER -