The stimulatory action of tolbutamide on Ca2+-dependent exocytosis in pancreatic β cells is mediated by a 65-kDa mdr-like P-glycoprotein

S. Barg, E. Renstrom, P. O. Berggren, A. Bertorello, K. Bokvist, M. Braun, L. Eliasson, W. E. Holmes, M. Kohler, P. Rorsman, F. Thevenod

Research output: Contribution to journalArticle

67 Citations (Scopus)

Abstract

Intracellular application of the sulfonylurea tolbutamide during whole- cell patch-clamp recordings stimulated exocytosis >5-fold when applied at a cytoplasmic Ca2+ concentration of 0.17 μM. This effect was not detectable in the complete absence of cytoplasmic Ca2+ and when exocytosis was elicited by guanosine 5'-O-(3-thiotriphosphate) (GTPγS). The stimulatory action could be antagonized by the sulfonamide diazoxide, by the Cl-- channel blocker 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), by intracellular application of the antibody JSB1 [originally raised against a 170-kDa multidrug resistance (mdr) protein], and by tamoxifen (an inhibitor of the mdr- and volume-regulated Cl- channels). Immunocytochemistry and Western blot analyses revealed that JSB1 recognizes a 65-kDa protein in the secretory granules. This protein exhibited no detectable binding of sulfonylureas and is distinct from the 140-kDa sulfonylurea high-affinity sulfonylurea receptors also present in the granules. We conclude that (i) tolbutamide stimulates Ca2+-dependent exocytosis secondary to its binding to a 140-kDa high-affinity sulfonylurea receptor in the secretory granules; and (ii) a granular 65-kDa mdr-like protein mediates the action. The processes thus initiated culminate in the activation of a granular Cl- conductance. We speculate that the activation of granular Cl- fluxes promotes exocytosis (possibly by providing the energy required for membrane fusion) by inducing water uptake and an increased intragranular hydrostatic pressure.

Original languageEnglish
Pages (from-to)5539-5544
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume96
Issue number10
DOIs
StatePublished - May 11 1999
Externally publishedYes

Fingerprint

Tolbutamide
Exocytosis
Multiple Drug Resistance
P-Glycoprotein
Sulfonylurea Receptors
P-Glycoproteins
Secretory Vesicles
Guanosine 5'-O-(3-Thiotriphosphate)
Diazoxide
Membrane Fusion
Hydrostatic Pressure
Sulfonamides
Tamoxifen
Proteins
Western Blotting
Immunohistochemistry
Acids
Water
Antibodies

Keywords

  • ABC protein
  • Insulin
  • Sulfonyl urea receptor

ASJC Scopus subject areas

  • Genetics
  • General

Cite this

The stimulatory action of tolbutamide on Ca2+-dependent exocytosis in pancreatic β cells is mediated by a 65-kDa mdr-like P-glycoprotein. / Barg, S.; Renstrom, E.; Berggren, P. O.; Bertorello, A.; Bokvist, K.; Braun, M.; Eliasson, L.; Holmes, W. E.; Kohler, M.; Rorsman, P.; Thevenod, F.

In: Proceedings of the National Academy of Sciences of the United States of America, Vol. 96, No. 10, 11.05.1999, p. 5539-5544.

Research output: Contribution to journalArticle

Barg, S, Renstrom, E, Berggren, PO, Bertorello, A, Bokvist, K, Braun, M, Eliasson, L, Holmes, WE, Kohler, M, Rorsman, P & Thevenod, F 1999, 'The stimulatory action of tolbutamide on Ca2+-dependent exocytosis in pancreatic β cells is mediated by a 65-kDa mdr-like P-glycoprotein', Proceedings of the National Academy of Sciences of the United States of America, vol. 96, no. 10, pp. 5539-5544. https://doi.org/10.1073/pnas.96.10.5539
Barg, S. ; Renstrom, E. ; Berggren, P. O. ; Bertorello, A. ; Bokvist, K. ; Braun, M. ; Eliasson, L. ; Holmes, W. E. ; Kohler, M. ; Rorsman, P. ; Thevenod, F. / The stimulatory action of tolbutamide on Ca2+-dependent exocytosis in pancreatic β cells is mediated by a 65-kDa mdr-like P-glycoprotein. In: Proceedings of the National Academy of Sciences of the United States of America. 1999 ; Vol. 96, No. 10. pp. 5539-5544.
@article{21cf39810606465788a0d3fce7f0fb6c,
title = "The stimulatory action of tolbutamide on Ca2+-dependent exocytosis in pancreatic β cells is mediated by a 65-kDa mdr-like P-glycoprotein",
abstract = "Intracellular application of the sulfonylurea tolbutamide during whole- cell patch-clamp recordings stimulated exocytosis >5-fold when applied at a cytoplasmic Ca2+ concentration of 0.17 μM. This effect was not detectable in the complete absence of cytoplasmic Ca2+ and when exocytosis was elicited by guanosine 5'-O-(3-thiotriphosphate) (GTPγS). The stimulatory action could be antagonized by the sulfonamide diazoxide, by the Cl-- channel blocker 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), by intracellular application of the antibody JSB1 [originally raised against a 170-kDa multidrug resistance (mdr) protein], and by tamoxifen (an inhibitor of the mdr- and volume-regulated Cl- channels). Immunocytochemistry and Western blot analyses revealed that JSB1 recognizes a 65-kDa protein in the secretory granules. This protein exhibited no detectable binding of sulfonylureas and is distinct from the 140-kDa sulfonylurea high-affinity sulfonylurea receptors also present in the granules. We conclude that (i) tolbutamide stimulates Ca2+-dependent exocytosis secondary to its binding to a 140-kDa high-affinity sulfonylurea receptor in the secretory granules; and (ii) a granular 65-kDa mdr-like protein mediates the action. The processes thus initiated culminate in the activation of a granular Cl- conductance. We speculate that the activation of granular Cl- fluxes promotes exocytosis (possibly by providing the energy required for membrane fusion) by inducing water uptake and an increased intragranular hydrostatic pressure.",
keywords = "ABC protein, Insulin, Sulfonyl urea receptor",
author = "S. Barg and E. Renstrom and Berggren, {P. O.} and A. Bertorello and K. Bokvist and M. Braun and L. Eliasson and Holmes, {W. E.} and M. Kohler and P. Rorsman and F. Thevenod",
year = "1999",
month = "5",
day = "11",
doi = "10.1073/pnas.96.10.5539",
language = "English",
volume = "96",
pages = "5539--5544",
journal = "Proceedings of the National Academy of Sciences of the United States of America",
issn = "0027-8424",
number = "10",

}

TY - JOUR

T1 - The stimulatory action of tolbutamide on Ca2+-dependent exocytosis in pancreatic β cells is mediated by a 65-kDa mdr-like P-glycoprotein

AU - Barg, S.

AU - Renstrom, E.

AU - Berggren, P. O.

AU - Bertorello, A.

AU - Bokvist, K.

AU - Braun, M.

AU - Eliasson, L.

AU - Holmes, W. E.

AU - Kohler, M.

AU - Rorsman, P.

AU - Thevenod, F.

PY - 1999/5/11

Y1 - 1999/5/11

N2 - Intracellular application of the sulfonylurea tolbutamide during whole- cell patch-clamp recordings stimulated exocytosis >5-fold when applied at a cytoplasmic Ca2+ concentration of 0.17 μM. This effect was not detectable in the complete absence of cytoplasmic Ca2+ and when exocytosis was elicited by guanosine 5'-O-(3-thiotriphosphate) (GTPγS). The stimulatory action could be antagonized by the sulfonamide diazoxide, by the Cl-- channel blocker 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), by intracellular application of the antibody JSB1 [originally raised against a 170-kDa multidrug resistance (mdr) protein], and by tamoxifen (an inhibitor of the mdr- and volume-regulated Cl- channels). Immunocytochemistry and Western blot analyses revealed that JSB1 recognizes a 65-kDa protein in the secretory granules. This protein exhibited no detectable binding of sulfonylureas and is distinct from the 140-kDa sulfonylurea high-affinity sulfonylurea receptors also present in the granules. We conclude that (i) tolbutamide stimulates Ca2+-dependent exocytosis secondary to its binding to a 140-kDa high-affinity sulfonylurea receptor in the secretory granules; and (ii) a granular 65-kDa mdr-like protein mediates the action. The processes thus initiated culminate in the activation of a granular Cl- conductance. We speculate that the activation of granular Cl- fluxes promotes exocytosis (possibly by providing the energy required for membrane fusion) by inducing water uptake and an increased intragranular hydrostatic pressure.

AB - Intracellular application of the sulfonylurea tolbutamide during whole- cell patch-clamp recordings stimulated exocytosis >5-fold when applied at a cytoplasmic Ca2+ concentration of 0.17 μM. This effect was not detectable in the complete absence of cytoplasmic Ca2+ and when exocytosis was elicited by guanosine 5'-O-(3-thiotriphosphate) (GTPγS). The stimulatory action could be antagonized by the sulfonamide diazoxide, by the Cl-- channel blocker 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), by intracellular application of the antibody JSB1 [originally raised against a 170-kDa multidrug resistance (mdr) protein], and by tamoxifen (an inhibitor of the mdr- and volume-regulated Cl- channels). Immunocytochemistry and Western blot analyses revealed that JSB1 recognizes a 65-kDa protein in the secretory granules. This protein exhibited no detectable binding of sulfonylureas and is distinct from the 140-kDa sulfonylurea high-affinity sulfonylurea receptors also present in the granules. We conclude that (i) tolbutamide stimulates Ca2+-dependent exocytosis secondary to its binding to a 140-kDa high-affinity sulfonylurea receptor in the secretory granules; and (ii) a granular 65-kDa mdr-like protein mediates the action. The processes thus initiated culminate in the activation of a granular Cl- conductance. We speculate that the activation of granular Cl- fluxes promotes exocytosis (possibly by providing the energy required for membrane fusion) by inducing water uptake and an increased intragranular hydrostatic pressure.

KW - ABC protein

KW - Insulin

KW - Sulfonyl urea receptor

UR - http://www.scopus.com/inward/record.url?scp=0033545857&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0033545857&partnerID=8YFLogxK

U2 - 10.1073/pnas.96.10.5539

DO - 10.1073/pnas.96.10.5539

M3 - Article

C2 - 10318919

AN - SCOPUS:0033545857

VL - 96

SP - 5539

EP - 5544

JO - Proceedings of the National Academy of Sciences of the United States of America

JF - Proceedings of the National Academy of Sciences of the United States of America

SN - 0027-8424

IS - 10

ER -