Regulation of G-proteins during chemotaxis in space and time

Kamp, Marjon E.

doi:10.33612/diss.102042787

Cited by 2 publications

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“…The scaffold LrrA coordinates in time and space the activation of multiple Gproteins (Gα, Gβγ, Ras, Rap, Rac) of cells in buffer and in chemotactic gradients, and thereby regulates many down-stream signaling pathways. lrrA-null cells in buffer have reduced Ras and increased Rap and Rac activation, and exhibit enhanced pseudopod activity [51]. Detailed pseudopod analysis confirms the complex phenotype of these cells, as nearly all aspects of pseudopod dynamics are altered in lrrA-null cells (Table 1): smaller size and shorter growth time due to enhanced STOP (b), enhanced START (α 1 ), and especially reduced inhibition of new pseudopods by extending pseudopods (A).…”

Section: Plos Onementioning

confidence: 70%

“…The leucine-rich-repeat protein LrrA is a scaffold connecting heterotrimeric and monomeric G-proteins in Dictyostelium [50,51]; the mammalian protein Shoc may have a similar function [52,53]. The scaffold LrrA coordinates in time and space the activation of multiple Gproteins (Gα, Gβγ, Ras, Rap, Rac) of cells in buffer and in chemotactic gradients, and thereby regulates many down-stream signaling pathways.…”

Section: Plos Onementioning

confidence: 99%

“…The cell lines used are the Dictyostelium wild-type AX3 and the mutants scar-null cells with a deletion of the scrA DDB_G0285253 gene [37], pla2-null with a deletion of the plaA DDB_G0278525 gene [38], gc-null with deletions of the gcA DDB_G0275009 gene encoding GCA and of the sgcA DDB_G0276269 gene encoding sGC [39], gbpC-null with a deletion of the gbpC DDB_G0291079 gene [41], myoII-null with a deletion of the mhcA DDB_G0286355 gene [119], forAEH-null with deletions of the forA DDB_G0279607 forE DDB_G0269626 gene and the forH DDB_G0285589 gene [47], racE-null cell with a deletion of the racE DDB_G0280975 gene [47], and the lrrA-null cells with a deletion of the lrrA DDB_G0294094 gene [50,51]. RapAG12V cells are AX3 wild-type that express the dominant active RapAG12V from an inducible promotor, and express the sensors Ral-GDS-GFP and cytosolic-RFP [120].…”

Section: Cell Lines and Preparationmentioning

confidence: 99%

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Unified control of amoeboid pseudopod extension in multiple organisms by branched F-actin in the front and parallel F-actin/myosin in the cortex

Haastert

2020

PLoS ONE

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The trajectory of moving eukaryotic cells depends on the kinetics and direction of extending pseudopods. The direction of pseudopods has been well studied to unravel mechanisms for chemotaxis, wound healing and inflammation. However, the kinetics of pseudopod extension–when and why do pseudopods start and stop- is equally important, but is largely unknown. Here the START and STOP of about 4000 pseudopods was determined in four different species, at four conditions and in nine mutants (fast amoeboids Dictyostelium and neutrophils, slow mesenchymal stem cells, and fungus B.d. chytrid with pseudopod and a flagellum). The START of a first pseudopod is a random event with a probability that is species-specific (23%/s for neutrophils). In all species and conditions, the START of a second pseudopod is strongly inhibited by the extending first pseudopod, which depends on parallel filamentous actin/myosin in the cell cortex. Pseudopods extend at a constant rate by polymerization of branched F-actin at the pseudopod tip, which requires the Scar complex. The STOP of pseudopod extension is induced by multiple inhibitory processes that evolve during pseudopod extension and mainly depend on the increasing size of the pseudopod. Surprisingly, no differences in pseudopod kinetics are detectable between polarized, unpolarized or chemotactic cells, and also not between different species except for small differences in numerical values. This suggests that the analysis has uncovered the fundament of cell movement with distinct roles for stimulatory branched F-actin in the protrusion and inhibitory parallel F-actin in the contractile cortex.

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Section: Plos Onementioning

confidence: 70%

Section: Plos Onementioning

confidence: 99%

Section: Cell Lines and Preparationmentioning

confidence: 99%

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Unified control of amoeboid pseudopod extension in multiple organisms by branched F-actin in the front and parallel F-actin/myosin in the cortex

Haastert

2020

PLoS ONE

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“…The activation of Ras and the formation of F-actin cannot be monitored in real time directly, but was measured by specific sensors: RBD-Raf-GFP for the active Ras-GTP (Kortholt et al, 2013) and LimE-GFP for both branched and parallel F-actin (Kamp, 2019). The results reveal that depletion of RBD-Raf-GFP occurs rapidly with an onset time of  = 1.15 ± 0.49s (Fig.…”

Section: Kinetics Of Sgc Activation and Translocation To The Cytoskeletonmentioning

confidence: 97%

Forty-five years of cGMP research in Dictyostelium: understanding the regulation and function of the cGMP pathway for cell movement and chemotaxis

Haastert

Keizer‐Gunnink

Pots

et al. 2021

MBoC

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In Dictyostelium chemoattractants induce a fast cGMP response that mediates myosin filament formation in the rear of the cell. The major cGMP signaling pathway consists of a soluble guanylyl cyclase sGC, a cGMP-stimulated cGMP-specific phosphodiesterase and the cGMP-target protein GbpC. Here we combine published experiments with many unpublished experiments performed in the past 45 years on the regulation and function of the cGMP signaling pathway. The chemoattractants stimulate heterotrimeric Gαβγ and monomeric Ras proteins. A fraction of the soluble guanylyl cyclase sGC binds with high affinity to a limited number of membrane binding site, which is essential for sGC to become activated by Ras and Gα proteins. sGC can also bind to F-actin; binding to branched F-actin in pseudopods enhances basal sGC activity, whereas binding to parallel F-actin in the cortex reduces sGC activity. The cGMP pathway mediates cell polarity by inhibiting the rear: in unstimulated cells by sGC activity in the branched F-actin of pseudopods, in a shallow gradient by stimulated cGMP formation in pseudopods at the leading edge, and during cAMP oscillation to erase the previous polarity and establish a new polarity axis that aligns with the direction of the passing cAMP wave.

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Regulation of G-proteins during chemotaxis in space and time

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Cited by 2 publications

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Unified control of amoeboid pseudopod extension in multiple organisms by branched F-actin in the front and parallel F-actin/myosin in the cortex

Unified control of amoeboid pseudopod extension in multiple organisms by branched F-actin in the front and parallel F-actin/myosin in the cortex

Forty-five years of cGMP research in Dictyostelium: understanding the regulation and function of the cGMP pathway for cell movement and chemotaxis

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