A novel cGMP signalling pathway mediating myosin phosphorylation and chemotaxis in Dictyostelium

Bosgraaf, Leonard; Russcher, Henk; Smith, Janet L.; Wessels, Deborah; Soll, David R.; Haastert, Peter J.M. van

doi:10.1093/emboj/cdf438

Cited by 132 publications

(182 citation statements)

References 39 publications

(46 reference statements)

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“…Similar defects were observed in a knockout mutant lacking the cGMP binding protein GbpC, strongly indicating that a cGMP-mediated pathway via activation of GbpC controls cortical localization and function of myosin II in chemotactic cells. 12 Our uncaging experiments clearly confirm these earlier results. They provide a direct proof that an increase in the cytosolic cGMP concentration triggers myosin II translocation to the cortex.…”

Section: Discussionsupporting

confidence: 90%

“…18,19 Furthermore, the two large multi-domain proteins GbpC and GpcD have been characterized. 12 It was found that GbpD acts independently of intracellular cyclic nucleotides. It promotes surface attachment via lateral pseudopods and depolarization as part of a GbpD/Rap/PI3K pathway.…”

Section: Introductionmentioning

confidence: 99%

“…Activation of GbpC by cGMP is essential for myosin II regulation during chemotaxis, multicellular streaming, and resistance to osmotic stress. 12,22 Subsequent studies revealed a rich topology of domains that led to the classification of GbpC as a member of the Roco family of proteins. 23 A multi-step intramolecular activation mechanism has been identified for this protein 24,25 and its subcellular localization in response to cAMP-stimuli and osmotic shock was studied.…”

Section: Introductionmentioning

confidence: 99%

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Intracellular photoactivation of caged cGMP induces myosin II and actin responses in motile cells

et al. 2013

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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. Insight, innovation, integrationSecond messengers like cGMP play a central role in the regulatory pathways of living cells. Here, we demonstrate that an increase in intracellular cGMP can trigger not only myosin II but also actin responses in motile amoeboid cells. In previous studies, an increase in intracellular cGMP was induced indirectly via membrane receptor stimulation. In the present work, we employ, for the first time, the direct light-induced release of cGMP from a caged precursor to raise the cytosolic cGMP level in Dictyostelium cells that carry fluorescent markers for filamentous actin and myosin II. Based on this advanced combination of live cell photo-uncaging and multi-color confocal microscopy, we could identify a link between cGMP and actin dynamics in motile amoeboid cells.

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Section: Discussionsupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intracellular photoactivation of caged cGMP induces myosin II and actin responses in motile cells

et al. 2013

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“…In vitro assays have shown that the cAMP-stimulated incorporation of myosin filaments into the Triton-insoluble cytoskeleton is absent in gc-null cells (Liu et al, 1993;Bosgraaf et al, 2002). To investigate the effects of the sGC protein and the cGMP product on myosin incorporation into the cytoskeleton, we coexpressed myosin-GFP in the various mutant sGC cell strains.…”

Section: Effects Of Sgc and Cgmp On Myosin Distributionmentioning

confidence: 99%

Guanylyl Cyclase Protein and cGMP Product Independently Control Front and Back of ChemotaxingDictyosteliumCells

Veltman

Haastert

2006

MBoC

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Chemotaxis of amoeboid cells is driven by actin filaments in leading pseudopodia and actin-myosin filaments in the back and at the side of the cell to suppress pseudopodia. In Dictyostelium, cGMP plays an important role during chemotaxis and is produced predominantly by a soluble guanylyl cyclase (sGC). The sGC protein is enriched in extending pseudopodia at the leading edge of the cell during chemotaxis. We show here that the sGC protein and the cGMP product have different functions during chemotaxis, using two mutants that lose either catalytic activity (sGC⌬cat) or localization to the leading edge (sGC⌬N). Cells expressing sGC⌬N exhibit excellent cGMP formation and myosin localization in the back of the cell, but they exhibit poor orientation at the leading edge. Cells expressing the catalytically dead sGC⌬cat mutant show poor myosin localization at the back, but excellent localization of the sGC protein at the leading edge, where it enhances the probability that a new pseudopod is made in proximity to previous pseudopodia, resulting in a decrease of the degree of turning. Thus cGMP suppresses pseudopod formation in the back of the cell, whereas the sGC protein refines pseudopod formation at the leading edge. INTRODUCTIONChemotaxis is a vital process in a variety of organisms, ranging from bacteria to vertebrates. Prokaryotes use chemotaxis to move toward high nutrient concentrations or away from unfavorable conditions, whereas in eukaryotes chemotaxis is also involved in embryogenesis, wound healing, and the immune response. Chemotaxis is achieved by coupling gradient sensing to basic cell movement. Prokaryotes are too small to sense spatial gradients and therefore rely on temporal changes of the chemoattractant concentration to achieve chemotaxis. They do this by adjusting their tumbling frequency in response to temporal changes of the chemoattractant concentration (Szurmant and Ordal, 2004;Wadhams and Armitage, 2004). Eukaryotic cells are typically large enough to be able to measure a spatial gradient. The difference in receptor occupation between each side of the cell leads to an internal polarization. A pseudopod is extended at the side with the highest receptor occupation and at the same time, pseudopod formation at all other sides is repressed, resulting in directional cell migration (Devreotes and Janetopoulos, 2003;Postma et al., 2004).Dictyostelium is a eukaryotic organism that is widely used to study chemotaxis (Williams and Harwood, 2003;Parent, 2004;Affolter and Weijer, 2005). Starved Dictyostelium cells periodically secrete cAMP. Through relay of the cAMP signal by neighboring cells, concentric cAMP waves are generated. Starved Dictyostelium cells are chemotactically sensitive to cAMP and by movement in the direction of the origin of the cAMP waves, the cells are able to aggregate into groups of up to 100,000 cells. The chemotactic response of Dictyostelium is optimized for the dynamic cAMP waves that coordinate both aggregation and multicellular development. Cells show a much stronger chemotact...

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“…During chemotaxis, pseudopod formation is generally restricted to the leading edge of the cell, as myosin filaments that localize to the rear inhibit pseudopod extension (Figure 3). Cells that are defective in cGMP production or that lack the cGMP binding protein GbpC are defective in myosin assembly and are unable to suppress lateral pseudopod extension (Bosgraaf et al, 2002;Veltman and van Haastert, 2006;. Although these cells have many protrusions that arise spontaneously around the cell periphery, they are still capable of effective directional chemotaxis, as these lateral pseudopods are less persistent than those at the leading edge.…”

Section: Cgmp-signalingmentioning

confidence: 99%

Oscillatory signaling and network responses during the development of Dictyostelium discoideum

McMains

Liao

Kimmel

2008

Ageing Research Reviews

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Periodic biological variations reflect interactions among molecules and cells, or even organisms. The Dictyostelium cAMP oscillatory circuit is a highly robust example. cAMP oscillations in Dictyostelium arise intracellularly by a complex interplay of activating and inhibiting pathways, are transmitted extracellularly, and synchronize an entire local population. Once established, cAMP signal-relay persists stably for hours. On a two-dimensional surface, >100,000 cells may form a single coordinated territory. In suspension culture, >10 10 cells can oscillate in harmony. This review focuses on molecular mechanisms that cyclically activate and attenuate signal propagation and on chemotactic responses to oscillatory wave progression.

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A novel cGMP signalling pathway mediating myosin phosphorylation and chemotaxis in Dictyostelium

Cited by 132 publications

References 39 publications

Intracellular photoactivation of caged cGMP induces myosin II and actin responses in motile cells

Intracellular photoactivation of caged cGMP induces myosin II and actin responses in motile cells

Guanylyl Cyclase Protein and cGMP Product Independently Control Front and Back of ChemotaxingDictyosteliumCells

Oscillatory signaling and network responses during the development of Dictyostelium discoideum

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