scholarly journals Interaction between the chemotactic cAMP receptor and a detergent-insoluble membrane residue of Dictyostelium discoideum. Modulation by guanine nucleotides.

1988 ◽  
Vol 263 (17) ◽  
pp. 8326-8331
Author(s):  
M E Ludérus ◽  
R van Driel
Keyword(s):  
Dictyostelium Discoideum ◽  
Guanine Nucleotides ◽  
Camp Receptor

scholarly journals cAMP induces a rapid and reversible modification of the chemotactic receptor in Dictyostelium discoideum.

1985 ◽  
Vol 100 (3) ◽  
pp. 715-720 ◽  
Author(s):  
C Klein ◽  
J Lubs-Haukeness ◽  
S Simons
Keyword(s):  
Dictyostelium Discoideum ◽  
Concentration Dependence ◽  
Time Course ◽  
Camp Synthesis ◽  
Sds Page ◽  
Reversible Modification ◽  
Camp Receptor ◽  
Camp Stimulation ◽  
Stimulation Of

Stimulation, within 1 min after cAMP stimulation, of aggregation-competent Dictyostelium discoideum amebae was found to cause a rapid (within 1 min) modification of the cell's surface cAMP receptor. The modified receptor migrated on SDS PAGE as a 47,000-mol-wt protein, as opposed to a 45,000-mol-wt protein labeled on unstimulated cells. The length of time this modified receptor could be detected depended upon the strength of the cAMP stimulus: 3-4 min after treatment with 10(-7) M cAMP, cells no longer possessed the 47,000-mol-wt form of the cAMP receptor. Instead, the 45,000-mol-wt form was present. Stimulation of cells with 10(-5) M cAMP, however, resulted in the persistent (over 15 min) expression of the modified receptor. The time course, concentration dependence, and specificity of stimulus for this cAMP-induced shift in the cAMP receptor were found to parallel the cAMP-stimulated phosphorylation of a 47,000-mol-wt protein. In addition, both phenomena were shown to occur in the absence of endogenous cAMP synthesis. The possibility that the cAMP receptor is phosphorylated in response to cAMP stimulation, and the role of this event in cell desensitization, are discussed.

Changes in cyclic AMP receptor properties during adaptation in Dictyostelium discoideum

1990 ◽  
Vol 95 (4) ◽  
pp. 623-629
Author(s):  
M.E. Luderus ◽  
M.J. Spijkers ◽  
R. Van Driel
Keyword(s):  
Cyclic Amp ◽  
G Protein ◽  
Dictyostelium Discoideum ◽  
Receptor Binding ◽  
Molecular Basis ◽  
Guanine Nucleotides ◽  
Cyclic Process ◽  
Binding Properties ◽  
Receptor System ◽  
Receptor Affinity

In developing Dictyostelium discoideum cells, binding of cyclic AMP to the chemotactic receptor has been shown to oscillate. These oscillations represent cycles of activation, adaptation and deadaptation of the cyclic AMP receptor system. We studied the molecular basis of these oscillatory changes in cyclic AMP receptor binding. We developed a rapid method of lysing cells during the course of the oscillations. This method guaranteed good preservation of ligand binding properties of the cyclic AMP receptor. We found that oscillations in cyclic AMP binding resulted from changes in receptor affinity. The total number of receptors did not significantly change during oscillations. Our experiments also showed that both GTP and GDP abolished oscillations in receptor binding completely, presumably by acting via a G protein. The guanine nucleotides reduced the affinity of the receptor at all time-points of the oscillation cycle to the minimal, i.e. adapted, level. We conclude that the cyclic process of activation, adaptation and de-adaptation in D. discoideum, at cyclic AMP receptor level, involves changes in receptor-G protein interaction. During adaptation, the affinity of the cyclic AMP receptor decreases and the receptor becomes insensitive to guanine nucleotides.

scholarly journals A pharmacologically distinct cyclic AMP receptor is responsible for the regulation of gp80 expression in Dictyostelium discoideum.

1990 ◽  
Vol 10 (7) ◽  
pp. 3297-3306 ◽  
Author(s):  
P C Ma ◽  
C H Siu
Keyword(s):  
Cyclic Amp ◽  
Adenylate Cyclase ◽  
Dictyostelium Discoideum ◽  
Surface Glycoprotein ◽  
Intracellular Camp ◽  
Cell Surface Glycoprotein ◽  
Cyclase Activation ◽  
Adenylate Cyclase Activation ◽  
Camp Receptor

The EDTA-resistant cell-cell adhesion expressed at the aggregation stage of Dictyostelium discoideum is mediated by a cell surface glycoprotein of Mr 80,000 (gp80). The expression of gp80 is developmentally regulated by cyclic AMP (cAMP). In vitro nuclear run-on experiments show that transcription of the gp80 gene is initiated soon after the onset of development. The basal level of gp80 transcription is significantly augmented by exogenous cAMP pulses. Interestingly, in analog studies, 2'-deoxy-cAMP, 8-bromo-cAMP, and N6-monobutyryl-cAMP are all capable of inducing a rapid accumulation of gp80 mRNA, suggesting the presence of a unique cAMP receptor that responds equally well to these analogs. To determine whether intracellular cAMP plays a role in the regulation of gp80 expression, caffeine was used to block cAMP-induced receptor-mediated adenylate cyclase activation. Expression of gp80 mRNA was blocked in caffeine-treated cells but could be substantially restored by treatment with exogenous cAMP pulses, suggesting that adenylate cyclase activation is not required. gp80 expression was also examined in the signal transduction mutants synag 7 and frigid A. In both mutants, gp80 was expressed at the basal level. Pulses of cAMP as well as 2'-deoxy-cAMP and N6-monobutyryl-cAMP were capable of restoring the normal level of gp80 expression in synag 7 cells. These results, taken together, indicate bimodal regulation of gp80 expression during development and the involvement of a novel cAMP receptor in the transmembrane signalling pathway that regulates gp80 gene expression.

Calcium uptake and gp80 messenger RNA destabilization follows cAMP receptor down regulation in Dictyostelium discoideum

1994 ◽  
Vol 6 (8) ◽  
pp. 883-895 ◽  
Author(s):  
Gláucia Mendes Souza ◽  
Claudette Klein ◽  
JoséCarlos Da Costa Maia ◽  
Aline Maria Da Silva
Keyword(s):  
Dictyostelium Discoideum ◽  
Messenger Rna ◽  
Calcium Uptake ◽  
Down Regulation ◽  
Camp Receptor

Cyclic AMP regulation of early gene expression in Dictyostelium discoideum: mediation via the cell surface cyclic AMP receptor

1987 ◽  
Vol 7 (1) ◽  
pp. 458-469
Author(s):  
S K Mann ◽  
R A Firtel
Keyword(s):  
Cyclic Amp ◽  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Early Gene ◽  
Developmental Cycle ◽  
Intracellular Camp ◽  
Flanking Sequence ◽  
Coding Region ◽  
Camp Receptor

We examined two sets of genes expressed early in the developmental cycle of Dictyostelium discoideum that appear to be regulated by cyclic AMP (cAMP). The transcripts of both sets of genes were not detectable in vegetative cells. During normal development on filter pads, RNA complementary to these genes could be detected at about 2 h, peaked around 6 to 8 h, and decreased gradually thereafter. Expression of these genes upon starvation in shaking culture was stimulated by pulsing the cells with nanomolar levels of cAMP, a condition that mimics the in vivo pulsing during normal aggregation. Expression was inhibited by caffeine or by continuous levels of cAMP, a condition found later in development when in vivo expression of these genes decreased. The inhibition of caffeine could be overcome by pulsing cells with cAMP. These results suggest that the expression is mediated via the cell surface cAMP receptor, but does not require a rise in intracellular cAMP. mRNA from a gene of the second class was induced upon starvation, peaked by 2.5 h of development, and then declined. In contrast to the other genes, its expression was maintained by continuous levels of cAMP and repressed by cAMP pulses. These and other results on a number of classes of developmentally regulated genes indicates that changing levels of cAMP, acting via the cell surface cAMP receptor, are involved in controlling these groups of genes. We also examined the structure and partial sequence of the cAMP pulse-induced genes. The two tandemly duplicated M3 genes were almost continuously homologous over the sequenced portion of the protein-coding region except for a region near the N-terminal end. The two M3 genes had regions of homology in the 5' flanking sequence and showed slight homology to the same regions in gene D2, another cAMP pulse-induced gene. D2 showed extremely significant homology over its entire sequenced length to an acetylcholinesterase. The results presented here and by others suggest that expression of many early genes in D. discoideum is regulated via the cell surface cAMP receptor. We expect that many of these genes may play essential roles in early Dictyostelium development and could code for elements of the cAMP signal transduction pathway involved in aggregation.

Forms of the chemotactic adenosine cyclic 3',5'-phosphate receptor in isolated Dictyostelium discoideum membranes and interconversions induced by guanine nucleotides

Biochemistry ◽  
1986 ◽  
Vol 25 (6) ◽  
pp. 1314-1320 ◽  
Author(s):  
Pim M. W. Janssens ◽  
Jos C. Arents ◽  
Peter J. M. Van Haastert ◽  
Roel Van Driel
Keyword(s):  
Dictyostelium Discoideum ◽  
Guanine Nucleotides

scholarly journals Cyclic AMP regulation of early gene expression in Dictyostelium discoideum: mediation via the cell surface cyclic AMP receptor.

1987 ◽  
Vol 7 (1) ◽  
pp. 458-469 ◽  
Author(s):  
S K Mann ◽  
R A Firtel
Keyword(s):  
Cyclic Amp ◽  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Early Gene ◽  
Developmental Cycle ◽  
Intracellular Camp ◽  
Flanking Sequence ◽  
Coding Region ◽  
Camp Receptor

We examined two sets of genes expressed early in the developmental cycle of Dictyostelium discoideum that appear to be regulated by cyclic AMP (cAMP). The transcripts of both sets of genes were not detectable in vegetative cells. During normal development on filter pads, RNA complementary to these genes could be detected at about 2 h, peaked around 6 to 8 h, and decreased gradually thereafter. Expression of these genes upon starvation in shaking culture was stimulated by pulsing the cells with nanomolar levels of cAMP, a condition that mimics the in vivo pulsing during normal aggregation. Expression was inhibited by caffeine or by continuous levels of cAMP, a condition found later in development when in vivo expression of these genes decreased. The inhibition of caffeine could be overcome by pulsing cells with cAMP. These results suggest that the expression is mediated via the cell surface cAMP receptor, but does not require a rise in intracellular cAMP. mRNA from a gene of the second class was induced upon starvation, peaked by 2.5 h of development, and then declined. In contrast to the other genes, its expression was maintained by continuous levels of cAMP and repressed by cAMP pulses. These and other results on a number of classes of developmentally regulated genes indicates that changing levels of cAMP, acting via the cell surface cAMP receptor, are involved in controlling these groups of genes. We also examined the structure and partial sequence of the cAMP pulse-induced genes. The two tandemly duplicated M3 genes were almost continuously homologous over the sequenced portion of the protein-coding region except for a region near the N-terminal end. The two M3 genes had regions of homology in the 5' flanking sequence and showed slight homology to the same regions in gene D2, another cAMP pulse-induced gene. D2 showed extremely significant homology over its entire sequenced length to an acetylcholinesterase. The results presented here and by others suggest that expression of many early genes in D. discoideum is regulated via the cell surface cAMP receptor. We expect that many of these genes may play essential roles in early Dictyostelium development and could code for elements of the cAMP signal transduction pathway involved in aggregation.

Sign in / Sign up

Export Citation Format

Share Document