Adipocytes exhibit abnormal subcellular distribution and translocation of vesicles containing glucose transporter 4 and insulin-regulated aminopeptidase in type 2 diabetes mellitus: Implications regarding defects in vesicle trafficking

被引:79
作者
Maianu, L
Keller, SR
Garvey, WT
机构
[1] Med Univ S Carolina, Div Endocrinol Diabet & Med Genet, Dept Med, Charleston, SC 29425 USA
[2] Ralph H Johnson Vet Affairs Med Ctr, Charleston, SC 29425 USA
[3] Univ Virginia, Sch Med, Dept Med, Charlottesville, VA 22908 USA
关键词
D O I
10.1210/jc.86.11.5450
中图分类号
R5 [内科学];
学科分类号
1002 ; 100201 ;
摘要
Insulin resistance in type 2 diabetes is due to impaired stimulation of the glucose transport system in muscle and fat. Different defects are operative in these two target tissues because glucose transporter 4 (GLUT 4) expression is normal in muscle but markedly reduced in fat. In muscle, GLUT 4 is redistributed to a dense membrane compartment, and insulin-mediated translocation to plasma membrane (PM) is impaired. Whether similar trafficking defects are operative in human fat is unknown. Therefore, we studied subcellular localization of GLUT4 and insulin-regulated aminopeptidase (IRAP; also referred to as vp165 or gp160), which is a constituent of GLUT4 vesicles and also translocates to PM in response to insulin. Subcutaneous fat was obtained from eight normoglycemic control subjects (body mass index, 29 +/- 2 kg/m(2)) and eight type 2 diabetic patients (body mass index, 30 +/- 1 kg/m(2); fasting glucose, 14 +/- 1 mm). In adipocytes isolated from diabetics, the basal 3-O-methylglucose transport rate was decreased by 50% compared with controls (7.1 +/- 2.9 vs. 14.1 +/- 3.7 mmol/mm(2) surface area/min), and there was no increase in response to maximal insulin (7.9 +/- 2.7 vs. 44.5 +/- 9.2 in controls). In membrane subfractions from controls, insulin led to a marked increase of IRAP in the PM from 0.103 +/- 0.04 to 1.00 +/- 0.33 relative units/mg protein, concomitant with an 18% decrease in low-density microsomes and no change in high-density microsomes (HDM). In type 2 diabetes, IRAP overall expression in adipocytes was similar to that in controls; however, two abnormalities were observed. First, in basal cells, IRAP was redistributed away from low-density microsomes, and more IRAP was recovered in HDM (1.2-fold) and PM (4.4-fold) from diabetics compared with controls. Second, IRAP recruitment to PM by maximal insulin was markedly impaired. GLUT4 was depleted in all membrane subfractions (43-67%) in diabetes, and there was no increase in PM GLUT4 in response to insulin. Type 2 diabetes did not affect the fractionation of marker enzymes. We conclude that in human adipocytes: 1) IRAP is expressed and translocates to PM in response to insulin; 2) GLUT4 depletion involves all membrane subfractions in type 2 diabetes, although cellular levels of IRAP are normal; and 3) in type 2 diabetes, IRAP accumulates in membrane vesicles cofractionating with HDM and PM under basal conditions, and insulin-mediated recruitment to PM is impaired. Therefore, in type 2 diabetes, adipocytes express defects in trafficking of GLUT4/IRAP-containing vesicles similar to those causing insulin resistance in skeletal muscle.
引用
收藏
页码:5450 / 5456
页数:7
相关论文
共 43 条
[1]   Identification and characterization of two distinct intracellular GLUT4 pools in rat skeletal muscle: evidence for an endosomal and an insulin-sensitive GLUT4 compartment [J].
Aledo, JC ;
Lavoie, L ;
Volchuk, A ;
Keller, SR ;
Klip, A ;
Hundal, HS .
BIOCHEMICAL JOURNAL, 1997, 325 :727-732
[2]   PREPARATION AND PROPERTIES OF PLASMA MEMBRANE AND ENDOPLASMIC RETICULUM FRAGMENTS FROM ISOLATED RAT FAT CELLS [J].
AVRUCH, J ;
WALLACH, DFH .
BIOCHIMICA ET BIOPHYSICA ACTA, 1971, 233 (02) :334-&
[3]   Glucosamine induces insulin resistance in vivo by affecting GLUT 4 translocation in skeletal muscle - Implications for glucose toxicity [J].
Baron, AD ;
Zhu, JS ;
Weldon, H ;
Maianu, L ;
Garvey, WT .
JOURNAL OF CLINICAL INVESTIGATION, 1995, 96 (06) :2792-2801
[4]  
BRADFORD MM, 1976, ANAL BIOCHEM, V72, P248, DOI 10.1016/0003-2697(76)90527-3
[5]   Insulin-stimulated translocation of GLUT4 glucose transporters requires SNARE-complex proteins [J].
Cheatham, B ;
Volchuk, A ;
Kahn, CR ;
Wang, L ;
Rhodes, CJ ;
Klip, A .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1996, 93 (26) :15169-15173
[6]   ROLE OF GLUCOSE-TRANSPORT IN THE POSTRECEPTOR DEFECT OF NON-INSULIN-DEPENDENT DIABETES-MELLITUS [J].
CIARALDI, TP ;
KOLTERMAN, OG ;
SCARLETT, JA ;
KAO, M ;
OLEFSKY, JM .
DIABETES, 1982, 31 (11) :1016-1022
[7]   BIOGENESIS OF ENDOPLASMIC RETICULUM MEMBRANES .2. SYNTHESIS OF CONSTITUTIVE MICROSOMAL ENZYMES IN DEVELOPING RAT HEPATOCYTE [J].
DALLNER, G ;
SIEKEVITZ, P ;
PALADE, GE .
JOURNAL OF CELL BIOLOGY, 1966, 30 (01) :97-+
[8]   AN INVITRO HUMAN MUSCLE PREPARATION SUITABLE FOR METABOLIC STUDIES - DECREASED INSULIN STIMULATION OF GLUCOSE-TRANSPORT IN MUSCLE FROM MORBIDLY OBESE AND DIABETIC SUBJECTS [J].
DOHM, GL ;
TAPSCOTT, EB ;
PORIES, WJ ;
DABBS, DJ ;
FLICKINGER, EG ;
MEELHEIM, D ;
FUSHIKI, T ;
ATKINSON, SM ;
ELTON, CW ;
CARO, JF .
JOURNAL OF CLINICAL INVESTIGATION, 1988, 82 (02) :486-494
[9]   Possible role for gp160 in constitutive but not insulin-stimulated GLUT4 trafficking: dissociation of gp160 and GLUT4 localization [J].
Filippis, A ;
Clark, S ;
Proietto, J .
BIOCHEMICAL JOURNAL, 1998, 330 :405-411
[10]  
Fleischer B, 1974, Methods Enzymol, V31, P180