FAT/CD36 is localized in sarcolemma and in vesicle-like structures in subsarcolemma regions but not in mitochondria

• Published in: Journal of lipid research 2010-06, Vol.51 (6), p.1504-1512
• Main Authors: Jeppesen, Jacob, Mogensen, Martin, Prats, Clara, Sahlin, Kent, Madsen, Klavs, Kiens, Bente
• Format: Article
• Language: English
• Subjects: Adult; Animals; CD36 Antigens - metabolism; Cell Respiration; Female; Fysiologi; Fysiologi och farmakologi; Gene Expression Regulation; human; Humans; Immunoblotting; immunocytochemistry; Immunohistochemistry; Intracellular Space - metabolism; isolated mitochondria; Male; MEDICIN; Medicin och hälsovetenskap; Medicin/Teknik; MEDICINE; Medicine/Technology; Mitochondria - metabolism; Muscle, Skeletal - cytology; Muscle, Skeletal - metabolism; Physiology; Physiology and pharmacology; Protein Transport; Rats; Sarcolemma - metabolism; skeletal muscle; Young Adult; Zucker rats
• ISSN: 0022-2275; 1539-7262; 1539-7262
• DOI: 10.1194/jlr.M003756

The primary aim of the present study was to investigate in which cellular compartments fatty acid trans­locase CD36 (FAT/CD36) is localized. Intact and fully functional skeletal muscle mitochondria were isolated from lean and obese female Zucker rats and from 10 healthy male individuals. FAT/CD36 could not be detected in the isolated mitochondria, whereas the mitochondrial marker F1ATPase-β was clearly detected using immunoblotting. Lack of markers for other membrane structures indicated that the mitochondria were not contaminated with membranes known to contain FAT/CD36. In addition, fluorescence immunocytochemistry was performed on single muscle fibers dissected from soleus muscle of lean and obese Zucker rats and from the vastus lateralis muscle from humans. Costaining against FAT/CD36 and MitoNEET clearly show that FAT/CD36 is highly present in sarcolemma and it also associates with some vesicle-like intracellular compartments. However, FAT/CD36 protein was not detected in mitochondrial membranes, supporting the biochemical findings. Based on the presented data, FAT/CD36 seems to be abundantly expressed in sarcolemma and in vesicle-like structures throughout the muscle cell. However, FAT/CD36 is not present in mitochondria in rat or human skeletal muscle. Thus, the functional role of FAT/CD36 in lipid transport seems primarily to be allocated to the plasma membrane in skeletal muscle.