Differential regulation of cardiac glucose and fatty acid uptake by endosomal pH and actin filaments.
Details
Serval ID
serval:BIB_6A3343A34E5D
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Differential regulation of cardiac glucose and fatty acid uptake by endosomal pH and actin filaments.
Journal
American Journal of Physiology. Cell Physiology
ISSN
1522-1563 (Electronic)
ISSN-L
0363-6143
Publication state
Published
Issued date
2010
Volume
298
Number
6
Pages
C1549-C1559
Language
english
Abstract
Insulin and contraction stimulate both cardiac glucose and long-chain fatty acid (LCFA) uptake via translocation of the substrate transporters GLUT4 and CD36, respectively, from intracellular compartments to the sarcolemma. Little is known about the role of vesicular trafficking elements in insulin- and contraction-stimulated glucose and LCFA uptake in the heart, especially whether certain trafficking elements are specifically involved in GLUT4 versus CD36 translocation. Therefore, we studied the role of coat proteins, actin- and microtubule-filaments and endosomal pH on glucose and LCFA uptake into primary cardiomyocytes under basal conditions and during stimulation with insulin or oligomycin (contraction-like AMP-activated protein kinase activator). Inhibition of coat protein targeting to Golgi/endosomes decreased insulin/oligomycin-stimulated glucose (-42%/-51%) and LCFA (-39%/-68%) uptake. Actin disruption decreased insulin/oligomycin-stimulated glucose uptake (-41%/-75%), while not affecting LCFA uptake. Microtubule disruption did not affect substrate uptake under any condition. Endosomal alkalinization increased basal sarcolemmal CD36 (2-fold), but not GLUT4, content, and concomitantly decreased basal intracellular membrane GLUT4 and CD36 content (-60% and -62%, respectively), indicating successful CD36 translocation and incomplete GLUT4 translocation. Additionally, endosomal alkalinization elevated basal LCFA uptake (1.4-fold) in a nonadditive manner to insulin/oligomycin, and decreased insulin/oligomycin-stimulated glucose uptake (-32%/-68%). In conclusion, 1) CD36 translocation, just like GLUT4 translocation, is a vesicle-mediated process depending on coat proteins, and 2) GLUT4 and CD36 trafficking are differentially dependent on endosomal pH and actin filaments. The latter conclusion suggests novel strategies to alter cardiac substrate preference as part of metabolic modulation therapy.
Keywords
AMP-Activated Protein Kinases/metabolism, Actin Cytoskeleton/drug effects, Actin Cytoskeleton/metabolism, Animals, Antigens, CD36/metabolism, Bicyclo Compounds, Heterocyclic/pharmacology, Biological Transport, Brefeldin A/pharmacology, Coatomer Protein/metabolism, Colchicine/pharmacology, Deoxyglucose/metabolism, Endosomes/drug effects, Endosomes/metabolism, Enzyme Activation, Enzyme Activators/pharmacology, Glucose Transporter Type 4/metabolism, Hydrogen-Ion Concentration, Insulin/metabolism, Male, Myocardial Contraction, Myocytes, Cardiac/drug effects, Myocytes, Cardiac/metabolism, Oligomycins/pharmacology, Palmitic Acid/metabolism, Protein Transport, Rats, Rats, Inbred Lew, Thiazolidines/pharmacology, Tubulin Modulators/pharmacology
Pubmed
Web of science
Create date
18/07/2013 10:19
Last modification date
20/08/2019 14:25