title: Mechano-chemical signaling maintains the rapid movement of Dictyostelium cells.
abstract: The survival of Dictyostelium cells depends on their ability to efficiently chemotax, either towards food or to form multicellular aggregates. Although the involvement of Ca2+ signaling during chemotaxis is well known, it is not clear how this regulates cell movement. Previously, fish epithelial keratocytes have been shown to display transient increases in intracellular calcium ([Ca2+]i) that are mediated by stretch-activated calcium channels (SACs), which play a role in retraction of the cell body [J. Lee, A. Ishihara, G. Oxford, B. Johnson, and K. Jacobson, Regulation of cell movement is mediated by stretch-activated calcium channels. Nature, 1999. 400(6742): p. 382-6.]. To investigate the involvement of SACs in Dictyostelium movement we performed high resolution calcium imaging in wild-type (NC4A2) Dictyostelium cells to detect changes in [Ca2+]i. We observed small, brief, Ca2+ transients in randomly moving wild-type cells that were dependent on both intracellular and extracellular sources of calcium. Treatment of cells with the SAC blocker gadolinium (Gd3+) inhibited transients and decreased cell speed, consistent with the involvement of SACs in regulating Dictyostelium motility. Additional support for SAC activity was given by the increase in frequency of Ca2+ transients when Dictyostelium cells were moving on a more adhesive substratum or when they were mechanically stretched. We conclude that mechano-chemical signaling via SACs plays a major role in maintaining the rapid movement of Dictyostelium cells.
authors: Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269, USA.
authors: M L
authors: ML
authors: Lombardi
authors: D A
authors: DA
authors: Knecht
authors: J
authors: J
authors: Lee
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D002448:Cell Adhesion; D002460:Cell Line; D002465:Cell Movement; D002633:Chemotaxis; D004023:Dictyostelium / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D040542:Mechanotransduction, Cellular
chemical_list: D002121:Calcium Channel Blockers; D002118:Calcium