Isolation of two genes encoding putative protein kinases regulated during Dictyostelium discoideum development

Bürki, E.; Anjard, Christophe; Scholder, Jean-Charles; Reymond, Christophe

doi:10.1016/0378-1119(91)90538-m

Cited by 51 publications

(25 citation statements)

References 35 publications

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“…There was also no evidence of a membrane-spanning sequence, suggesting that PTP3 is a soluble protein. PTP3 has a significant number of homopolymer runs of Asn, Ser, Thr, and Gln, a feature which is not uncommon for D. discoideum coding sequences (6,32,37,49). Very striking is the run of 50 Asn (AAT) residues between the two NsiI sites ( Fig.…”

Section: Resultsmentioning

confidence: 97%

Multiple Roles of the Novel Protein Tyrosine Phosphatase PTP3 during Dictyostelium Growth and Development

Gamper

Howard

Hunter

et al. 1996

Molecular and Cellular Biology

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PTP3, the third nonreceptor protein tyrosine phosphatase identified in Dictyostelium discoideum, has a single catalytic protein tyrosine phosphatase domain. Recombinant PTP3 exhibited phosphatase activity that was inhibited by vanadate. PTP3 is expressed at a moderate level during growth. The level of transcripts increased between growth and 8 h of development and declined thereafter. Expression of lacZ under the control of the PTP3 promoter indicated a spatial localization of PTP3 in the anterior-like and prestalk cell types. There are two copies of the PTP3 gene in this haploid organism. Disruption of one copy led to a slow-growth phenotype. We were unable to obtain a strain with disruptions in both PTP3 genes. Overexpression of wild-type PTP3 led to slower growth rates and the formation of large aggregation streams. These streams split into smaller aggregates, many of which then arrested in development. Overexpression of a catalytically inactive mutation (Cys to Ser) had no effect on growth rate; however, this strain also formed large aggregation streams that later split up into large and small mound structures and became fruiting bodies of various sizes. Antiphosphotyrosine Western blot (immunoblot) analysis of total cell proteins showed that the pattern of protein tyrosine phosphorylation was specifically altered in PTP3 mutants. Addition of growth medium to starving cells and a subsequent replacement with nonnutrient buffer led to reciprocal changes in the pattern of several phosphotyrosine proteins, including a protein of ϳ130 kDa. Analysis of strains overexpressing active or inactive PTP3 suggested that p130 is a potential substrate of PTP3. A transient posttranslational phosphorylation of PTP3 further supported the role of PTP3 in these processes. The data obtained strongly suggest new regulatory functions for PTP3 that are distinct from those described earlier for D. discoideum PTP1 and PTP2.

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Section: Resultsmentioning

confidence: 97%

Multiple Roles of the Novel Protein Tyrosine Phosphatase PTP3 during Dictyostelium Growth and Development

Gamper

Howard

Hunter

et al. 1996

Molecular and Cellular Biology

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“…The cloned PKA-C gene translates into a protein of 73 kDa, which is not sensitive to proteolytic cleavage [27]. Furthermore the cloned gene is equally expressed during the entire course of development [3,28], whereas expression of the 40 kDa protein increased sharply after aggregation [29]. The purified C-subunit showed rather unusual sensitivity to regulation by pH [26]; it would be of interest to determine whether the cloned PKA-C shows the same biochemical properties and if not, to intensify the search for a second PKA-C gene.…”

Section: Resultsmentioning

confidence: 99%

cAMP‐dependent protein kinase activity is essential for preaggregative gene expression in Dictyostelium

Schulkes

Schaap

1995

FEBS Letters

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“…(The accession number for RIP3 is AF159241.) Although RIP3 has a higher fraction of such sequences than most Dictyostelium genes, such regions have been observed in numerous Dictyostelium genes and most are not thought to play a role in the function of the protein (Burki et al, 1991;Mann and Firtel, 1991;Pitt et al, 1992). A BLAST search did not suggest that RIP3 is highly homologous to known proteins.…”

Section: Identification Of Rip3mentioning

confidence: 92%

A Novel Ras-interacting Protein Required for Chemotaxis and Cyclic Adenosine Monophosphate Signal Relay inDictyostelium

Lee

Parent

Insall

et al. 1999

MBoC

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We have identified a novel Ras-interacting protein from Dictyostelium, RIP3, whose function is required for both chemotaxis and the synthesis and relay of the cyclic AMP (cAMP) chemoattractant signal. rip3 null cells are unable to aggregate and lack receptor activation of adenylyl cyclase but are able, in response to cAMP, to induce aggregation-stage, postaggregative, and cell-type-specific gene expression in suspension culture. In addition, rip3 null cells are unable to properly polarize in a cAMP gradient and chemotaxis is highly impaired. We demonstrate that cAMP stimulation of guanylyl cyclase, which is required for chemotaxis, is reduced ϳ60% in rip3 null cells. This reduced activation of guanylyl cyclase may account, in part, for the defect in chemotaxis. When cells are pulsed with cAMP for 5 h to mimic the endogenous cAMP oscillations that occur in wild-type strains, the cells will form aggregates, most of which, however, arrest at the mound stage. Unlike the response seen in wild-type strains, the rip3 null cell aggregates that form under these experimental conditions are very small, which is probably due to the rip3 null cell chemotaxis defect. Many of the phenotypes of the rip3 null cell, including the inability to activate adenylyl cyclase in response to cAMP and defects in chemotaxis, are very similar to those of strains carrying a disruption of the gene encoding the putative Ras exchange factor AleA. We demonstrate that aleA null cells also exhibit a defect in cAMP-mediated activation of guanylyl cyclase similar to that of rip3 null cells. A double-knockout mutant (rip3/aleA null cells) exhibits a further reduction in receptor activation of guanylyl cyclase, and these cells display almost no cell polarization or movement in cAMP gradients. As RIP3 preferentially interacts with an activated form of the Dictyostelium Ras protein RasG, which itself is important for cell movement, we propose that RIP3 and AleA are components of a Ras-regulated pathway involved in integrating chemotaxis and signal relay pathways that are essential for aggregation.

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Isolation of two genes encoding putative protein kinases regulated during Dictyostelium discoideum development

Cited by 51 publications

References 35 publications

Multiple Roles of the Novel Protein Tyrosine Phosphatase PTP3 during Dictyostelium Growth and Development

Multiple Roles of the Novel Protein Tyrosine Phosphatase PTP3 during Dictyostelium Growth and Development

cAMP‐dependent protein kinase activity is essential for preaggregative gene expression in Dictyostelium

A Novel Ras-interacting Protein Required for Chemotaxis and Cyclic Adenosine Monophosphate Signal Relay inDictyostelium

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