G alpha 3 regulates the cAMP signaling system in Dictyostelium.

Brandon, Maureen; Podgorski, Gregory J.

doi:10.1091/mbc.8.9.1677

Cited by 18 publications

(16 citation statements)

References 34 publications

(46 reference statements)

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“…Gα2 mediates cAMP‐induced activation of guanylyl cyclase and phospholipase C (Okaichi et al ., 1992; Bominaar and Van Haastert, 1994) and by release of Gβγ of adenylyl cyclase (Wu et al ., 1995a). Gα3 null mutants show an as yet uncharacterized defect in cAMP signal production (Brandon and Podgorski, 1997). Gα4 mediates activation of guanylyl cyclase and, via Gβγ, of adenylyl cyclase by folate, a chemoattractant secreted by bacteria (Hadwiger et al ., 1994).…”

Section: Introductionmentioning

confidence: 99%

Temperature-sensitive Gbeta mutants discriminate between G protein-dependent and -independent signaling mediated by serpentine receptors

et al. 1998

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Deletion of the single gene for the Dictyostelium G protein β-subunit blocks development at an early stage. We have now isolated temperature-sensitive alleles of Gβ to investigate its role in later development. We show that Gβ is directly required for adenylyl cyclase A activation and for morphogenetic signaling during the entire developmental program. Gβ was also essential for induction of aggregative gene expression by cAMP pulses, a process that is mediated by serpentine cAMP receptors (cARs). However, Gβ was not required for cAR-mediated induction of prespore genes and repression of stalk genes, and neither was Gβ needed for induction of prestalk genes by the differentiation inducing factor (DIF). cAMP induction of prespore genes and repression of stalk genes is mediated by the protein kinase GSK-3. GSK-3 also determines cell-type specification in insects and vertebrates and is regulated by the wingless/wnt morphogens that are detected by serpentine fz receptors. The G protein-dependent and -independent modes of cAR-mediated signaling reported here may also exist for the wingless/wnt signaling pathways in higher organisms.

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Section: Introductionmentioning

confidence: 99%

Temperature-sensitive Gbeta mutants discriminate between G protein-dependent and -independent signaling mediated by serpentine receptors

et al. 1998

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“…The developmental arrest of amiB À cells possibly resulted in inef®cient synergetic development with wild-type cells. These features distinguish the amiB À mutant from other early developmental mutants such as those of RasG, one member of Ras family proteins, Ga3, a G-protein alpha subunit, and DdMyb2, all of which are essential for early development (Khosla et al 1996;Brandon & Podgorski 1997;Otsuka & Van Haastert 1998). Wild-type cells expressing constitutively active RasG (G12T) as well as ga3 À and Ddmyb2 À cells, fail to express normal levels of cAR1 or ACA and display the aggregate-less phenotype.…”

Section: Discussionmentioning

confidence: 99%

amiB, a novel gene required for the growth/differentiation transition in Dictyostelium

2000

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Background: The differentiation programme of Dictyostelium discoideum is initiated by starvation. Nutrient depletion triggers the differentiation of Dictyostelium cells through the transcriptional inactivation of some growth-phase genes, as well as through the transcriptional activation of essential genes required for the aggregation of the cells. The adenylyl cyclase (ACA) gene, acaA, is one of the earliest genes expressed following starvation. ACA produces intracellular and extracellular cAMP that drives further differentiation by inducing chemotaxis, developmental gene expression and morphogenesis of Dictyostelium cells. Although several genes have been identi®ed as being essential for the initiation of differentiation process, such as the transcriptional activation of ACA expression, the molecular mechanisms of the growth/differentiation transition remain to be explored.

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“…The strains used in this study are shown in Table 1. Cells were grown in liquid culture and starved as described previously in Brandon & Podgorski (1997). HL5 medium for HPS400 and JH10 was supplemented with 100 µg/mL thymidine.…”

Section: Methodsmentioning

confidence: 99%

“…We have previously reported that a strain of cells containing a targeted disruption of the Dictyostelium Gα3 gene ( gα3 – cells) are blocked in aggregation and the expressions of several early development genes are aberrant (Brandon & Podgorski 1997; Brandon et al . 1997).…”

Section: Introductionmentioning

confidence: 99%

Gα3 and protein kinase A represent cross‐talking pathways for gene expression in Dictyostelium discoideum

2002

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Heterotrimeric G proteins and protein kinase A (PKA) are regulators of development in Dictyostelium discoideum . It has been reported that disruption of the Dictyostelium G ␣ 3 gene ( g ␣ 3 -) blocks development and expression of several early development genes, characteristics that are reminiscent of mutants lacking the catalytic subunit of PKA ( pkac -). The hypothesis that G ␣ 3 and PKA signaling pathways may interact to control developmental gene expression was tested by comparing the regulation of seven genes expressed early in development in the wild-type and in g ␣ 3 -and pkac -mutants, and comparing PKA activity in the wild-type and in a g ␣ 3 -mutant. The expression patterns of six genes were affected similarly by the G ␣ 3 and PKA mutations, while the expression of only one gene, the cAMP receptor 1 ( cAR1 ), differed between the mutants. PKA activity, measured by phosphorylation of the PKA-specific substrate Kemptide, was higher in g ␣ 3 -cells than in wildtype cells, suggesting that G ␣ 3 normally exerts an inhibitory effect on PKA activity. Although some early development genes appear to require both G ␣ 3 and PKA for expression, the differing response of cAR1 expression and the inhibitory effect of G ␣ 3 on PKA activity suggest that G ␣ 3 and PKA are members of interacting pathways controlling gene expression early in development.

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G alpha 3 regulates the cAMP signaling system in Dictyostelium.

Cited by 18 publications

References 34 publications

Temperature-sensitive Gbeta mutants discriminate between G protein-dependent and -independent signaling mediated by serpentine receptors

Temperature-sensitive Gbeta mutants discriminate between G protein-dependent and -independent signaling mediated by serpentine receptors

amiB, a novel gene required for the growth/differentiation transition in Dictyostelium

Gα3 and protein kinase A represent cross‐talking pathways for gene expression in Dictyostelium discoideum

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