Biomaterial Database

Agonist-stimulated high-affinity GTPase in Dictyostelium membranes. 1988

B E Snaar-Jagalska, and K H Jakobs, and P J Van Haastert

Cell Biology and Genetics Unit, Zoological Laboratory, Leiden, The Netherlands.

GTP hydrolysis in Dictyostelium discoideum membranes is caused by a low (Km greater than 1 mM) and a high affinity (Km 6.5 microM) GTPase. cAMP enhances GTP hydrolysis apparently by increasing the affinity of the high affinity GTPase (stimulated Km 4.5 microM); the low affinity GTPase was not affected by cAMP. Stimulation of GTP hydrolysis by cAMP was maximal at early time points and declined thereafter. A half-maximal stimulation of GTPase occurred at 3 microM cAMP and the specificity of cAMP derivatives for stimulation of GTPase activity showed a close correlation with the specificity for binding to the cell surface cAMP receptor. Treatment of D. discoideum cells with pertussis toxin decreased the cAMP-induced stimulation of GTPase from 42 +/- 6% in control cells to 17 +/- 9% in pertussis toxin-treated cells. These results suggest that the interaction of cAMP with its surface receptor leads to stimulation of high affinity GTPase in D. discoideum membranes. At least one of those enzymes may represent a guanine nucleotide-binding protein sensitive to pertussis toxin.

UI	MeSH Term	Description	Entries
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D010566	Virulence Factors, Bordetella	A set of BACTERIAL ADHESINS and TOXINS, BIOLOGICAL produced by BORDETELLA organisms that determine the pathogenesis of BORDETELLA INFECTIONS, such as WHOOPING COUGH. They include filamentous hemagglutinin; FIMBRIAE PROTEINS; pertactin; PERTUSSIS TOXIN; ADENYLATE CYCLASE TOXIN; dermonecrotic toxin; tracheal cytotoxin; Bordetella LIPOPOLYSACCHARIDES; and tracheal colonization factor.	Bordetella Virulence Factors,Agglutinogen 2, Bordetella Pertussis,Bordetella Virulence Determinant,LFP-Hemagglutinin,LP-HA,Leukocytosis-Promoting Factor Hemagglutinin,Lymphocytosis-Promoting Factor-Hemagglutinin,Pertussis Agglutinins,Agglutinins, Pertussis,Determinant, Bordetella Virulence,Factor Hemagglutinin, Leukocytosis-Promoting,Factor-Hemagglutinin, Lymphocytosis-Promoting,Factors, Bordetella Virulence,Hemagglutinin, Leukocytosis-Promoting Factor,LFP Hemagglutinin,LP HA,Leukocytosis Promoting Factor Hemagglutinin,Lymphocytosis Promoting Factor Hemagglutinin,Virulence Determinant, Bordetella
D010744	Phosphoric Monoester Hydrolases	A group of hydrolases which catalyze the hydrolysis of monophosphoric esters with the production of one mole of orthophosphate.	Phosphatase,Phosphatases,Phosphohydrolase,Phosphohydrolases,Phosphomonoesterase,Phosphomonoesterases,Phosphoric Monoester Hydrolase,Hydrolase, Phosphoric Monoester,Hydrolases, Phosphoric Monoester,Monoester Hydrolase, Phosphoric
D011953	Receptors, Cyclic AMP	Cell surface proteins that bind cyclic AMP with high affinity and trigger intracellular changes which influence the behavior of cells. The best characterized cyclic AMP receptors are those of the slime mold Dictyostelium discoideum. The transcription regulator CYCLIC AMP RECEPTOR PROTEIN of prokaryotes is not included nor are the eukaryotic cytoplasmic cyclic AMP receptor proteins which are the regulatory subunits of CYCLIC AMP-DEPENDENT PROTEIN KINASES.	Cyclic AMP Receptors,cAMP Receptors,Cyclic AMP Receptor,Receptors, cAMP,cAMP Receptor,Receptor, Cyclic AMP,Receptor, cAMP
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D004023	Dictyostelium	A genus of protozoa, formerly also considered a fungus. Its natural habitat is decaying forest leaves, where it feeds on bacteria. D. discoideum is the best-known species and is widely used in biomedical research.	Dictyostelium discoideum,Dictyostelium discoideums,Dictyosteliums,discoideum, Dictyostelium
D006160	Guanosine Triphosphate	Guanosine 5'-(tetrahydrogen triphosphate). A guanine nucleotide containing three phosphate groups esterified to the sugar moiety.	GTP,Triphosphate, Guanosine
D006868	Hydrolysis	The process of cleaving a chemical compound by the addition of a molecule of water.
D000242	Cyclic AMP	An adenine nucleotide containing one phosphate group which is esterified to both the 3'- and 5'-positions of the sugar moiety. It is a second messenger and a key intracellular regulator, functioning as a mediator of activity for a number of hormones, including epinephrine, glucagon, and ACTH.	Adenosine Cyclic 3',5'-Monophosphate,Adenosine Cyclic 3,5 Monophosphate,Adenosine Cyclic Monophosphate,Adenosine Cyclic-3',5'-Monophosphate,Cyclic AMP, (R)-Isomer,Cyclic AMP, Disodium Salt,Cyclic AMP, Monoammonium Salt,Cyclic AMP, Monopotassium Salt,Cyclic AMP, Monosodium Salt,Cyclic AMP, Sodium Salt,3',5'-Monophosphate, Adenosine Cyclic,AMP, Cyclic,Adenosine Cyclic 3',5' Monophosphate,Cyclic 3',5'-Monophosphate, Adenosine,Cyclic Monophosphate, Adenosine,Cyclic-3',5'-Monophosphate, Adenosine,Monophosphate, Adenosine Cyclic
D020558	GTP Phosphohydrolases	Enzymes that hydrolyze GTP to GDP. EC 3.6.1.-.	GTPase,GTPases,Guanosine Triphosphate Phosphohydrolases,Guanosinetriphosphatases,GTP Phosphohydrolase,Phosphohydrolase, GTP,Phosphohydrolases, GTP,Phosphohydrolases, Guanosine Triphosphate,Triphosphate Phosphohydrolases, Guanosine