title: Intracellular photoactivation of caged cGMP induces myosin II and actin responses in motile cells.
abstract: Cyclic GMP (cGMP) is a ubiquitous second messenger in eukaryotic cells. It is assumed to regulate the association of myosin II with the cytoskeleton of motile cells. When cells of the social amoeba Dictyostelium discoideum are exposed to chemoattractants or to increased osmotic stress, intracellular cGMP levels rise, preceding the accumulation of myosin II in the cell cortex. To directly investigate the impact of intracellular cGMP on cytoskeletal dynamics in a living cell, we released cGMP inside the cell by laser-induced photo-cleavage of a caged precursor. With this approach, we could directly show in a live cell experiment that an increase in intracellular cGMP indeed induces myosin II to accumulate in the cortex. Unexpectedly, we observed for the first time that also the amount of filamentous actin in the cell cortex increases upon a rise in the cGMP concentration, independently of cAMP receptor activation and signaling. We discuss our results in the light of recent work on the cGMP signaling pathway and suggest possible links between cGMP signaling and the actin system.
authors.affiliation: Biological Physics, Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Str. 24/25, 14476 Potsdam, Germany. beta@uni-potsdam.de.
authors.forename: Eva K B
authors.initials: EK
authors.lastname: Pfannes
authors.forename: Alexander
authors.initials: A
authors.lastname: Anielski
authors.forename: Matthias
authors.initials: M
authors.lastname: Gerhardt
authors.forename: Carsten
authors.initials: C
authors.lastname: Beta
mesh_terms: D000199:Actins / Q000502:physiology*; D002460:Cell Line; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000494:pharmacology; D003599:Cytoskeleton / Q000502:physiology*; D004023:Dictyostelium / Q000166:cytology / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D008856:Microscopy, Fluorescence; D024462:Myosin Type II / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology
chemical_list: D000199:Actins; C099978:4,5-dimethoxy-2-nitrobenzyl-8-bromo-cGMP; D024462:Myosin Type II; D006152:Cyclic GMP