title: Reversible stress-induced lipid body formation in fast twitch rat myofibers.
abstract: We analyzed the existence of lipid bodies (LBs) in the fast twitch rat flexor digitorum brevis (FDB) myofibers and found that these structures were scarce. However, isolation procedure of the myofibers, heath shock, viral infection or the glycosylation inhibitor tunicamycin induced formation of the LBs, which were stationary structures flanking Z lines. We next infected FDB myofibers with recombinant Semliki Forest virus expressing caveolin 3-yellow fluorescent protein (cav3-YFP) since this chimeric protein was targeted to the LBs facilitating their further analysis. Photobleaching experiments showed that the LBs recovered cav 3-YFP extremely slowly, indicating that they were not continuous with the endoplasmic/sarcoplasmic reticulum. We found, however, that cav3-YFP could move from the LBs to the sarcolemma and this phenomenon was sensitive to Brefeldin A, suggesting that the chimeric protein could be returned from the LBs to the endoplasmic reticulum.
authors: Department of Anatomy and Cell Biology, Institute of Biomedicine, P.O. Box 5000, Aapistie 7, FI 90014 University of Oulu, Finland.
authors: Mika
authors: M
authors: Nevalainen
authors: Mika
authors: M
authors: Kaakinen
authors: Paavo
authors: P
authors: Rahkila
authors: Kalervo
authors: K
authors: Metsikkö
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D015153:Blotting, Western; D051244:Caveolin 3 / Q000378:metabolism; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D059865:Endoplasmic Reticulum Stress; D005260:Female; D006056:Golgi Apparatus / Q000378:metabolism; D050356:Lipid Metabolism / Q000502:physiology*; D050155:Lipogenesis / Q000502:physiology; D008164:Luminescent Proteins / Q000378:metabolism; D018656:Muscle Fibers, Fast-Twitch / Q000166:cytology / Q000378:metabolism*; D021381:Protein Transport; D051381:Rats; D017207:Rats, Sprague-Dawley; D012508:Sarcolemma / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D014780:Viruses / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D051244:Caveolin 3; D008164:Luminescent Proteins; C054562:yellow fluorescent protein, Bacteria; D002784:Cholesterol