Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2011 Apr;52(4):699-711.
doi: 10.1194/jlr.M007138. Epub 2011 Feb 6.

Contraction-induced skeletal muscle FAT/CD36 trafficking and FA uptake is AMPK independent

J Jeppesen  1 , P H Albers, A J Rose, J B Birk, P Schjerling, N Dzamko, G R Steinberg, B Kiens
Affiliations

Contraction-induced skeletal muscle FAT/CD36 trafficking and FA uptake is AMPK independent

J Jeppesen et al. J Lipid Res. 2011 Apr.

Abstract

The aim of this study was to investigate the molecular mechanisms regulating FA translocase CD36 (FAT/CD36) translocation and FA uptake in skeletal muscle during contractions. In one model, wild-type (WT) and AMP-dependent protein kinase kinase dead (AMPK KD) mice were exercised or extensor digitorum longus (EDL) and soleus (SOL) muscles were contracted, ex vivo. In separate studies, FAT/CD36 translocation and FA uptake in response to muscle contractions were investigated in the perfused rat hindlimb. Exercise induced a similar increase in skeletal muscle cell surface membrane FAT/CD36 content in WT (+34%) and AMPK KD (+37%) mice. In contrast, 5-aminoimidazole-4-carboxamide ribonucleoside only induced an increase in cell surface FAT/CD36 content in WT (+29%) mice. Furthermore, in the perfused rat hindlimb, muscle contraction induced a rapid (1 min, +15%) and sustained (10 min, +24%) FAT/CD36 relocation to cell surface membranes. The increase in cell surface FAT/CD36 protein content with muscle contractions was associated with increased FA uptake, both in EDL and SOL muscle from WT and AMPK KD mice and in the perfused rat hindlimb. This suggests that AMPK is not essential in regulation of FAT/CD36 translocation and FA uptake in skeletal muscle during contractions. However, AMPK could be important in regulation of FAT/CD36 distribution in other physiological situations.

PubMed Disclaimer

Figures

Fig. 1.
Fig. 1.
Characterization of mouse skeletal muscle fractions. Mouse hindlimb muscles were excised and fractionated based upon a protocol of density-dependent separation. Protein concentrations of lysate (L), pellet 1 (P1), P2, and cytosol (C) were determined, equal protein amounts of these, as well as equal volume amounts of fractions 1–8 (F1–F8), were resolved by SDS-PAGE, and membranes were immunoblotted using antibodies specific for subcellular protein markers. These protein markers included transferrin receptor (TfR), glucose transporters 1 and 4 (GLUT1 and GLUT4, respectively), dihydroxypyridine receptor α-1 (DHPRα1), cytosolic fatty acid binding protein (FABPc), triadin/trisk95, and β-subunit of F1-ATPase (F1ATPase-β). Images of immunoblots are shown.
Fig. 2.
Fig. 2.
Skeletal muscle FAT/CD36 translocates from intracellular membranes to surface membranes during treadmill running exercise. Fed WT and AMPK KD mice were randomized into either a nonexercised basal group or an exercised group (n = 7–8). After 30 min at 17 m/min of treadmill running, mice were euthanized by cervical dislocation, and the hindlimb muscles were quickly removed and used for subcellular fractionation. Exercise induced a similar FAT/CD36 translocation to cell surface membranes from intracellular compartments in WT (A) and AMPK KD (B) mice. There was no difference in the redistribution pattern between WT and AMPK KD mice. The left panels show the average data of each fraction and the right panels show the delta difference in abundance between conditions in surface membrane (P1+P2) and intracellular membranes (F1–F8). Data are means ± SEM, * significant difference from basal, P < 0.05. Representative images of immunoblots are shown. For statistical evaluation, see Materials and Methods section.
Fig. 3.
Fig. 3.
AICAR induced skeletal muscle FAT/CD36 translocation from intracellular membranes to surface membranes in WT but not in AMPK KD mice. Fed WT and AMPK KD mice were given an intraperitoneal injection with a bolus of saline (600 μl/100 g body weight) with or without AICAR (25 mg/100 g body weight) (n = 8–9). After 60 min, mice were euthanized by cervical dislocation, and the hindlimb muscles were quickly removed and used for subcellular fractionation. AICAR induced a redistribution of FAT/CD36 to fractions enriched in heavy membranes away from low-density membranes in WT (A), but not in the AMPK KD mice (B). The left panels show the average data of each fraction and the right panels show the delta difference in abundance between conditions in surface membrane (P1+P2) and intracellular membranes (F1–F8). Data are means ± SEM, * significant difference from basal, P < 0.05. Representative images of immunoblots are shown. For statistical evaluation, see Materials and Methods section.
Fig. 4.
Fig. 4.
Effect of AICAR and exercise on AMPK activity and ACC-β Ser227 phosphorylation in skeletal muscle. AMPKα1 and -α2 activities (A, B) and ACC-β Ser227 phosphorylation (C, D) were determined in gastrocnemius muscles from WT and AMPK KD mice under resting conditions or following treadmill exercise (n = 7–8, A and C) or after saline or AICAR injection (n = 8–9, B and D). Data are means ± SEM, */*** significant difference from basal, P < 0.05/0.001, # significant difference between genotypes, P < 0.05. For statistical evaluation, see Materials and Methods section.
Fig. 5.
Fig. 5.
FA uptake in isolated EDL and SOL muscle during ex vivo muscle contraction. WT and AMPK KD mice were anesthetized with sodium pentobarbital (5 mg/100 g body weight), and the EDL and SOL muscles were carefully dissected tendon to tendon for muscle incubations. SOL (A) (n = 9–12) and EDL (B) (n = 9–12) muscles were incubated at rest or subjected to either AICAR (2 mM) or contractions (MC), EDL (50 Hz, 350 ms pulse duration, 6 tetani/min) and SOL (30 Hz, 600 ms pulse duration, 18 tetani/min) over 25 min. Data are means ± SEM, */*** significant difference from basal, P < 0.05/0.001.
Fig. 6.
Fig. 6.
Skeletal muscle FAT/CD36 translocates rapidly in the perfused rat hindlimb muscle during contractions. Rats were anesthetized by an intraperitoneal injection of pentobarbital sodium (4–5 mg/100 g body weight), and surgery for two-legged perfusion was performed. In one leg, isometric muscle contractions were induced in the gastrocnemius-plantaris muscle by stimulating the sciatic nerve electrically with supramaximal trains 5–15 V adjusted to obtain full fiber recruitment, 50 Hz with impulse duration of 1 ms, delivered every 3 s. Muscles were stimulated to contract for 1 or 10 min. There was a redistribution of FAT/CD36 to fractions enriched in heavy membranes away from low-density membranes after 1 min (A) (n = 6) and 10 min (B) (n = 6) of electrically induced muscle contraction compared with the resting contralateral control muscles. The left panels show the average data of each fraction and the right panels show the delta difference in abundance between conditions in surface membrane (P1+P2) and intracellular membranes (F1–F8). Data are means ± SEM, * significant difference from basal, P < 0.05. Representative images of immunoblots are shown. For statistical evaluation see Materials and Methods section.
Fig. 7.
Fig. 7.
Skeletal muscle signaling with contraction stimuli in the perfused rat hindlimb. Rats were anesthetized by an intraperitoneal injection of pentobarbital sodium (4–5 mg/100 g body weight), and surgery for two-legged perfusion was performed. Rats were subjected to sciatic nerve-induced contractions for either 1 (MC1) or 10 (MC10) min (n = 6) in situ, after which posterior hindlimb muscles (i.e., gastrocnemius and plantaris) from resting as well as stimulated conditions were excised. Phosphorylation of (A) calcium/calmodulin-dependent protein kinase II (CaMKIIThr287), (B) AMP-dependent protein kinase (AMPK) Thr172, (C) acetyl-CoA carboxylase (ACC) β Ser218, (D) extracellular-regulated protein kinase (ERK) TxY202/204, as well as AMPK α1 (E) and α2 activities (F) were determined in muscle lysates. Data are means ± SEM, */**/*** significant difference from basal, P < 0.05/0.01/0.001. Representative images of immunoblots are shown. MC, muscle contractions. For statistical evaluation, see Materials and Methods section.
Fig. 8.
Fig. 8.
FA uptake and oxidation during muscle contraction in the perfused rat hindlimb. Rats were anesthetized by an intraperitoneal injection of pentobarbital sodium (4–5 mg/100 g body weight), and surgery for two-legged perfusion was performed. Rats were subjected to sciatic nerve-induced contractions for either 1 min (MC 1) or 10 min (MC 10) (n = 8), in situ. FA uptake and oxidation were measured as arterial – venous differences in [14C] and [14CO2], respectively. Skeletal muscle FA uptake was increased after 1 min and 10 min of muscle contractions, (A), whereas FA oxidation was similar between rest and 1 min of muscle contractions, but increased 73% after 10 min of muscle contractions (B). Data are means ± SEM, */*** significant difference from basal, P < 0.05/0.001. For statistical evaluation, see Materials and Methods section.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Roepstorff C., Steffensen C. H., Madsen M., Stallknecht B., Kanstrup I. L., Richter E. A., Kiens B. 2002. Gender differences in substrate utilization during submaximal exercise in endurance-trained subjects. Am. J. Physiol. Endocrinol. Metab. 282: E435–E447. - PubMed
    1. Stellingwerff T., Boon H., Jonkers R. A., Senden J. M., Spriet L. L., Koopman R., van Loon L. J. 2007. Significant intramyocellular lipid use during prolonged cycling in endurance-trained males as assessed by three different methodologies. Am. J. Physiol. Endocrinol. Metab. 292: E1715–E1723. - PubMed
    1. Romijn J. A., Coyle E. F., Sidossis L. S., Gastaldelli A., Horowitz J. F., Endert E., Wolfe R. R. 1993. Regulation of endogenous fat and carbohydrate metabolism in relation to exercise intensity and duration. Am. J. Physiol. 265: E380–E391. - PubMed
    1. Burguera B., Proctor D., Dietz N., Guo Z., Joyner M., Jensen M. D. 2000. Leg free fatty acid kinetics during exercise in men and women. Am. J. Physiol. Endocrinol. Metab. 278: E113–E117. - PubMed
    1. Kiens B. 2006. Skeletal muscle lipid metabolism in exercise and insulin resistance. Physiol. Rev. 86: 205–243. - PubMed

Publication types

MeSH terms

LinkOut - more resources