Lysophosphatidic Acid- and Gβ-Dependent Activation of Dictyostelium MAP Kinase ERK2

Schenk, Paul W.; Epskamp, S. J. P.; Knetsch, Menno L. W.; Harten, V.; Lagendijk, Ellen; Duijn, Bert van; Snaar-Jagalska, B. E.

doi:10.1006/bbrc.2001.4649

Cited by 12 publications

(5 citation statements)

References 48 publications

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“…In contrast, LPA-induced chemotaxis was completely prevented by the PTX pretreatment (Fig. 2C), consistent with previous reports (Gerrard et al, 1980;Schenk et al, 2001;Maghazachi, 2003;Stahle et al, 2003).…”

Section: Resultssupporting

confidence: 93%

β-Arrestin 2-Dependent Angiotensin II Type 1A Receptor-Mediated Pathway of Chemotaxis

Hunton

Barnes²,

Kim³

et al. 2005

Mol Pharmacol

113

126

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Section: Resultssupporting

confidence: 93%

β-Arrestin 2-Dependent Angiotensin II Type 1A Receptor-Mediated Pathway of Chemotaxis

Hunton

Barnes²,

Kim³

et al. 2005

Mol Pharmacol

113

126

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“…Cell motility alteration and chemoattraction occurring through inverse agonist effects on constitutive GPCR signaling has been previously reported in cultured vertebrate cells [31], [32]. LPA is known to be an attractant for many cells that are prokaryotic predators [59], [60]. Therefore, LPA could represent a reasonable nutrient chemoattraction signal for Tetrahymena .…”

Section: Discussionmentioning

confidence: 86%

“…Based on the domain similarity with the fungal nutrient receptors, one hypothesis would be that Gpcr6p is directly responsible for detection of carbohydrates, amino acids, lysolipids, or other nutrients [19], [20], [58], [59]. The nutrient GPCRs in yeast may detect a variety of nutrients, with low affinities for each, allowing for broad range nutrient detection [19].…”

Section: Discussionmentioning

confidence: 99%

A Knockout Mutation of a Constitutive GPCR in Tetrahymena Decreases Both G-Protein Activity and Chemoattraction

2011

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Although G-protein coupled receptors (GPCRs) are a common element in many chemosensory transduction pathways in eukaryotic cells, no GPCR or regulated G-protein activity has yet been shown in any ciliate. To study the possible role for a GPCR in the chemoresponses of the ciliate Tetrahymena, we have generated a number of macronuclear gene knockouts of putative GPCRs found in the Tetrahymena Genome database. One of these knockout mutants, called G6, is a complete knockout of a gene that we call GPCR6 (TTHERM_00925490). Based on sequence comparisons, the Gpcr6p protein belongs to the Rhodopsin Family of GPCRs. Notably, Gpcr6p shares highest amino acid sequence homologies to GPCRs from Paramecium and several plants. One of the phenotypes of the G6 mutant is a decreased responsiveness to the depolarizing ions Ba2+ and K+, suggesting a decrease in basal excitability (decrease in Ca2+ channel activity). The other major phenotype of G6 is a loss of chemoattraction to lysophosphatidic acid (LPA) and proteose peptone (PP), two known chemoattractants in Tetrahymena. Using microsomal [35S]GTPγS binding assays, we found that wild-type (CU427) have a prominent basal G-protein activity. This activity is decreased to the same level by pertussis toxin (a G-protein inhibitor), addition of chemoattractants, or the G6 mutant. Since the basal G-protein activity is decreased by the GPCR6 knockout, it is likely that this gene codes for a constitutively active GPCR in Tetrahymena. We propose that chemoattractants like LPA and PP cause attraction in Tetrahymena by decreasing the basal G-protein stimulating activity of Gpcr6p. This leads to decreased excitability in wild-type and longer runs of smooth forward swimming (less interrupted by direction changes) towards the attractant. Therefore, these attractants may work as inverse agonists through the constitutively active Gpcr6p coupled to a pertussis-sensitive G-protein.

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“…The MAPK Erk2 is also required for ACA activation and is activated by chemoattractant, but the mechanism is unknown (Schenk et al 2001, Segall et al 1995. Furthermore, Erk2 also inhibits RegA, a cAMP phosphodiesterase (Pde2, discussed below).…”

Section: Components Involved In Aca Activationmentioning

confidence: 99%

CHEMOATTRACTANT SIGNALING IN DICTYOSTELIUM DISCOIDEUM

Manahan

Iglesias²,

Lan

et al. 2004

Annu. Rev. Cell Dev. Biol.

171

153

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Dictyostelium is an accessible organism for studies of signaling via chemoattractant receptors. Chemoattractant-mediated signaling events and components are reviewed and presented as a series of connected modules, including excitation, inhibition, G protein-independent responses, early gene expression, inositol lipids, PH domain-containing proteins, cyclic AMP signaling, polarization acquisition, actin polymerization, and cortical myosin. The network incorporates information from biochemical, genetic, and cell biological experiments carried out on living cells. The modules and connections represent current understanding, and future information is expected to modify and build upon this structure.

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Lysophosphatidic Acid- and Gβ-Dependent Activation of Dictyostelium MAP Kinase ERK2

Cited by 12 publications

References 48 publications

β-Arrestin 2-Dependent Angiotensin II Type 1A Receptor-Mediated Pathway of Chemotaxis

β-Arrestin 2-Dependent Angiotensin II Type 1A Receptor-Mediated Pathway of Chemotaxis

A Knockout Mutation of a Constitutive GPCR in Tetrahymena Decreases Both G-Protein Activity and Chemoattraction

CHEMOATTRACTANT SIGNALING IN DICTYOSTELIUM DISCOIDEUM

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