The G protein beta subunit is essential for multiple responses to chemoattractants in Dictyostelium.

Wu, Lijun; Valkema, Romi; Haastert, Peter J.M. van; Devreotes, Peter N.

doi:10.1083/jcb.129.6.1667

Cited by 202 publications

(221 citation statements)

References 51 publications

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“…In fact, purified G proteins in phospholipid vesicles were activated in response to acute shear stress in the absence of other protein components (23). However, cells lacking β or γ subunits of G proteins migrate more slowly randomly, in chemotaxis, electrotaxis, and shear flow, and are deficient in phagocytosis, suggesting that the defect in mechanosensitivity might be related to the decreased baseline activity (13,(24)(25)(26).…”

Section: Discussionmentioning

confidence: 99%

Chemical and mechanical stimuli act on common signal transduction and cytoskeletal networks

Artemenko

Axiotakis

Borleis

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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Signal transduction pathways activated by chemoattractants have been extensively studied, but little is known about the events mediating responses to mechanical stimuli. We discovered that acute mechanical perturbation of cells triggered transient activation of all tested components of the chemotactic signal transduction network, as well as actin polymerization. Similarly to chemoattractants, the shear flow-induced signal transduction events displayed features of excitability, including the ability to mount a full response irrespective of the length of the stimulation and a refractory period that is shared with that generated by chemoattractants. Loss of G protein subunits, inhibition of multiple signal transduction events, or disruption of calcium signaling attenuated the response to acute mechanical stimulation. Unlike the response to chemoattractants, an intact actin cytoskeleton was essential for reacting to mechanical perturbation. These results taken together suggest that chemotactic and mechanical stimuli trigger activation of a common signal transduction network that integrates external cues to regulate cytoskeletal activity and drive cell migration.biochemical excitability | shear stress | motility | biomechanics | inflammation

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Section: Discussionmentioning

confidence: 99%

Chemical and mechanical stimuli act on common signal transduction and cytoskeletal networks

Artemenko

Axiotakis

Borleis

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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“…Strains carrying disruptions in the genes encoding ERK2 (1, 2, 16), cAMP receptors cAR1 and cAR3 (23), the G␤ subunit (24), and the G␣4 subunit (22,25) have been described previously. Wild-type and erk2 null cells expressing a His-tagged ERK2 were created by C. Gaskins and L. Aubry (Department of Biology, University of California, San Diego, La Jolla, CA).…”

Section: Methodsmentioning

confidence: 99%

Activation of the Mitogen-activated Protein Kinase ERK2 by the Chemoattractant Folic Acid in Dictyostelium

Maeda¹,

Firtel²

1997

Journal of Biological Chemistry

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In this study, we show that folic acid activates ERK2 in developmentally regulated manner and is required for ERK2 stimulation of adenylyl cyclase activity. Maximum levels of folate-stimulated ERK2 activity occur in cells from very early in development, prior to aggregation, and again at the tipped aggregate stages, corresponding to the stages in which folate receptors and the coupled G␣ subunit G␣4 are maximally expressed. During the activation by folic acid, ERK2 is phosphorylated on tyrosine residue(s) and contemporaneously shows a mobility shift on SDS-PAGE. Interestingly, this activation is not elicited in the absence of G␤ subunits, in contrast to the response to cAMP. This response also requires the G␣4 subunit known to be required for other folic acidmediated responses (Hadwiger, J., Lee, S., and Firtel, R. (1994) Proc. Natl. Acad. Sci. U. S. A. 91, 10566 -10570). Furthermore, we show that the activation of ERK2 by cAMP is independent of the G␣4 subunit, while the activation of ERK2 by folate is independent of G␣2. Taken together, these data indicate that there are at least two pathways of ERK2 activation, heterotrimeric G proteindependent and -independent pathways. MAP 1 kinase cascades are used by eukaryotes to couple extracellular signals to diverse intracellular regulatory pathways. The diversity of these pathways is great and includes growth factor responses in mammalian cells, cell-type differentiation in Drosophila and Caenorhabditis elegans, mating and growth responses in yeast, and stress-mediated responses in yeast and mammalian cells. These cascades are mediated by various classes of G protein-and tyrosine kinase-coupled receptors (5-13). In Dictyostelium, three presumably independent MAP kinase cascades play essential regulatory roles during both growth and multicellular development. The MAP kinase kinase (MEK) DdMEK1 is required for chemotaxis toward cAMP during aggregation; ddmek1 null cells form very small aggregates but continue to differentiate into normally proportioned, but very small, fruiting bodies (14). DdMEK1 is specifically required at the time of cAMP stimulation for the activation of guanylyl cyclase and the production of cGMP, the second messenger for chemotaxis in these cells. Two MAP kinases, ERK1 and ERK2, have been identified and their functions characterized. ERK1 is required for vegetative growth and is thought to play roles during multicellular development (15), while ERK2 is required for the activation of adenylyl cyclase by the chemoattractant cAMP during aggregation, prespore-specific gene expression, and morphogenesis (2, 16). erk2 null cells are aggregation-deficient due to the inability to activate adenylyl cyclase and relay the cAMP signal but show normal activation of guanylyl cyclase, which couples to chemotaxis (17). erk2 null cells expressing a temperature-sensitive ERK2 show abnormal morphogenesis during the multicellular stages, as well as the inability to induce prespore gene expression when shifted to a nonpermissive temperature. ERK2 activity is induce ϳ...

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“…Such analyses have allowed the evaluation and placement of potential effectors in the activation pathway of ACA. Although ACA can not be activated by cAMP in cells lacking either Gα2 or Gβ, gα2-nulls are fully responsive to GTPγS, whereas gβ-nulls are insensitive (Kumagai et al, 1991;Wu et al, 1995). Data suggest that while ACA activation requires CAR1/G protein signaling, this appears to be mediated via Gβγ, and not by Gα2.…”

Section: The Adenylyl Cyclases (Acs)mentioning

confidence: 91%

“…Dictyostelium has single genes for Gβ and Gγ, but 12 Gα genes (Wu et al, 1995;Zhang et al, 2001;Brzostowski et al, 2002). Gβ is absolutely essential for cAMP signaling, aggregation, and development.…”

Section: G Proteins Camp Affinity and Adaptationmentioning

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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The G protein beta subunit is essential for multiple responses to chemoattractants in Dictyostelium.

Abstract: Abstract. Increasing evidence suggests that the 13`/-subunit dimers of heterotrimeric G proteins play a pivotal role in transducing extracellular signals. The recent construction of G13 null mutants (gfl-) in Dictyostelium provides a unique opportunity to study the role of 13

Cited by 202 publications

References 51 publications

Chemical and mechanical stimuli act on common signal transduction and cytoskeletal networks

Chemical and mechanical stimuli act on common signal transduction and cytoskeletal networks

Activation of the Mitogen-activated Protein Kinase ERK2 by the Chemoattractant Folic Acid in Dictyostelium

Oscillatory signaling and network responses during the development of Dictyostelium discoideum

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