Endofacial competitive inhibition of glucose transporter-4 intrinsic activity by the mitogen-activated protein kinase inhibitor SB203580

D Ribe, J Yang, S Patel, F O Koumanov, S W Cushman, G D Holman

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

The translocation of glucose transporter-4 (GLUT4) to the cell surface is a complex multistep process that involves movement of GLUT4 vesicles from a reservoir compartment, and docking and fusion of the vesicles with the plasma membrane. It has recently been proposed that a p38 mitogen-activated protein kinase ( MAPK)-dependent step may lead to intrinsic activation of the transporters exposed at the cell surface. In contrast to data obtained in muscle and adipocyte cell lines, we found that no insulin activation of p38 MAPK occurred in rat adipose cells. However, the p38 MAPK inhibitor SB203580 consistently inhibited transport activity after preincubation with the adipose cells. These apparently contradictory findings led us to hypothesize that the inhibitor may have a direct effect on the transport catalytic activity of GLUT4 that was independent of inhibition of the kinase. Kinetic analysis of 3-O-methyl-D-glucose transport activity revealed that SB203580 was a noncompetitive inhibitor of zero-trans ( substrate outside but not inside) transport, but was a competitive inhibitor of equilibrium-exchange ( substrate inside and outside) transport. This pattern of inhibition of GLUT4 was also observed with cytochalasin B. The pattern of inhibition is consistent with interaction at the endofacial surface, but not the exofacial surface of the transporter. Occupation of the endofacial substrate site reduces maximum velocity under zero-trans conditions, because return of the substrate site to the outside is blocked, and no substrate is present inside to displace the inhibitor. Under equilibrium-exchange conditions, internal substrate competitively displaces the inhibitor, and the transport K-m is increased.
Original languageEnglish
Pages (from-to)1713-1717
Number of pages5
JournalEndocrinology
Volume146
Issue number4
DOIs
Publication statusPublished - 2005

Fingerprint

Facilitative Glucose Transport Proteins
Protein Kinase Inhibitors
Mitogen-Activated Protein Kinases
p38 Mitogen-Activated Protein Kinases
3-O-Methylglucose
Cytochalasin B
Occupations
Adipocytes
Muscle Cells
Phosphotransferases
Cell Membrane
Insulin
Cell Line
SB 203580

Cite this

Endofacial competitive inhibition of glucose transporter-4 intrinsic activity by the mitogen-activated protein kinase inhibitor SB203580. / Ribe, D; Yang, J; Patel, S; Koumanov, F O; Cushman, S W; Holman, G D.

In: Endocrinology, Vol. 146, No. 4, 2005, p. 1713-1717.

Research output: Contribution to journalArticle

@article{cdbd6cff962b4b44957b62268cb365ea,
title = "Endofacial competitive inhibition of glucose transporter-4 intrinsic activity by the mitogen-activated protein kinase inhibitor SB203580",
abstract = "The translocation of glucose transporter-4 (GLUT4) to the cell surface is a complex multistep process that involves movement of GLUT4 vesicles from a reservoir compartment, and docking and fusion of the vesicles with the plasma membrane. It has recently been proposed that a p38 mitogen-activated protein kinase ( MAPK)-dependent step may lead to intrinsic activation of the transporters exposed at the cell surface. In contrast to data obtained in muscle and adipocyte cell lines, we found that no insulin activation of p38 MAPK occurred in rat adipose cells. However, the p38 MAPK inhibitor SB203580 consistently inhibited transport activity after preincubation with the adipose cells. These apparently contradictory findings led us to hypothesize that the inhibitor may have a direct effect on the transport catalytic activity of GLUT4 that was independent of inhibition of the kinase. Kinetic analysis of 3-O-methyl-D-glucose transport activity revealed that SB203580 was a noncompetitive inhibitor of zero-trans ( substrate outside but not inside) transport, but was a competitive inhibitor of equilibrium-exchange ( substrate inside and outside) transport. This pattern of inhibition of GLUT4 was also observed with cytochalasin B. The pattern of inhibition is consistent with interaction at the endofacial surface, but not the exofacial surface of the transporter. Occupation of the endofacial substrate site reduces maximum velocity under zero-trans conditions, because return of the substrate site to the outside is blocked, and no substrate is present inside to displace the inhibitor. Under equilibrium-exchange conditions, internal substrate competitively displaces the inhibitor, and the transport K-m is increased.",
author = "D Ribe and J Yang and S Patel and Koumanov, {F O} and Cushman, {S W} and Holman, {G D}",
note = "ID number: ISI:000227667400010",
year = "2005",
doi = "10.1210/en.2004-1294",
language = "English",
volume = "146",
pages = "1713--1717",
journal = "Endocrinology",
issn = "0013-7227",
publisher = "The Endocrine Society",
number = "4",

}

TY - JOUR

T1 - Endofacial competitive inhibition of glucose transporter-4 intrinsic activity by the mitogen-activated protein kinase inhibitor SB203580

AU - Ribe, D

AU - Yang, J

AU - Patel, S

AU - Koumanov, F O

AU - Cushman, S W

AU - Holman, G D

N1 - ID number: ISI:000227667400010

PY - 2005

Y1 - 2005

N2 - The translocation of glucose transporter-4 (GLUT4) to the cell surface is a complex multistep process that involves movement of GLUT4 vesicles from a reservoir compartment, and docking and fusion of the vesicles with the plasma membrane. It has recently been proposed that a p38 mitogen-activated protein kinase ( MAPK)-dependent step may lead to intrinsic activation of the transporters exposed at the cell surface. In contrast to data obtained in muscle and adipocyte cell lines, we found that no insulin activation of p38 MAPK occurred in rat adipose cells. However, the p38 MAPK inhibitor SB203580 consistently inhibited transport activity after preincubation with the adipose cells. These apparently contradictory findings led us to hypothesize that the inhibitor may have a direct effect on the transport catalytic activity of GLUT4 that was independent of inhibition of the kinase. Kinetic analysis of 3-O-methyl-D-glucose transport activity revealed that SB203580 was a noncompetitive inhibitor of zero-trans ( substrate outside but not inside) transport, but was a competitive inhibitor of equilibrium-exchange ( substrate inside and outside) transport. This pattern of inhibition of GLUT4 was also observed with cytochalasin B. The pattern of inhibition is consistent with interaction at the endofacial surface, but not the exofacial surface of the transporter. Occupation of the endofacial substrate site reduces maximum velocity under zero-trans conditions, because return of the substrate site to the outside is blocked, and no substrate is present inside to displace the inhibitor. Under equilibrium-exchange conditions, internal substrate competitively displaces the inhibitor, and the transport K-m is increased.

AB - The translocation of glucose transporter-4 (GLUT4) to the cell surface is a complex multistep process that involves movement of GLUT4 vesicles from a reservoir compartment, and docking and fusion of the vesicles with the plasma membrane. It has recently been proposed that a p38 mitogen-activated protein kinase ( MAPK)-dependent step may lead to intrinsic activation of the transporters exposed at the cell surface. In contrast to data obtained in muscle and adipocyte cell lines, we found that no insulin activation of p38 MAPK occurred in rat adipose cells. However, the p38 MAPK inhibitor SB203580 consistently inhibited transport activity after preincubation with the adipose cells. These apparently contradictory findings led us to hypothesize that the inhibitor may have a direct effect on the transport catalytic activity of GLUT4 that was independent of inhibition of the kinase. Kinetic analysis of 3-O-methyl-D-glucose transport activity revealed that SB203580 was a noncompetitive inhibitor of zero-trans ( substrate outside but not inside) transport, but was a competitive inhibitor of equilibrium-exchange ( substrate inside and outside) transport. This pattern of inhibition of GLUT4 was also observed with cytochalasin B. The pattern of inhibition is consistent with interaction at the endofacial surface, but not the exofacial surface of the transporter. Occupation of the endofacial substrate site reduces maximum velocity under zero-trans conditions, because return of the substrate site to the outside is blocked, and no substrate is present inside to displace the inhibitor. Under equilibrium-exchange conditions, internal substrate competitively displaces the inhibitor, and the transport K-m is increased.

U2 - 10.1210/en.2004-1294

DO - 10.1210/en.2004-1294

M3 - Article

VL - 146

SP - 1713

EP - 1717

JO - Endocrinology

JF - Endocrinology

SN - 0013-7227

IS - 4

ER -