Sphingosine 1-phosphate induces cytoskeletal reorganization in C2C12 myoblasts: physiological relevance for stress fibres in the modulation of ion current through stretch-activated channels

Year: 2005

Authors: Formigli L., Meacci E., Sassoli C., Chellini F., Giannini R., Quercioli F., Tiribilli B., Squecco R., Bruni P., Francini Fa., Zecchi Orlandini S.

Autors Affiliation: Department of Anatomy, Histology, and Forensic Medicine, University of Florence, Italy;
Department of Physiological Sciences, Interuniversitary Institute of Miology (IIM), 85 50134 Florence, Italy;
Department of Biochemical Sciences, University of Florence, Italy;
Istituto Nazionale di Ottica Applicata, Largo E. Fermi 6, 50125 Firenze, Italy

Abstract: Sphingosine 1-phosphate (S1P) is a bioactive lipid that is abundantly present in the serum and mediates multiple biological responses. With the aim of extending our knowledge on the role played by S1P in the regulation of cytoskeletal reorganization, native as well as C2Cl2 myoblasts stably transfected with green fluorescent protein (GFP)-tagged alpha- and beta-actin constructs were stimulated with S1P (1 mu M) and observed under confocal and multiphoton microscopes. The addition of S1P induced the appearance of actin stress fibres and focal adhesions through Rho- and phospholipase D (PLD)-mediated pathways. The cytoskeletal response was dependent on the extracellular action of S1P through its specific surface receptors, since the intracellular delivery of the sphingolipid by microinjection was unable to modify the actin cytoskeletal assembly. Interestingly, it was revealed by whole-cell patch-clamp that S1P-induced stress fibre formation was associated with increased ion currents and conductance through stretch-activated channels (SACs), thereby suggesting a possible regulatory role for organized actin in channel sensitivity. Experiments aimed at stretching the plasma membrane of C2Cl2 cells, using the cantilever of an atomic force microscope, indicated that there was a Ca2+ influx through putative SACs. In conclusion, the present data suggest novel mechanisms of S1P signalling involving actin cytoskeletal reorganization and Ca2+ elevation through SACs that might influence myoblastic functions.

Journal/Review: JOURNAL OF CELL SCIENCE

Volume: 118 (6)      Pages from: 1161  to: 1171

KeyWords: alpha actin; beta actin; green fluorescent protein; phospholipase D; Rho factor; sphingosine 1 phosphate, actin polymerization; animal cell; article; atomic force microscopy; calcium transport; cell membrane; confocal microscopy; controlled study; cytoskeleton; focal adhesion; intracellular transport; ion conductance; ion current; microinjection; mouse; multiphoton microscopy; myoblast; nonhuman; patch clamp; priority journal; signal transduction; stress fiber; stretching; whole cell, Actins; Animals; Blotting, Western; Calcium; Cell Line; Cell Membrane; Cytoskeleton; Electrophysiology; Genetic Vectors; Green Fluorescent Proteins; Ion Transport; Ions; Lysophospholipids; Mice; Microscopy, Atomic Force; Microscopy, Confocal; Microscopy, Fluorescence; Myoblasts; Patch-Clamp Techniques; Phospholipase D; rho GTP-Binding Proteins; Signal Transduction; Sphingosine; Stress Fibers; Transfection, Animalia
DOI: 10.1242/jcs.01695

ImpactFactor: 6.543
Citations: 57
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