Structurally distinct and stage-specific adenylyl cyclase genes play different roles in dictyostelium development

Pitt, Geoffrey S.; Milona, Nina; Borleis, Jane; Lin, Kenneth; Reed, Randall R.; Devreotes, Peter N.

doi:10.1016/0092-8674(92)90411-5

Cited by 298 publications

(293 citation statements)

References 40 publications

Supporting

Mentioning

286

Contrasting

Order By: Relevance

“…Together, they are responsible for about one-third of the chemotactic response as indicated by the chemotaxis index of gc-null cells of 0.43 compared with 0.64 of gc-null cells expressing the wild-type sGC protein, or wild-type AX3 cells. The chemotaxis index of gc-null cells is similar to the chemotaxis defects observed in PI3K-null cells (Funamoto et al, 2001;Loovers et al, 2006) but much larger than the minimal defects seen in PLC-null (Drayer et al, 1994) and adenylyl cyclase-null cells (Pitt et al, 1992;Stepanovic et al, 2005). In Dictyostelium, cGMP is involved in the regulation of myosin.…”

Section: Discussionsupporting

confidence: 56%

Guanylyl Cyclase Protein and cGMP Product Independently Control Front and Back of ChemotaxingDictyosteliumCells

Veltman

Haastert

2006

MBoC

View full text Add to dashboard Cite

Chemotaxis of amoeboid cells is driven by actin filaments in leading pseudopodia and actin-myosin filaments in the back and at the side of the cell to suppress pseudopodia. In Dictyostelium, cGMP plays an important role during chemotaxis and is produced predominantly by a soluble guanylyl cyclase (sGC). The sGC protein is enriched in extending pseudopodia at the leading edge of the cell during chemotaxis. We show here that the sGC protein and the cGMP product have different functions during chemotaxis, using two mutants that lose either catalytic activity (sGC⌬cat) or localization to the leading edge (sGC⌬N). Cells expressing sGC⌬N exhibit excellent cGMP formation and myosin localization in the back of the cell, but they exhibit poor orientation at the leading edge. Cells expressing the catalytically dead sGC⌬cat mutant show poor myosin localization at the back, but excellent localization of the sGC protein at the leading edge, where it enhances the probability that a new pseudopod is made in proximity to previous pseudopodia, resulting in a decrease of the degree of turning. Thus cGMP suppresses pseudopod formation in the back of the cell, whereas the sGC protein refines pseudopod formation at the leading edge. INTRODUCTIONChemotaxis is a vital process in a variety of organisms, ranging from bacteria to vertebrates. Prokaryotes use chemotaxis to move toward high nutrient concentrations or away from unfavorable conditions, whereas in eukaryotes chemotaxis is also involved in embryogenesis, wound healing, and the immune response. Chemotaxis is achieved by coupling gradient sensing to basic cell movement. Prokaryotes are too small to sense spatial gradients and therefore rely on temporal changes of the chemoattractant concentration to achieve chemotaxis. They do this by adjusting their tumbling frequency in response to temporal changes of the chemoattractant concentration (Szurmant and Ordal, 2004;Wadhams and Armitage, 2004). Eukaryotic cells are typically large enough to be able to measure a spatial gradient. The difference in receptor occupation between each side of the cell leads to an internal polarization. A pseudopod is extended at the side with the highest receptor occupation and at the same time, pseudopod formation at all other sides is repressed, resulting in directional cell migration (Devreotes and Janetopoulos, 2003;Postma et al., 2004).Dictyostelium is a eukaryotic organism that is widely used to study chemotaxis (Williams and Harwood, 2003;Parent, 2004;Affolter and Weijer, 2005). Starved Dictyostelium cells periodically secrete cAMP. Through relay of the cAMP signal by neighboring cells, concentric cAMP waves are generated. Starved Dictyostelium cells are chemotactically sensitive to cAMP and by movement in the direction of the origin of the cAMP waves, the cells are able to aggregate into groups of up to 100,000 cells. The chemotactic response of Dictyostelium is optimized for the dynamic cAMP waves that coordinate both aggregation and multicellular development. Cells show a much stronger chemotact...

show abstract

Section: Discussionsupporting

confidence: 56%

Guanylyl Cyclase Protein and cGMP Product Independently Control Front and Back of ChemotaxingDictyosteliumCells

Veltman

Haastert

2006

MBoC

View full text Add to dashboard Cite

show abstract

“…The region between the two hydrophobic segments shows no homology to the corresponding region of the adenylate cyclase of A. cylindrica or CyaA of S. platensisis. The adenylate cyclases of eukaryotes such as Dictyostelium discoideum (ACG) (38), Trypanosoma brucei (GRESAG4s and ESAG 4) (2), and Leishmania donovani (RAC-A and RAC-B) (40) have domain organizations similar to that of CyaA. It has been pointed out that the structures of these adenylate cyclases are similar to that of the transmembrane receptor protein (38).…”

Section: Resultsmentioning

confidence: 99%

Isolation and characterization of multiple adenylate cyclase genes from the cyanobacterium Anabaena sp. strain PCC 7120

Katayama

Ohmori

1997

J Bacteriol

View full text Add to dashboard Cite

Adenylate cyclase genes, designated cyaA, cyaB1, cyaB2, cyaC, and cyaD, were isolated from the filamentous cyanobacterium Anabaena sp. strain PCC 7120 by complementation of a strain of Escherichia coli defective for the presence of cya. These genes encoded polypeptides consisting of 735, 859, 860, 1,155, and 546 amino acid residues, respectively. Deduced amino acid sequences of the regions near the C-terminal ends of these cya genes were similar to those of catalytic domains of eukaryotic adenylate cyclases. The remaining part of each cya gene towards its N-terminal end showed a characteristic structure. CyaA had two putative membrane-spanning regions. Both CyaB1 and CyaB2 had regions that were very similar to the cyclic GMP (cGMP)-binding domain of cGMP-stimulated cGMP phosphodiesterase. CyaC consisted of four distinct domains forming sequentially from the N terminus: a response regulator-like domain, a histidine kinase-like domain, a response regulatorlike domain, and the catalytic domain of adenylate cyclase. CyaD contained the forkhead-associated domain in its N-terminal region. Expression of these genes was examined by reverse transcription-PCR. The transcript of cyaC was shown to be predominant in this cyanobacterium. The cellular cyclic AMP level in the disruptant of the cyaC mutant was much lower than that in the wild type.Cyclic AMP (cAMP) regulates various biological activities in both prokaryotes and eukaryotes. In prokaryotes, cAMP and cAMP receptor protein regulate gene expression (7). In eukaryotes, cAMP regulates enzyme activity (11), channel activity (42), and gene expression (34) via the cAMP-dependent protein kinase. In cyanobacteria, it has been reported that cellular cAMP content is affected by growth conditions (17,22), that cAMP concentration changes rapidly in response to light-off and light-on signals (37) or to a pH shift (36), and that cAMP interferes with the pattern formation of heterocysts (43). However, it is still unknown whether cAMP functions as an intracellular signal molecule in cyanobacteria.Recently, we isolated adenylate cyclase (cya) genes from the filamentous cyanobacteria Anabaena cylindrica (26) and Spirulina platensis (52). Regions near the C-terminal ends of the adenylate cyclases of both cyanobacteria showed significant structural similarity to the catalytic domain of the adenylate cyclase of eukaryotes but showed no homology to that of prokaryotes such as Escherichia coli. Furthermore, cyanobacterial adenylate cyclases appeared to be membrane oriented.To study the physiological functions of these adenylate cyclases, disruption or overexpression of cya genes is indispensable. Unfortunately, both A. cylindrica and S. platensis are not transformable, so they are not suitable for this purpose. In this study, we isolated cya genes from a transformable cyanobacterium, Anabaena sp. strain PCC 7120, and constructed mutants defective in cya genes. Some physiological properties of these mutants were determined. MATERIALS AND METHODSStrains and growth conditions. Anabaena sp. s...

show abstract

“…10. When cAMP binds to cAMP surface receptor 1 (cAR1), it activates both the adenyl cyclase A (ACA) and the mitogenactivated protein kinase ERK2 (15,20). ACA catalyzes cAMP FIG.…”

Section: Discussionmentioning

confidence: 99%

Constitutively Active Protein Kinase A Disrupts Motility and Chemotaxis inDictyostelium discoideum

et al. 2003

View full text Add to dashboard Cite

The deletion of the gene for the regulatory subunit of protein kinase A (PKA) results in constitutively active PKA in the pkaR mutant. To investigate the role of PKA in the basic motile behavior and chemotaxis of Dictyostelium discoideum, pkaR mutant cells were subjected to computer-assisted two-and three-dimensional motion analysis. pkaR mutant cells crawled at only half the speed of wild-type cells in buffer, chemotaxed in spatial gradients of cyclic AMP (cAMP) but with reduced efficiency, were incapable of suppressing lateral pseudopods in the front of temporal waves of cAMP, a requirement for natural chemotaxis, did not exhibit the normal velocity surge in response to the front of a wave, and were incapable of chemotaxing toward an aggregation center in natural waves generated by wild-type cells that made up the majority of cells in mixed cultures. Many of the behavioral defects appeared to be the result of the constitutively ovoid shape of the pkaR mutant cells, which forced the dominant pseudopod off the substratum and to the top of the cell body. The behavioral abnormalities that pkaR mutant cells shared with regA mutant cells are discussed by considering the pathway ERK2 OԽ RegA OԽ [cAMP] 3 PKA, which emanates from the front of a wave. The results demonstrate that cells must suppress PKA activity in order to elongate along a substratum, suppress lateralpseudopod formation, and crawl and chemotax efficiently. The results also implicate PKA activation in dismantling cell polarity at the peak and in the back of a natural cAMP wave.As a population of Dictyostelium amoebae aggregate to a center, each amoeba must respond to the different phases of relayed, outwardly moving, nondissipating symmetric waves of the chemoattractant cyclic AMP (cAMP) (Fig. 1). In the front of each wave, cells experience a positive spatial gradient of cAMP (i.e., the concentration increases in the direction of the aggregation center) and an increasing temporal gradient of cAMP (i.e., the concentration increases with time). At the peak of each wave, cells experience a cAMP concentration that causes cellular depolarization, and in the back of each wave, cells experience a negative spatial gradient of cAMP (i.e., the concentration decreases in the direction of the aggregation center) and a decreasing temporal gradient of cAMP (i.e., the concentration decreases with time) (Fig. 1). Amoebae respond to each phase of a natural wave in a distinct and reproducible fashion, resulting in a sequence of behaviors that together represent the natural chemotactic response (29,32,37,40,41,47,48). In the absence of any external chemotactic signal, Dictyostelium amoebae translocate at near-maximum velocity and turn frequently (47,48). We propose that this basic motile behavior is modulated in the different phases of the natural wave, with the net result of directing cells into the aggregation center (29) (Fig. 1). During aggregation, cells are exposed to a series of waves with an average periodicity of 7 min (1). With each wave, translocation toward th...

show abstract

Structurally distinct and stage-specific adenylyl cyclase genes play different roles in dictyostelium development

Cited by 298 publications

References 40 publications

Guanylyl Cyclase Protein and cGMP Product Independently Control Front and Back of ChemotaxingDictyosteliumCells

Guanylyl Cyclase Protein and cGMP Product Independently Control Front and Back of ChemotaxingDictyosteliumCells

Isolation and characterization of multiple adenylate cyclase genes from the cyanobacterium Anabaena sp. strain PCC 7120

Constitutively Active Protein Kinase A Disrupts Motility and Chemotaxis inDictyostelium discoideum

Contact Info

Product

Resources

About