Cyclic Amp Signals and the Control of Cell Aggregation in Dictyostelium Discoideum

Gerisch, G.; Maeda, Yasuo; Malchow, Dieter; Roos, Werner; Wick, U.; Wurster, Bernd

doi:10.1016/b978-0-444-41608-7.50017-4

Cited by 56 publications

(61 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The activation by cAMP could be mediated by an intracellular effector such as cyclic GMP [22] acting on a protein kinase [23], or calcium [24], though this ion seems to affect the basal activity of adenylate cyclase rather than the oscillations [5]. To represent the regulation by cAMP, we made the simplest assumption that the receptor behaves as a regulatory subunit of adenylate cyclase; we further assumed that the catalytic and regulatory entities are dimers, and that the resulting complex obeys the concerted allosteric model [25] with exclusive binding of substrate and positive effector to the R state.…”

Section: Resultsmentioning

confidence: 99%

Excitability in the adenylate cyclase reaction in Dictyostelium discoideum

Goldbeter

Erneux

1978

FEBS Letters

View full text Add to dashboard Cite

Section: Resultsmentioning

confidence: 99%

Excitability in the adenylate cyclase reaction in Dictyostelium discoideum

Goldbeter

Erneux

1978

FEBS Letters

View full text Add to dashboard Cite

“…Adaptation drives attraction and accumulation in randomly swimming bacteria (19,72). In leukocytes and myxamoebae, contraction accompanies the application of a stimulant gradient or a pulse (3,30,73), but does not recur as either cell type advances up the succeeding spatial gradient. Thus, only temporal gradients may induce adaptation responses (see also references 50 and 61) and, perhaps, directed pseudopods (9,31).…”

Section: Effects Of Stimulant Impulsesmentioning

confidence: 99%

Chemoattraction and chemotaxis in Dictyostelium discoideum: myxamoeba cannot read spatial gradients of cyclic adenosine monophosphate.

Vicker¹,

Schill²,

Drescher³

1984

The Journal of Cell Biology

View full text Add to dashboard Cite

Myxamoebae of the morphogenetic cellular slime mold Dictyostelium discoideum are thought to be able to accurately read and respond to directional information in spatial gradients of cyclic AMP. We examined the spatial and temporal mechanisms proposed for chemotaxis by comparing the behavior of spreading or evenly distributed cell populations after exposure to well-defined spatial gradients . The effects of gradient generation on cells were avoided by using predeveloped gradients . Qualitatively different responses were obtained using (a) isotropic, (b) static spatial, or (c) temporal (impulse) gradients in a simple chamber of penetrable micropore filters . We simulated models of chemotaxis and chemokinesis to aid our interpretations . The attractive and locomotory responses of populations were maximally stimulated by 0.05 AM cyclic AMP, provided that cellular phosphodiesterase was inhibited . But a single impulse of cyclic AMP during gradient development caused a greater and qualitatively different attraction . Attraction in spatial gradients was only transient, in that populations eventually developed a random distribution when confined to a narrow territory . Populations never accumulated nor lost their random distribution even in extremely steep spatial gradients . Attraction in spatial gradients was inducible only in spreading populations, not randomly distributed ones. Thus, spatial gradients effect biased-random locomotion : i.e ., chemokinesis without adaptation . Cells cannot read gradients; the reaction of the cells is stochastic. Spatial gradients do not cause chemotaxis, which probably requires a sharp stimulant concentration increase (a temporal gradient) as a pulse or impulse . The results also bear on concepts of how embryonic cells might be able to decipher the positional information in a morphogen spatial gradient during development .The morphogenesis of free-living myxamoebae of Dictyostelium discoideum into a differentiated metazoan is characterized by the intermingling effects of cyclic AMP (cAMP), including increased cohesiveness, chemokinesis, chemotaxis, cell polarization, CAMP and cAMP phosphodiesterase (PDE)' synthesis and emission, aggregation, and differentiation (1-8). The aggregation of dispersed populations follows starvation and depends partly on the reception and excretion of cAMP by each cell. Emissions first appear in a pulsatile form and cause the orientation of individual cells (3, 9), but they later coalesce into streams, which efficiently guide them to-'Abbreviations used in this paper: BBSS, Bonner's buffered salt solution ; DTT, dithiothreitol; PDE, phosphodiestease; SM medium, Sussman's standard medium ; 0, diameter .ward the aggregation center. Such morphogenic fields (10) might be indispensable determinants of cell positioning, patterning, and organismal form during embryogenesis (11,12) . However, the mechanisms of directed locomotion and their relation to the effect of morphogens on cells remain largely unclear.The possible mechanisms of chemotaxis are prevale...

show abstract

“…Certain cells first secrete cAMP in a pulsatile manner, inducing surrounding cells to migrate toward the original source of cAMP (17). The affected cells secrete cAMP in response to the original pulse, resulting in signal amplification and relay and giving rise to periodic outward propagating waves of cAMP that direct cell movement toward the origin (4)(5)(6)(17)(18)(19)(20). Another role for cAMP early in development has been revealed by observations that either pulses or high continuous levels of exogenous cAMP induce prematurely the appearance of several developmentally regulated proteins (21)(22)(23)(24)(25)(26)(27)(28).…”

mentioning

confidence: 99%

“…Growing cells exist as unicellular amoebae in the presence of a complete nutrient medium. When amoebae are starved and plated at an air-liquid interface, a well-defined developmental program ensues in which cells secrete 3',5'-cyclic AMP (cAMP) (3) in a pulsatile manner (4)(5)(6), stream toward aggregation centers, and form multicellular aggregates that differentiate into stalk and spore tissues (1,2). Some genes are expressed only during discrete stages of this developmental cycle: if cells are labeled with 15-to 30-min pulses of [a5S]methionine at various intervals throughout the 24-hr developmental program, and the protein products are separated on O'Farrell two-dimensional gels (7), about 100 of the 400 observable spots change substantially in relative intensity at some period of development (8).…”

mentioning

confidence: 99%

A role for cyclic AMP in expression of developmentally regulated genes in Dictyostelium discoideum.

Landfear¹,

Lodish²

1980

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

View full text Add to dashboard Cite

Starved cells of Dictyostelium discoideum begin to synthesize a new class of developmentally regulated proteins at about 13 hr of the 24-hr developmental program, concomitant with the formation of tips on the tight cell aggregates [Alton, Dev. Biol. 60, 180-2061. Continued synthesis of these proteins is normally dependent upon the integrity of the multicellular aggregates, because cells that have been disaggregated at 13 hr and shaken in suspension for 5 hr do not make these proteins. We show here that addition of 20 AM cyclic AMP to suspension cultures of disaggregated 13-hr cells caused synthesis of most of these late proteins to be maintained. Translation in an in vitro wheat germ system of total cellular RNA isolated from these cyclic AMP-stimulated suspension cells, or from normal aggregates, generated several proteins that were not encoded by the RNA isolated from equivalent suspension cells which had not been treated with cyclic AMP or from preaggregation cells. We conclude that cyclic AMP has a direct role in maintaining the synthesis of aggregation-dependent Dictyostelium proteins and in maintaining the level of the corresponding mRNAs.The cellular slime mold Dictyostelium discoideum presents an ideal eukaryotic system in which to study the control of developmentally regulated genes (1, 2). Growing cells exist as unicellular amoebae in the presence of a complete nutrient medium. When amoebae are starved and plated at an air-liquid interface, a well-defined developmental program ensues in which cells secrete 3',5'-cyclic AMP (cAMP) (3) in a pulsatile manner (4-6), stream toward aggregation centers, and form multicellular aggregates that differentiate into stalk and spore tissues (1, 2). Some genes are expressed only during discrete stages of this developmental cycle: if cells are labeled with 15-to 30-min pulses of [a5S]methionine at various intervals throughout the 24-hr developmental program, and the protein products are separated on O'Farrell two-dimensional gels (7), about 100 of the 400 observable spots change substantially in relative intensity at some period of development (8). The most pronounced alteration occurs around 10-13 hr in the developmental cycle, at the time when tight cell-cell aggregates have formed and tips begin to appear at the top of the mounds: approximately 40 proteins that were made at low levels or not at all in 3-hr cells are induced to high levels of synthesis. The continued pronounced synthesis of these developmentally controlled proteins is dependent upon the maintainance of cell contact, because mounds that are disaggregated selectively arrest or attentuate the synthesis of these late species (9). In this paper, we present evidence that cAMP is directly involved in controlling the expression of this class of genes.The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "ad- Autoradiograms were made by exposing a gel containing 106 cpm of trichloroacetic acid-precipitable -5S for 24 hr; ...

show abstract

Cyclic Amp Signals and the Control of Cell Aggregation in Dictyostelium Discoideum

Cited by 56 publications

References 20 publications

Excitability in the adenylate cyclase reaction in Dictyostelium discoideum

Excitability in the adenylate cyclase reaction in Dictyostelium discoideum

Chemoattraction and chemotaxis in Dictyostelium discoideum: myxamoeba cannot read spatial gradients of cyclic adenosine monophosphate.

A role for cyclic AMP in expression of developmentally regulated genes in Dictyostelium discoideum.

Contact Info

Product

Resources

About